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Edited by Roland Ulber, Dieter Sell, and Thomas Hirth Renewable Raw Materials
Related Titles Soetaert, W., Vandamme, E. J. (eds.)
Industrial Biotechnology Sustainable Growth and Economic Success 2010 Hardcover ISBN: 978-3-527-31442-3
Soetaert, W., Vandamme, E. (eds.)
Biofuels Hardcover ISBN: 978-0-470-02674-8
Deublein, D., Steinhauser, A.
Biogas from Waste and Renewable Resources An Introduction 2008 Hardcover ISBN: 978-3-527-31841-4
Wengenmayr, R., Bührke, T. (eds.)
Renewable Energy Sustainable Energy Concepts for the Future 2008 Hardcover ISBN: 978-3-527-40804-7
Edited by Roland Ulber, Dieter Sell, and Thomas Hirth
Renewable Raw Materials New Feedstocks for the Chemical Industry
The Editors Prof. Dr. Roland Ulber TU Kaiserslautern, Maschinenb. AG Bioverfahrenstechnik,Geb 44 Gottlieb-Daimler-Str. 67663 Kaiserslautern Germany Dr. Dieter Sell DECHEMA e.V. Bioverfahrenstechnik Theodor-Heuss-Allee 25 60486 Frankfurt Germany Prof. Dr. Thomas Hirth Fraunhofer Institut für Grenzflächen u. Bioverf. IGB Nobelstr. 12 70569 Stuttgart Germany
All books published by Wiley-VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate. Library of Congress Card No.: applied for British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at . © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law. Cover Design Grafik-Design Schulz, Fußgönheim Typsetting Toppan Best-set Premedia Limited Printing and Binding Strauss GmbH, Mörlenbach Printed in the Federal Republic of Germany Printed on acid-free paper ISBN: 978-3-527-32548-1 ePDF ISBN: 978-3-527-63421-7 oBook ISBN: 978-3-527-63419-4 EPub ISBN: 978-3-527-63420-0 Mobi ISBN: 978-3-527-63422-4
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Contents List of Contributors XI
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Introduction to Renewable Resources in the Chemical Industry 1 Roland Ulber, Kai Muffler, Nils Tippkötter, Thomas Hirth, and Dieter Sell
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Plants as Bioreactors: Production and Use of Plant-Derived Secondary Metabolites, Enzymes, and Pharmaceutical Proteins 7 Peter C. Morris, Peter Welters, and Bernward Garthoff Introduction 7 Renewable Resources in the Chemical Industry 7 Commodity Production 8 Production Problems 9 Natural Rubber as Compared to Synthetic Rubber 12 Cellulose and Other Fibers 12 Paper Production 13 Starch Production 15 Sugar Production and Improvement of Yield by Genetic Engineering 16 Fine Chemicals and Drugs 17 Plant Cell Culture 17 Terpenoids 17 Amino Acids 18 Fatty Acid Derivatives 18 Plant Protection 19 Small Molecule Drugs 19 Polyphenols and Resveratrol 22 Plant-Made Pharmaceuticals 22 Vaccines 24 Monoclonal Antibodies 25 Other Therapeutic Proteins 26 Methodologies for PMP Production 26 References 28
2.1 2.2 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7 2.3 2.3.1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.6 2.3.7 2.4 2.4.1 2.4.2 2.4.3 2.4.4
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Contents
3 3.1 3.2 3.2.1 3.2.2 3.2.3 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.4 3.5
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4.1 4.2 4.2.1 4.2.2 4.2.2.1 4.2.2.2 4.2.2.3 4.2.2.4 4.2.2.5 4.2.2.6 4.2.3 4.3 4.3.1 4.3.1.1 4.3.1.2 4.3.2 4.3.3 4.4 4.4.1 4.4.2 4.4.3
World Agricultural Capacity 33 John K. Hughes Petrochemicals Today 33 Renewable Chemicals 34 Traditional Uses 34 Potential Raw Materials 34 Scope for Substitution 35 Agricultural Production 36 Current Situation 36 Increasing Production 40 Increasing Availability 43 Future Prospects 43 Supplying the Chemical Industry 44 Summary 45 References 46 Logistics of Renewable Raw Materials 49 Magnus Fröhling, Jörg Schweinle, Jörn-Christian Meyer, and Frank Schultmann Introduction 49 Determining Factors for the Logistics of Industrial Utilization Chains for Renewable Raw Materials 50 Operating in a Natural Environment 50 Characterization of Selected Renewable Raw Materials 52 Oil Crops 52 Sugar Crops 57 Starch Crops 60 Lignocellulosic Biomass 64 Other Biogenic Residues 67 Algae 68 Actors and Stakeholders – Mobilization of the Renewable Raw Materials 69 Processing Steps of Renewable Raw Material Logistic Chains 71 Cultivation and Harvesting for Selected Types of Renewable Raw Materials 71 Agricultural Production 71 Forest Production 75 Transport 79 Storage 81 Design and Planning of Renewable Raw Material Logistic Chains 82 Determining Plant Sizes: Economies of Scale vs. Minimization of Transport Load 82 Facility Location Planning and Determining the Logistical Structure of a Renewable Raw Material Utilization Chain 85 Consideration of Competing Utilization Pathways 86
Contents
4.4.4 4.5
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5.1 5.2 5.3 5.3.1 5.3.2 5.3.3 5.4 5.5 5.5.1 5.5.2 5.5.2.1 5.5.2.2 5.5.2.3 5.5.2.4 5.5.2.5 5.5.3 5.6 5.6.1 5.6.2 5.6.3 5.7
6 6.1 6.2 6.2.1 6.2.2 6.2.3 6.2.4 6.3 6.3.1
Demand for Integrated Assessment and Planning Methods for Renewable Raw Material Logistic Chains 88 Summary and Conclusions 89 References 90 Existing Value Chains 95 Christoph Syldatk, Georg Schaub, Ines Schulze, Dorothea Ernst, and Anke Neumann Industrial Biotechnology Today – Main Products, Substrates, and Raw Materials 95 White Biotechnology – Future Products from Today’s Raw Materials? 97 Effects of Feedstock and Process Technology on the Production Cost of Chemicals 100 Introduction 100 Simplified Procedure for Cost Estimation 102 Example: Alkenes from Petroleum Fractions and from Bioethanol 104 New Raw Materials for White Biotechnology 105 Case Studies: Lignocellulose as Raw Material and Intermediates 107 Bioethanol and Chemical Production from Lignocellulosic Biomass 107 Limitations 110 Substrate 110 Pretreatment 110 Composition of Biomass 111 Hydrolysis 111 Fermentation 112 Research and Development Potential 112 Case Studies: “SCOs” as Raw Material and Intermediate 114 Microbial SCOs 114 Industrial Use of Microbial SCOs 114 Limitations and Research and Development Potential 115 Conclusions 117 References 118 Future Biorefineries 121 Abbas Kazmi and James Clark Introduction 121 Current and Future Outlook for Biofuels 122 Bioethanol 123 Biobutanol 125 Biodiesel 125 Microalgae 127 Chemicals from Renewable Resources 129 Succinic Acid 129
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6.3.2 6.3.3 6.3.4 6.3.5 6.4 6.4.1 6.4.2 6.4.3 6.4.4 6.5 6.6
Aspartic Acid 131 Levulinic Acid 132 Sorbitol Acid (SBA) 132 Glycerol 133 The Role of Clean Technologies in Biorefineries Separation Technologies 134 Supercritical CO2 Extraction 135 Cellulose Hydrolysis 136 Thermochemical Processing 138 The Size of Future Biorefineries 139 Conclusions 139 References 140
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Economic and Social Implications of the Industrial Use of Renewable Raw Materials 143 Antonio Lopolito, Maurizio Prosperi, Roberta Sisto, and Pasquale Pazienza Introduction 143 Biorefinery Industry and the Development of EU Rural Areas 146 Overview of Different Models of Biorefinery Industry 146 Potential Effects of the Global Model 147 Potential Effects of the Local Model 149 Which Biorefinery Model for EU Rural Areas? 149 From Analytic to Systemic Modeling Methodology of the Biorefinery Industry 150 The Search for a Theoretical Framework Capable of Dealing with Novelty, Uncertainty, Ignorance, and Unpredictability 150 FCMs to Find Knowledge in Complex Systems 152 Stakeholders’ Perceptions of Biorefinery in Rural Areas: Issues and Lessons from the South of Italy 155 A Network Analysis of Stakeholders’ Knowledge 156 Interpretation of Results 162 Determinants 162 Influential Conditions 164 Effects 164 Concluding Remarks 165 Acknowledgments 166 References 166
7.1 7.2 7.2.1 7.2.2 7.2.3 7.2.4 7.3 7.3.1 7.3.2 7.4 7.4.1 7.4.2 7.4.2.1 7.4.2.2 7.4.2.3 7.5
8 8.1 8.2 8.3 8.4 8.5 8.5.1
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Biobased Products – Market Needs and Opportunities 169 Rainer Busch Introduction 169 Definition 170 Basic Technology for the Conversion of Renewable Raw Materials 171 Classes of Bioproducts 172 Current Status 173 Polymers 174
Contents
8.5.1.1 8.5.1.2 8.5.1.3 8.5.1.4 8.5.2 8.5.3 8.5.4 8.6
Polylactic Acid 174 Polyethylene 175 Others 175 Potential 176 Lubricants 177 Solvents 179 Surfactants 180 Outlook and Perspectives 182 References 185
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Life-Cycle Analysis of Biobased Products Liselotte Schebek
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9.1 9.2 9.2.1 9.2.2 9.2.2.1 9.2.2.2 9.2.2.3 9.2.2.4 9.2.2.5 9.2.3 9.3 9.3.1 9.3.2 9.3.2.1 9.3.2.2 9.3.2.3 9.4
Introduction: Why Life-Cycle Analysis of Biobased Products? 187 The Methodological Framework of LCA 188 General Goal and Framework of LCA 188 Phases of LCA 189 General Scheme 189 Goal and Scope Definition 190 Life Cycle Inventory (LCI) 190 Life Cycle Impact Assessment (LCIA) 192 Interpretation 196 Databases and Software for LCA 196 Specific Methodological Aspects for LCA for Biobased Products 196 Methodological Outline 196 Accounting for Land Use in LCA 198 Conceptual Aspects for Treatment of Land Use in LCA 198 Land Occupation and Land Transformation 198 Impacts of Land Use 199 LCA Studies for Biobased Products: Major Findings and Insights 200 9.4.1 Biofuels 200 9.4.2 Biopolymers 204 9.4.3 Products from Biotechnological Processes 206 9.4.4 Composites 208 9.4.5 Consumer Products 209 9.4.5.1 Packaging 210 9.4.5.2 Products for the Building Sector 210 9.4.5.3 Lubricants 210 9.5 Conclusions 211 References 212 10
Conclusion 217 Roland Ulber, Thomas Hirth, and Dieter Sell
Index 221
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List of Contributors Rainer Busch T+I Consulting Bismarckstraße 15 76530 Baden-Baden Germany James Clark University of York Green Chemistry Centre of Excellence YO10 5DD, York United Kingdom Dorothea Ernst Karlsruhe Institute of Technology Faculty of Chemical and Process Engineering 76128 Karlsruhe Germany Magnus Fröhling Karlsruhe Institute of Technology (KIT) Institute for Industrial Production Hertzstraße 16 76187 Karlsruhe Germany Bernward Garthoff Cluster BIO.NRW Merowingerplatz 1 40225 Düsseldorf Germany
Thomas Hirth IGVT der Universität Stuttgart und Fraunhofer-Institut für Grenzflächen und Bioverfahrenstechnik Institut für Grenzflächenverfahrenstechnik Nobelstrasse 12 70569 Stuttgart Germany John K. Hughes The Food and Environment Research Agency Sand Hutton YO41 1LZ, York United Kingdom Abbas Kazmi University of York Green Chemistry Centre of Excellence YO10 5DD, York United Kingdom Antonio Lopolito University of Foggia Department of Production and Innovation in Mediterranean Agriculture and Food Systems (PrIME) 71100 Foggia Italy
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List of Contributors
Jörn-Christian Meyer Karlsruhe Institute of Technology (KIT) Institute for Industrial Production Hertzstraße 16 76187 Karlsruhe Germany Peter C. Morris School of Life Sciences Heriot-Watt University Riccarton, Edinburgh EH14 4AS UK Kai Muffler TU Kaiserslautern Lehrgebiet Bioverfahrenstechnik Gottlieb-Daimler-Str. 44 67663 Kaiserslautern Germany Anke Neumann Karlsruhe Institute of Technology Faculty of Chemical and Process Engineering 76128 Karlsruhe Germany Pasquale Pazienza University of Foggia Department of Economics Mathematics and Statistics (SEMS) 71100 Foggia Italy Maurizio Prosperi University of Foggia Department of Production and Innovation in Mediterranean Agriculture and Food Systems (PrIME) 71100 Foggia Italy
Georg Schaub Karlsruhe Institute of Technology Faculty of Chemical and Process Engineering 76128 Karlsruhe Germany Liselotte Schebek Technische Universität Darmstadt Fachbereich Bauingenieurwesen und Geodäsie (FB 13) Fachgebiet Industrielle Stoffkreisläufe Insitut WAR Petersenstr. 13 64287 Darmstadt Germany Forschungszentrum Karlsruhe GmbH Institut für Technikfolgenabschätzung und Systemanalyse Zentralabteilung Technikbedingte Stoffströme (ITAS-ZTS) 76021 Karlsruhe Germany Frank Schultmann Karlsruhe Institute of Technology (KIT) Institute for Industrial Production Hertzstraße 16 76187 Karlsruhe Germany Ines Schulze Karlsruhe Institute of Technology Faculty of Chemical and Process Engineering 76128 Karlsruhe Germany
List of Contributors
Jörg Schweinle Johann Heinrich von Thünen-Institute (vTI) Institute of Forest Based Sector Economics Federal Research Institute for Rural Areas Forestry and Fisheries 21002 Hamburg Germany Dieter Sell DECHEMA e.V. Abteilung Biotechnologie Theodor-Heuss-Allee 25 60486 Frankfurt/Main Germany Roberta Sisto University of Foggia Department of Economics, Mathematics and Statistics (SEMS) 71100 Foggia Italy
Christoph Syldatk Karlsruhe Institute of Technology Faculty of Chemical and Process Engineering 76128 Karlsruhe Germany Nils Tippkötter TU Kaiserslautern Lehrgebiet Bioverfahrenstechnik Gottlieb-Daimler-Str. 44 67663 Kaiserslautern Germany Roland Ulber TU Kaiserslautern Lehrgebiet Bioverfahrenstechnik Gottlieb-Daimler-Str. 44 67663 Kaiserslautern Germany Peter Welters Phytowelt Green Technologies Kölsumer Weg 33 41334 Nettetal Germany
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1 Introduction to Renewable Resources in the Chemical Industry Roland Ulber, Kai Muffler, Nils Tippkötter, Thomas Hirth, and Dieter Sell
Processes in the chemical industry are historically based on fossil resources. During industrial revolution, energy sources like peat and such renewable biomasses as wood were substituted by coal and later on by natural gas and petroleum oil. The latter has been, until now, the main resource for raw materials and the energy supply for the private sector. Due to its very beneficial properties in terms of chemical synthesis processes, only a minor proportion of approximately 10% of this plentiful resource is used for such purposes, whereas 90% is utilized for energy and transport. With regard to the increasing population and energy demand and oil consumption of developing countries, the limited availability of crude oil, and financially motivated trading operations, the price of oil rises steadily and reached a peak of nearly 150 USD per barrel in 2008. It is assumed that most of the known so-called supergiant oil-fields cross the oil-peak, which comes along with a decrease in the discovery of novel oil springs. Therefore, alternatives have to be introduced to reduce the dependency on these transient fossil fuels. But one has to keep in mind that alternative fuels and resources for chemical building blocks have to compete against classical fossil compounds. Currently, the prices of most bulk and specialty chemicals are too low for biotechnological routes to compete. It is estimated that competition begins at feedstock prices above $2 per kilogram. Nevertheless, the share of biotechnologically produced chemicals is expected to increase from approximately 5% to 20% in the year 2010. The greatest impact is expected in the segment of fine and specialty chemicals with up to 60% of the products based on biotechnological processes. Interfacing with green biotechnology for enhanced crop properties and increased plant breeding can be expected. More attention is paid to the lignocellulose feedstock, which is extensively discussed and examined to be used as a sustainable raw material for ethanol production. In addition, a few current trends focus on C1 carbonic compounds such as methanol and methane, fatty acids and glycerol from plant oil, and whey-based substrates that can be used as input compounds for a chemical refinery. If one has a closer look to current activities of oil companies, it is obvious that the time is changing. Several efforts to utilize sustainable biomass feedstocks for recovering fuel substitutes were carried out by these companies. But the Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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exploitation and utilization of the biomass feedstock have to be implemented very carefully to avoid such an already occurred competition of energy crops with food production, if first-generation biomass fuels were considered. However, the complete substitution of fossil resources by biobased fuels and raw materials within the near future is quite improbable, considering the current process operation’s dependency on large amount of biomass feedstock. Therefore, socioeconomic trends must focus on a holistic approach, where fossil as well as biological resources have to be used in a complementary way. At least at the laboratory scale, for 6 of the 10 best sellers of the chemical industry alternative biotechnological production processes are under development (ethylene, ethylene oxide, dichloroethane, propylene, formaldehyde, and propylene oxide). In Western Europe alone, the annual demand for ethylene and propylene is 40.5 million tonnes. World production of the basic building blocks of the chemical industry, including polymers, exceeds 500 million tonnes. This fact clearly shows that large quantities of renewable raw materials must be made available for the production of bulk chemicals. Despite the 5.6 million hectares of arable land currently lying fallow in the EU, this cannot be limited to the provision of sugar or starch. On the contrary, what is required is the holistic utilization of diverse renewable resources. Nature provides around 170 billion tonnes of plant biomass, of which hitherto only approximately 3–4% have been commercially exploited. The crux of the matter is how much can, and indeed may, be used of the remaining 96% in a sustainable way? And how much energy will this entail? If one considers the biomass feedstock, the number of different categories is enormous and includes grains, sugar crops, oilseed crops, agricultural wastes, food-processing wastes (liquid and solid), wood, wood chips, bark, mill residues, forest residues, pulping liquors, manures, and algae. With regard to an increasing utilization of crops in the material and energy sector, the prices for comestible goods also increase and a couple of social problems arise. Therefore, the exploitation of forest residues or special planted wood-based biomass is – based on our current knowledge – accompanied only by insignificant social problems. Especially for European countries, prosperous predictions for utilization of such materials do exist. Owing to a declining population, the need for agricultural crop lands for food supply will decrease and could be used for industrial plantations. As a positive consequence, new collaborations between producers (farmers) and chemical manufacturers will be established in analogy to the already existing collaborations between the starch-processing companies and manufacturers. One potential starting point is the development of the lignocellulose biorefinery. However, the sustainable development of the biorefinery depends on the extensive process integration. A concept devised solely for the production of basic and fine chemicals may well fail to achieve its target. More importantly, the materials applied should be used both for energy (in the form of heat and power) and for the production of chemicals and materials. All planning must allow for the fact that the renewable resources in question should not only be allocated to biotechnology but also in fact in the area of energy supply where there is a tendency to draw increasingly on biomass. Hütermann and Metzger, for example, state that
1 Introduction to Renewable Resources in the Chemical Industry
“… global energy provision on the basis of biomass is feasible without detriment to food production. …” According to their calculations, a biobased economy would require 22.3 billion tonnes of bio-oil from pyrolysis. This corresponds to approximately 35 billion tonnes of biomass solely for conversion into energy. In the construction materials sector, too, there is a growing trend to utilize renewable resources. To quote the “Informationsknoten nachwachsende Rohstoffe” (Renewable Resources Information Centre), “… nature provides a huge range of plant and animal raw materials that are suitable for a variety of applications. The challenge for the future is to exploit this inexhaustible raw materials potential without detriment either to man or to the environment and without impairing the standard of living of the population. …”. Only the concerted efforts of all interest groups in the field of renewable resources can pave the way for a meaningful development. In the following chapters, the options for the biotechnological and chemical industries will be examined in more detail. In view of the raw materials figures initially mentioned, one of the priorities will be (ligno)cellulose as, with around 95%, it accounts for the bulk of renewable raw materials. A further priority will be the more intensive utilization of methane and methanol from both fossil and renewable sources. Assuming an estimated annual biomass production of 170 billion tonnes by biosynthesis, of which 75% are carbohydrates mainly in the form of cellulose, chitin, starch, and sucrose, 20% lignin, and only 5% other natural products such as fats (oils), proteins, and diverse ingredients, the prime concern should be efficient access to carbohydrates and processing them into chemical mass products and finished products. This will not take place overnight since the relevant technologies first have to be developed; moreover a shift from fossil to sustainable processes can only be implemented if it is seen to be economically viable. The substitution of fossil resources by renewable resources can, therefore, only proceed in stages. To combine the markets for fossil and renewable resources would only make a prognosis of the most favorable time for the change more difficult. Raw materials on the basis of biomass cannot simply be converted into conventional plants like naphtha crackers; hence it is postulated that new processes for the conversion of biomass first need to be developed. If used intelligently, chemical reaction technology, including catalysis and process engineering together with biotechnology, may provide economic solutions to this technological problem. The following strategies are, in principle, possible:
• • • •
utilization of the chemical structures produced by nature without any chemical modification; one-step modification of these structures; multistep chemical modification; total degradation to C-1 fragments (e.g., synthesis gas or methane) and controlled synthesis to obtain the desired molecules.
The chemical industry owes its success to the principle of unit construction: from simple basic substances, like ethylene, carbon monoxide, or hydrogen, more complex precursors can be produced under controlled conditions by chemical
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reactions; due to the variety of combination options, the latter can in turn be converted into inconceivable quantities of derivatives and end products. Chemistry learned how to produce chemically pure basic substances from oil that are simple to handle and exactly defined; this is performed highly efficiently in refineries. This was the key to its success. Without exact knowledge of this functional principle, the triumphant success of plastics would have been just as impossible as the production of thousands of other chemical products that today make our lives safe and comfortable. Within the following chapters, this book tries to answer some of the important questions to establish biorefineries within the existing chemical industry. What should be the impact from plant breeding for new biorefineries? Is it possible to design new and better plants which fulfill most of the requirements (high contents of fermentable raw materials, less by-products, easy to hydrolyze)? Initially the chemical industry considered fermentation of plant carbohydrates as the only viable solution. But now, with the increasing success of globally grown genetically modified plants, plant enzymes, cell cultures, and whole plants have been taken seriously for chemical production processes. Pharmaceutical proteins, SMDs, and fine chemicals have been the first choice for production. But with ever-rising prices of fossil resources, chemical commodities such as platform chemicals (e.g., succinate, itaconic acid), intermediates, or polymers are now considered as economically viable (see Chapter 2). However, is the world agro capacity big enough to deliver all raw materials needed? The primary purpose of agriculture is food production and has been so throughout human history. During the last decade, environmental and economic concerns have led to growing interest in fuel and energy crop production. Therefore, the production of renewable chemicals from agricultural raw materials will be in direct competition with both food and fuel production for space, resources, labor, and funds. Although the high value of chemical products may make them economically viable, they may have an undesirable competitive effect on food production. However, food, fuel, and chemical production are not necessarily mutually exclusive. The biorefinery concept aims to make best use of whole crop plants by producing numerous products from a single resource (discussed in Chapter 3). In comparison to their fossil counterparts, process chains based on renewable raw materials differ in many aspects. Operations for cultivation, harvesting, and provision of renewable raw materials take place in a natural environment. The raw materials accrue spatially distributed on large areas. Amount and characteristics of the resources underlie seasonal variances and restrictions. As a rule, the abilities and capabilities for storage are limited. Long-distance transports are disadvantageous because of comparable high water content and low calorific values. Thus, Chapter 4 explains the essential adjustments for the logistics of renewable raw materials. Looking at the existing value chain of industrial biotechnology, all fermentation processes which have been commercialized in the last decades for the production of one of the building blocks such as ethanol or amino acids presently rely on carbohydrates as feedstock. Moreover, the majority of fermentation processes, which recently are in the feasibility stage, also start from these feedstocks at the moment. Chapter 5 gives an
1 Introduction to Renewable Resources in the Chemical Industry
overview about the existing value chains and the products already produced in the so-called type-one biorefineries, whereas future biorefineries are described in Chapter 6. The establishment of new industrial firms, such as a biorefinery, in a rural area can be seen as an opportunity to revitalize the local economy, and to revert the negative demographic trend, which very often characterizes those areas. However, apart from the scarce density of capital and human resources locally existing, the development of a biorefinery in those places strictly depends on the acceptance level of the local communities which, in assessing the socioeconomic and environmental implications, take into account a series of concerns particularly related to understand how their quality of life may change as a result of the industrial project implementation. These economic and social implications of the industrial use of renewable raw materials are discussed in Chapter 7. Potential markets for bioproducts are wide ranging, including polymers, lubricants, solvents, adhesives, herbicides, and pharmaceuticals. While bioproducts have already penetrated most of these markets to some extent, new products and technologies are emerging with the potential to further enhance performance, cost competitiveness, and market share. The market needs and opportunities for products produced by the existing and proposed new types of biorefineries are explained in Chapter 8. One major reason for the interest in biobased products is their potential contribution to the mitigation of climate change since biobased products are made from renewable resources which, during their growth, take up the same amount of CO2 as is released by biological degradation or energetic conversion in the end of the product’s life. This is a generic advantage compared to the use of fossil resources, which release the inventory of carbon accumulated and stored in the ground millions years before. However, is this true for all biobased products? Chapter 9 tries to answer this by discussing the life cycle analysis of biobased products. The aim of this book is to highlight all areas which have to be regarded in order to realize the vision of a “biobased economy” as a sustainable industrial future based on renewable resources is often termed. The choice of the chapters is inspired by the scientific framework and the business conditions with an influence on the development of a biobased economy. How do the different authors as specialists in their fields appraise the application of renewable raw materials? Where do they see chances, where do they see need of action? “May you live in interesting times” stated Wim Soetaert in regard to the progress of biorefineries (see Soetaert, W. [2009] May you live in interesting times! Biofuels, Bioprod. Biorefin., 3, 491–492, DOI: 10.1002/bbb.173). We hope that you will have interesting time while reading this book!
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2 Plants as Bioreactors: Production and Use of Plant-Derived Secondary Metabolites, Enzymes, and Pharmaceutical Proteins Peter C. Morris, Peter Welters, and Bernward Garthoff
2.1 Introduction
The organic chemical industry is largely based on materials derived from photosynthetically active organisms: plants (coal) and algae (petrol). In addition to these fossil sources, the chemical industry in Germany obtains 10% of its raw material from renewable resources, with more than 90% of these from plants. Due to dwindling fossil reserves, the focus of research has shifted to replace petrochemically derived chemicals by renewable plant-derived material. Initially the chemical industry considered fermentation of plant carbohydrates as the only viable solution. But now, with the increasing success of globally grown genetically modified (GM) plants, plant enzymes, cell cultures, and whole plants have been taken seriously for chemical production processes. Pharmaceutical proteins, small molecule drugs (SMDs) [1], and fine chemicals have been the first choice for production. But with ever-rising prices for fossil resources, chemical commodities such as platform chemicals (e.g., succinate, itaconic acid), intermediates, or polymers [2] are now considered as economically viable. This chapter will remind the reader that for all these new developments there are already examples of established production processes where plants, plant cell cultures, plant enzymes, or plant (secondary) metabolites play a major role. It will give examples where genetic modification of plants and the use of plant enzymes and ingredients have increased the economical and ecological potential of plants as renewable resources for a sustainable chemistry.
2.2 Renewable Resources in the Chemical Industry
The chemical industry is a raw material- and energy-intensive industry. Due to the scarcity of fossil resources, steadily increasing oil prices, and a need to reduce greenhouse gases, renewable resources from plants will be an increasingly important issue for the industry over the coming years. Germany, fourth in the world in Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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chemical production, will take a leading role in these efforts as manifested by high investments of the German chemical industry in industrial biotechnology R&D. Presently, around 10% of basic material for the chemical industry stems from renewable resources, mainly plant materials. The sustainability of chemical processes can be increased by the use of fermentation processes or direct biocatalytic steps. Unlike most chemical reactions, biocatalytically driven reactions are highly stereo-selective for the substrate and the resulting product due to the intrinsic properties of the enzyme activities, resulting in particularly high specificities for substrates and reactions. In addition, natural enzyme-based processes operate at lower temperatures and atmospheric pressure, and they produce less toxic waste than conventional chemical processes. As an example, the conversion of elemental nitrogen to ammonium demands high pressures and temperatures, and the use of metal catalysts in the Haber–Bosch process. In contrast, bacterial nitrogen fixation occurs at room temperature and normal pressure. Nitrogen fixation by freeliving bacteria is widespread, but the rate of fixation is relatively low (15 kg/ha/ year) as it is limited by the available energy. In contrast, nitrogen fixation rates from 75 to 300 kg of N/ha/year are common in various combinations of legume– rhizobia [3]. The production of aromatics in a sustainable fermentation process is a challenging future task where interdisciplinary skills and close cooperation of microbiologists and plant specialists will be necessary. The plant shikimate pathway, synthesizing anthranilate out of erythrose, serves as a prime example that is waiting to be converted into a fermentation process or a whole plant production via an interdisciplinary approach. Currently, however, it may be easier to use a waste compound from the forest industry to be converted by a simple chemical reaction into an aromatic compound (Figure 2.1). 2.2.1 Commodity Production
When polymers or commodity production in the chemical industry is considered, a tacit consensus is that plants cannot compete with petrochemically derived
Figure 2.1 Example of a waste product from forest industry being converted in a simple one-step chemical reaction into an aromatic compound (α-pinen into cymol; drawing by Dr. Frank Kastenholz, Phytowelt GreenTechnologies).
2.2 Renewable Resources in the Chemical Industry
products. But at a closer look, numerous examples where the chemical industry uses plant-derived materials on a large scale become obvious. For example, plant oils are already widely used as raw materials for the synthesis of a huge number of compounds. Fatty acids are used as lubricants, emulsifiers, agrochemicals, fragrances, and pharmaceuticals. The world production of plant fatty oils currently exceeds 130 million metric tonnes per annum [4] and plant oils are one of the most important sources for sustainable chemistry. Since glycerol and fatty acids, together with their methyl esters, are the basic oleochemical compounds in industry currently generated from crude oil by various chemical and biocatalytic processes, the transformation of plant oils and fats into oleochemicals by hydrolysis of natural triglycerides into glycerol and mixed fatty acids and/or fatty acid derivatives as well as purification of the released compounds represents a major progress in sustainability [5]. Optimized plant oils are of increasing importance for sustainable chemistry. In the future, the use of data mining will be increasingly important in order to obtain novel biocatalysts (enzymes) for the processing requirements of fats and oils with iterative modules of phytomining and in silico screening, which provides a straightforward approach for identification of biocatalysts and opens new production routes in sustainable chemistry. 2.2.2 Production Problems
A major problem for the use of natural plant-derived matter in the chemical industry occurs when molecules are under-functionalized because they have only one group that can be easily modified or used for chemical linkage formation. Especially fatty acid- or isoprene-derived molecules need the introduction of one or two functionalized groups. To address this problem, several successful attempts have been made to genetically modify plants to increase the content of specific fatty acids, either of longer chain length than the usual C16 to C18 [6–9], or with chain lengths below or equal to C10 to C12 [10, 11], or with special functional groups as in erucic acid [12]. Nearly every major seed or agro-biotechnology company (Table 2.1) has patents for the alteration of fatty acid composition, either to improve nutritional value for humans [7, 13], pigs [14], and fishes [15] or to comply better with industry standards [16]. For example, SemBioSys in Canada was able to produce safflower lines that are able to produce more than 60% of their oil content as α-linoleic acid, some lines even produced nearly 90% of their oil as α-linoleic acid [17]. An unusual example is where the production of branched or cyclic structures within a fatty acid molecule is proposed [18, 19]. The oxidation of the omega-methylgroup is of special interest because it opens the way to linear polymers such as polyesters or polyamids [20]. Enzymes executing this type of reaction belonging to the class of cytochrome P450 enzymes have been reported for the production of omega-hydroxy fatty acids and the biosynthesis of TAG-/DAGbased estolide polyesters in petunia stigma [21]. Very rich sources of omega-oxidized fatty acids are the protective polymers found in specific tissues
9
[EN] STABILIZED OLEOSOME PREPARATIONS AND METHODS OF MAKING THEM [EN] POLYUNSATURATED FATTY ACID PRODUCTION IN HETEROLOGOUS ORGANISMS USING PUFA POLYKETIDE SYNTHASE SYSTEMS
MONSANTO TECHNOLOGY LLC, US HARTNELL GARY F, US URSIN VIRGINIA M, US LUCAS DON, US SEMBIOSYS GENETICS INC, CA GUTH JACOB, US BOOTH JOSEPH, CA BEAZER MITCH, CA SHAFER KENT, CA MARTEK BIOSCIENCES CORP, US SEMBIOSYS GENETICS INC, CA METZ JAMES G, US KUNER JERRY M, US LIPPMEIER JAMES CASEY, US MOLONEY MAURICE MARTIN, CA NYKIFORUK CORY LEE, CA MONSANTO TECHNOLOGY LLC, US HARTNELL GARY F, US BAYER BIOSCIENCE NV, BE LAGA BENJAMIN, BE DEN BOER BART, BE LAMBERT BART, BE CANADA NAT RES COUNCIL, CA DOW AGROSCIENCES LLC, US ZOU JITAO, CA XU JINGYU, CA ZHENG ZHIFU, US
HARTNELL GARY F, US URSIN VIRGINIA M, US LUCAS DON, US
GUTH JACOB, US BOOTH JOSEPH, CA BEAZER MITCH, CA SHAFER KENT, CA
METZ JAMES G, US KUNER JERRY M, US LIPPMEIER JAMES CASEY, US MOLONEY MAURICE MARTIN, CA NYKIFORUK CORY LEE, CA
HARTNELL GARY F, US
LAGA BENJAMIN, BE DEN BOER BART, BE LAMBERT BART, BE
ZOU JITAO, CA XU JINGYU, CA ZHENG ZHIFU, US
WO002009097403A1
WO002009126302A2
WO002007106905A3
WO002009102558A2
WO002009007091A3
WO002009085169A2
[EN] DIACYLGLYCEROL ACYLTRANSFERASE 2 GENES AND PROTEINS ENCODED THEREBY …
[EN] BRASSICA PLANT COMPRISING MUTANT FATTY ACYL-ACP THIOESTERASE ALLELES …
[EN] AQUACULTURE FEED, PRODUCTS, AND METHODS COMPRISING BENEFICIAL FATTY ACIDS
[EN] METHODS OF FEEDING PIGS AND PRODUCTS COMPRISING BENEFICIAL FATTY ACIDS
[EN] NUCLEIC ACID CONSTRUCTS AND METHODS FOR PRODUCING ALTERED SEED OIL
MONSANTO TECHNOLOGY LLC, US VOELKER TONI, US FILLATTI JOANNE J, US BRINGE NEAL A, US ULMASOV TIM, US
VOELKER TONI, US FILLATTI JOANNE J, US BRINGE NEAL A, US ULMASOV TIM, US
WO002007095243A3
[DE] PFLANZENSAMENÖL [EN] PLANT SEED OIL [FR] HUILE VÉGÉTALE DE
BASF PLANT SCIENCE GMBH, DE REIN DIETRICH, DE SENGER TORALF, DE BAUER JOERG, DE
REIN DIETRICH, DE SENGER TORALF, DE BAUER JOERG, DE
WO002009130291A2
Table 2.1 Patents on oilseed transformation and alteration of fatty acid profiles. 10
2 Plants as Bioreactors
PIONEER HI BRED INT, US DU PONT, US SINGLETARY GEORGE W, US COALDRAKE PETER, US KRUMPELMAN PAULETTE M, US NUBEL DOUG, US SAUNDERS COURT, US TARCZYNSKI MITCHELL C, US ZHOU LAN, US Syngenta Participations AG, Basel, CH
UNIV STAVANGER, NO MOELLER SIMON GEIR, NO NAM-HAI CHUA, US WEBBER PHILIP MICHAEL TOTAL FRANCE, FR LIMAGRAIN AGRO IND, FR GONTIER ERIC, FR THOMASSET BRIGITTE, FR WALLINGTON EMMA, GB WILMER JEROEN, GB TOTAL RAFFINAGE DISTRIBUTION, FR DUHOT PIERRE, FR GONTIER ERIC, FR THOMAS DANIEL, FR THOMASSET BRIGITTE, FR MENARD MARC, FR
SINGLETARY GEORGE W, US COALDRAKE PETER, US KRUMPELMAN PAULETTE M, US NUBEL DOUG, US SAUNDERS COURT, US TARCZYNSKI MITCHELL C, US ZHOU LAN, US
Stiewe, Gunther, 32657 Lemgo, DE Pleines, Stephan, 32130 Enger, DE Coque, Marie, Aucamville, FR Gielen, Jan, Bouloc, FR
MOELLER SIMON GEIR, NO NAM-HAI CHUA, US
GONTIER ERIC, FR THOMASSET BRIGITTE, FR WALLINGTON EMMA, GB WILMER JEROEN, GB
DUHOT PIERRE, FR GONTIER ERIC, FR THOMAS DANIEL, FR THOMASSET BRIGITTE, FR MENARD MARC, FR
WO002005063988A1
DE102008028357A1
WO002009150435A1
WO002006087364A1
WO001999018217A1
[EN] METHOD FOR PRODUCING BRANCHED FATTY ACIDS USING GENETICALLY MODIFIED PLANTS
[EN] PLANT CYCLOPROPANE FATTY ACID SYNTHASE GENES AND USES THEREOF [FR] …
[EN] PLASTID TRANSFORMATION VECTORS ALLOWING EXCISION OF MARKER GENES …
[DE] Neues Hybridsystem für Brassica napus
[EN] ALTERATION OF OIL TRAITS IN PLANTS
2.2 Renewable Resources in the Chemical Industry 11
12
2 Plants as Bioreactors
of all higher plants. The suberins and cutins are composed of a wide variety of oxygenated fatty acids, for example, saturated omega-hydroxy fatty acids and alpha,omega-diacids [22]. The most common monomers in cutins are 10,16dihydroxy-C16 acid, 18-hydroxy-9,10-epoxy-C18 acid, and 9,10,18-trihydroxy-C18 acid. These monomers are produced in the epidermal cells by omega hydroxylation, in-chain hydroxylation, epoxidation catalyzed by P450-type mixed function oxidases, and epoxide hydration [23]. The composition and the enzymes involved in the process of suberins and cutins promise to be a rich source for reactions sought for industrial biotechnology to functionalize hydrophobic plant compounds. 2.2.3 Natural Rubber as Compared to Synthetic Rubber
For the chemical industry, the most useful derivative from the terpenoid family is natural rubber (NR), polyterpene. Global rubber consumption (both NR and SR) is forecasted to reach 24.3 million metric tons in 2010, with NR production of 10.2 million metric tons. In the longer term, global rubber consumption is predicted to reach 33.9 million metric tons by 2020, with NR production of 15.4 million metric tons. Global NR production is estimated to be 9.9 million tonnes at the end of 2008. Thus, nearly half of the global rubber production comes from plants. The main advantage of NR is the uniformity of the polyterpene molecule, rendering a unique uniformity to the polymer properties not achievable by chemical elastomer production [2]. Due to the superior properties of NR, a slightly higher price than for SR is acceptable by the market. Although rubber trees stem from Brazil, most NR comes from Asia. The Asian plantations that were started at the end of the 19th century were founded on a very small number of trees [24]. Therefore, the genetic variability is extremely small and it is feared that diseases, especially the pathogen Microcyclus ulei, the causative agent of South American leaf blight [25], may endanger productivity. Research for alternative rubber sources is being conducted, either to improve new varieties by breeding or genetic engineering to render them resistant to the most common diseases, or to find alternative plants such as guayule or Russian dandelion, suitable for production of equal quality and quantity of NR. The Russian dandelion Taraxacum koksaghyz is rich in secondary metabolites including NR (poly-cis-1,4-polyisoprene). Because alternative sources of rubber are becoming economically attractive, research into this subject has been rejuvenated [26] and recent progress has been made regarding the identification and manipulation of rubber biosynthesis genes and latex accessibility [27, 28]. However, further work is still needed as rubber trees render yields of up to 3000 kg/ha/year, whereas guayule yields 2000 kg/ha/year and Russian dandelion only 150–500 kg/ha/year. 2.2.4 Cellulose and Other Fibers
Each year photosynthetically produced cellulose (the most common organic compound on Earth) amounts to 1.3 billion tonnes. Cellulose is a polysaccharide
2.2 Renewable Resources in the Chemical Industry
consisting of a linear chain of several hundred to over ten thousand β(1→4) linked D-glucose units. About 33% of all plant matter is cellulose (the cellulose content of cotton is 90% and that of wood is 50%). For industrial use, cellulose is mainly obtained from wood pulp and cotton. It is mainly used to produce paper; cardboard and textiles. The natural fiber industries employ worldwide millions of people, especially in developing countries and their products are processed in many small and large industries. The promotion of the use of natural fibers as a CO2 neutral resource could contribute to a reduction of climate-endangering gases, and the year 2009 has been assigned by the UN to be the international year of natural fibers. Production of man-made fiber from cellulose (cellulosics), of which rayon accounts for by far the largest portion, was 3.5 million tonnes in 2008. Cotton production has grown steadily. It is estimated to reach 25 million tons in the season 2010/2011. Although cotton production has increased significantly over the last decades, it had not been able to keep pace with the growth of synthetic fiber production, which overtook in the mid-1990s. Nevertheless, planting of genetically engineered cotton plants has improved yield, especially in India. These significant increases of yield efficiency are already apparent when simple agricultural traits such as herbicide and insect resistance are employed (Figure 2.2). Together with genetic modifications to improve quality of the yarn [29, 30], cotton will increase its market share when these elite events hit the market [31]. 2.2.5 Paper Production
By far the major use of cellulose is in paper and cardboard production. In 2006 160 million tonnes of pulp were produced from 530 million m3 of wood. 95% of this was made from plantation wood. It is estimated by the United Nations Food
(a)
(b)
600
12000
500
10000
400
8000
300
6000
200
4000
100
2000
0
2001 2002 2003 2004 2005 2006 2007 2008 2009 Productivity
Figure 2.2 (a) Increase of productivity in
Indian cotton harvest, between 1982 and 1997 harvest grew from 200 kg to 300 kg/ha, since the introduction of GM-cotton in 2002
0
2002 2003 2004 2005 2006 2007 2008 2009 Cotton in total
Bt-cotton
productivity nearly doubled to 550 kg/ha; (b) out of 9.4 million ha cotton cultivation in India, nearly 8 million are planted with GM cotton.
13
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and Agriculture Organization (FAO) that by 2020 all wood uses will be covered by production from plantations on an area of 450 million ha which is around 15% of the whole forested area of today (3.5 billion ha). 50 million tonnes of lignin are produced each year as a by-product of paper production, only 2% is used for ligninderived products, 98% is burned for energy purposes. If this material could be used instead in chemical industry, one-sixth of today’s petrochemically produced chemicals could be replaced by renewable substances. Without reducing the amount of land used for food production, wood production would be able to replace all petrochemically derived material production if we learn how to use cellulose, hemicelluloses, and lignins in a proper way and to alter their properties according to the demands of clients of the chemical industry. With another 150 million ha of tree plantations, we would be able to replace all naphtha by renewable resources. One way to achieve this is to use plant-derived enzymes to introduce functionalities into plant materials such as fatty acids- and isoprene-derived materials (e.g., omega-oxidation of fatty acids) and use (plant) enzymes to modify overfunctionalized molecules like sugars or sugar-derived polymers such as cellulose, starch, and hemicellulose in a directed and controlled way. The third application for plant enzymes would be the depolymerization of lignin into its monomers (reducing complexity of plant-derived products) or using plant enzymes to be able to copy in vitro the complexity of plant molecules such as taxol, artemisin, vincristin, or campthothecin. Interesting technologies are already under development, for example the linear lignin production technology developed by CIMV in France. More of these technologies are to come and will improve the variety of biopolymers (Figure 2.3).
16 14 12 10 Petropolymer
8
Biopolymer
6 4 2 0 1900
1920
1940
1960
Figure 2.3 Number of newly developed polymers between 1900 and 2020 (prediction). Petrochemically derived building blocks had been mainly developed in the 1940s and 1950s of the 20th century. New biopolymers
1980
2000
2020
gained in importance in the 1990s and will be the leading innovation driver in polymer chemistry in the 21st century. Courtesy of Dr. Manfred Kircher, CEO of CLIB2021.
2.2 Renewable Resources in the Chemical Industry
In China, transgenic Bt poplar trees are already grown in large-scale field trials (300 ha). These trials are part of a reforestation program and aim to reforest an area of approximately 17 million ha by the year 2012. In addition to poplars, other forest trees such as eucalyptus, birch, spruce, and pine have been GM. In Germany, transgenic poplar trees had to be destroyed before they were able to flower and spread their pollen. Instead, Germany intends to increase economical value of poplar plants by improved methods of breeding, for example, somatic hybridization to increase biodiversity and combine properties of poplar species, which are difficult to cross (FNR, R&D project “Innovative Hybridpappeln – Schnelles Wachstum für Deutschland,” FKZ 22004105, funded by the German Ministry of Agriculture). 2.2.6 Starch Production
World production of starch in crop plants is estimated at 2.5 billion tonnes/year. The Chinese government is planning to double its starch grain production (especially rice) to 540 million tonnes by the year 2020 by genetic engineering of crop plants [32]. Starch is composed of a polymer of the sugar glucose. Despite its simple composition, starch has a complex structure, forming semicrystalline granules. The starch industry extracts starch from cereal grains and potatoes and processes it into several hundreds products, from native starches to physically or chemically modified starches, liquid, and solid sugars. Starch products are used as ingredients and functional supplements in food, nonfood, and feed applications. It also generates co-products that are sold into animal feed (e.g., wheat proteins, corn gluten feed) and food (e.g., wheat gluten). The total quantity of starch produced in Europe in 2008 was 9.4 million tonnes and the consumption of starch and starch derivatives (excluding co-products) in 2008 was 8.7 million tonnes – 39% of which were used for nonfood applications) (Table 2.2). One of the earliest known industrial uses of starch was to “size” and stiffen textiles. It is also added to yarns to increase mechanical strength and resistance to friction wear and helps resist moisture penetration. And it can serve as a stabilizer and filler for colored inks when fabrics are overprinted. The detergent industry uses starch products for the production of biodegradable, nontoxic and skinfriendly detergents. Starch products are also used in an array of less obvious applications: as feedstock in fermentation for the production of amino acids,
Table 2.2 Uses of starch in the European industry.
Confectionary Processed and drinks food
Corrugating and paper making
Pharmaceuticals Other nonfood Feed and chemicals
32% 2.78 Mio. t
28% 2.44 Mio. t
6% 0.52 Mio. t
29% 2.52 Mio. t
4% 0.35 Mio. t
1% 0.09 Mio. t
15
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2 Plants as Bioreactors
organic acids, and enzymes, and also by the chemical industry for the production of surfactants, polyurethanes, resins, and in biodegradable plastics. Starch is also used in the construction industry, for concrete admixtures, plasters, and insulation, as well as in oil drilling, mineral, and metal processing. The paper and board industries are the largest nonfood starch-using sector, using approximately 60% of the total industrial starch. Starch is also used quite extensively in cosmetics and health care products. One product made directly by the fermentation of starch, cyclodextrin, is especially interesting as a fermentation product. In 1998 the global market was estimated between 1800 and 3600 tonnes. As stated by the company, Wacker Chemie had at that time a production capacity of 3000 tonnes. Today, 10 years later, they have increased their production capacity to 7500 tonnes of cyclodextrins a year. These molecules are used as stabilizers and excipients in the pharmaceutical, life science, cosmetics, food, and agricultural industries. Potatoes are the world’s fourth largest food crop, following rice, wheat, and maize. The FAO reports that the world production of potatoes in 2009 was 330 million tonnes [33]. The world production of potato starch exceeds 2 million tonnes per annum. It is regarded as having superior properties to cereal starches and is the preferred starch for paper and pulp surface sizing, which accounts for more than 50% of the use in this particular industry. However, wheat and maize starch are usually used as they are a lower cost option. That might change now since a high amylopectin-containing GM potato got approval from the EU Commission. This potato, with the commercial name Amflora, contains almost only the amylopectin form of starch and will render the industrial use of it cheaper, as it is no longer necessary to separate amylose and amylopectin [34]. Another approach to make potato starch more valuable for industrial uses is to modify the amylose to give it new properties. To make use of starch as a fat-resistant packaging material a hydroxypropylated amylose has been developed by several industrial and academic laboratories independently (e.g., [35]). Another way to improve competitiveness is to improve pest resistance [36]. A Phytophthora resistant GM potato line [37, 38] is aimed at commercialization in 2014. A canker-resistant potato produced by somatic hybridization is under development by a consortium of potato breeders, academic institutes, and Phytowelt GreenTechnologies funded by the BMBF [39]. 2.2.7 Sugar Production and Improvement of Yield by Genetic Engineering
World sugar production for the 2009/10 marketing year is estimated at 153.5 million tonnes. Brazil, India, Thailand, and China account for 50% of world sugar production and 59% of world exports [40]. Sugar is the most widely used feedstock for industrial fermentation. The first transgenic sugar beet has been approved in the United States in 2005. In 2009 it had 90% of the US market share, although the legal status of this crop is at the time of writing under dispute [41]. Sugarcane, being a monocotyledonous plant, has been difficult to improve by plant transformation. First attempts are trying to render sugarcane disease resistant, herbicide
2.3 Fine Chemicals and Drugs
tolerant, and drought resistant [42]. A new research alliance has been established this year between BASF and KWS with the aim of improving yield by 15% by the year 2020, mainly through improvements in drought resistance.
2.3 Fine Chemicals and Drugs
The development of modern human culture was made possible due to the intensive use of plants and plant products as valuable sources for nutrition, commodities, and energy. However, only recently we have come to see plants as a cornerstone of sustainable industry by exploiting lead structures and biosynthetic pathways for the modification of plant-derived renewable resources. It is most important to note that usage of plant enzymes and their biosynthetic abilities is not restricted to the use of whole plant systems (e.g., as bioreactors). Through the targeted use of biotechnology and biodiversity, it is possible to isolate plant genes and optimize their coding regions to produce enzymes in microorganisms with specificities and stabilities tuned to particular industrial purposes. The rapid elucidation of biosynthetic pathways made in part possible through advanced genomic tools has made natural products again the molecules of choice for drug development. Indeed, half of the drugs currently in clinical use are natural products and it is expected that the market size of biotechnology-derived small molecules will exceed US$100 billion in 2010 and US$400 billion in 2030 [43]. 2.3.1 Plant Cell Culture
Plant-derived natural products have a high chemical diversity and function in a multitude of ways as flavor enhancers, agricultural chemicals, and most importantly, as human medicines. Securing the production of pharmaceutically active natural products has often been a challenge due to slow growth rates of some species, low yields found in nature, and unpredictable variability in accumulation [44]. However, especially in the case of very complex structures, chemical synthesis is economically impossible. Therefore, the optimization of plant cell culture not only by introducing and improving biosynthetic pathways by genetic engineering but also by optimizing culture conditions and purification schemes are applied to achieve a reliable production of pharmaceutical products. 2.3.2 Terpenoids
One of the best understood biosynthetic pathways for terpenoids is the biosynthesis for menthol in mint plants. All the enzymes are identified, cloned, and characterized [43]. Menthol plays an important role as aroma in food, cigarettes, and medications for the pulmonary tract and in cosmetics. Improvements of yield or
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quality of monoterpene production by genetic engineering were successfully tried but the market size is too small to be worth the amount of time and money expended for deregulation. Limonene as a by-product of orange juice production can be used for polymer production together with CO2 to form a polystyrol-like foam. Menthon can be used as a precursor for branched dicarbonic acids and alpha-pinen (a by-product of the forest industry) as precursor for cymol production or for enzymatic verbenone production. Other important terpenoids are phytosterols. They are used in the production of steroid hormones such as cortison or progesteron by Bayer Schering Pharma. Probably the most important example where plant secondary metabolism and microbial fermentation are synergistically combined, steroid hormones, are produced from phytosterols. A fermentation process by Bayer Schering Pharma uses a plant metabolite and converts it by a single-step microbial fermentation into the desired end product. 2.3.3 Amino Acids
The production of amino acids such as cysteine is sometimes made from plantbased raw materials in a fermentative production process [45]. Cysteine is a sulfurcontaining amino acid that is primarily used in the food industry, for example, for baked goods and flavored production, but it is also used for drugs and cosmetics. Since it is manufactured from purely plant-based and inorganic starting materials, it is also characterized as halal, kosher, and vegetarian-grade. This process has been nominated for the EU Commission’s European environmental prize competition and has received the Environmental Prize for Vegetarian Cysteine from the Federation of German Industries. But the main producer of amino acids by fermentation is Evonik Industries, who has established a sophisticated process where 14 different amino acids are currently produced in large-scale industrial production size by fermentation [46]. 2.3.4 Fatty Acid Derivatives
Photosynthetically active organisms are the only ones being able to synthesize tocopherols and tocotriols. These compounds are essential to mammalian organisms as precursors to vitamin E, and protecting polyunsaturated fatty acids from peroxidation. From the recent elucidation of their biosynthetic pathway [47], it is now possible to improve the vitamin E content of plants by genetic engineering, thus improving the nutritional value for food and feed purposes. Vitamin A is one of micronutrients in the focus of World Health Organization, FAO, and other organizations to be supplied in higher amounts to malnourished people in developing countries as key factors promoting health. The relevant programs include fortification of food, breeding of crops to improve content in plants already producing vitamin A precursor, or to introduce it in parts of plants where it does not
2.3 Fine Chemicals and Drugs
occur naturally in crop plants by genetic engineering [48]. Although carotinoid biosynthesis is regulated in a complex way, recent progress has resulted in the identification of lycopine-β-cyclase as a rate-limiting step in chromoplasts and has resulted in an increase of total carotinoid synthesis in tomatoes by 50% [49]. Enhanced vitamin A production in the endosperm of rice has been achieved already 10 years ago [50]. Commercialization in Asia, Africa, and Latin America to reduce the toll of vitamin A deficiency, mainly the blinding of 500 000 people yearly, has been fiercely fought against by anti-GM nongovernmental organizations, on the grounds of insufficient vitamin A yields. However, only 5 years later a rice variety has been presented with 23 times higher provitamin A (37 μg/g) content in the endosperm, that is, 500 g of genetically optimized rice would be sufficient to deliver the daily recommended dose of vitamin A [51]. 2.3.5 Plant Protection
Pyrethroids are a very potent class of insecticide naturally occurring in chrysanthemums. The cultivation of this plant in Africa is one of the main sources of this insecticide for biological agriculture. A synthetic analog is produced by the use of plant enzymes produced microbially in Escherichia coli. DSM uses the enzyme hydroxynitrilase to produce an intermediate of pyrethroid synthesis by fermentation (Figure 2.4). 2.3.6 Small Molecule Drugs
Until now, microorganisms such as fungi and bacteria (often extremophiles) were used as main sources for enzymes. The growing complexity of reactions required for the production of fine chemicals, especially for the pharmaceutical industry, has increasingly drawn the attention of industrial biotechnology to plants. The high complexity of plants’ secondary metabolism, as well as the fact that most of today’s small molecule drugs (SMDs) can be traced back to a plant metabolite as the basic structure, is certainly a major reason for this development. Moreover,
HCN
Hydroxynitrilase (Oxynitrilase) m-phenoxybenzaldehyde
(S)-m-phenoxybenzaldehyde -cyanohydrin
Figure 2.4 Example of a plant enzyme (Hydroxynitrilase from Hevea brasiliensis) used for
the synthesis of an intermediate in the production process of an insecticide (pyrethroid) by DSM.Drawing by Dr. Guido Jach, Phytowelt GreenTechnologies GmbH.
19
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2 Plants as Bioreactors (a)
(b)
Figure 2.5 Trichomes of mint plants (a) and resulting phenotype of a somatic hybridization (b, hybrid) between mint varieties (b, E33, E87: leaves of parent lines used for protoplast fusion, unpublished results E. Baumann, Phytowelt GreenTechnologies GmbH).
nature has optimized plant enzymes to work best at relatively low temperatures. Their use therefore opens new chances for energy reduction in novel industrial applications. Besides their unmatched range of biosynthetic pathways and reaction mechanisms, plants have found during their evolution unique possibilities to produce, store, and enrich even highly toxic substances by compartmentation in specialized cell organelles or special tissues like trichomes in mint species (Figure 2.5). As most secondary metabolites are only made in low amounts and are often found in wild-type plants not optimized for cultivation, supply of the desired molecule is often limited or at least very costly. To overcome this bottleneck, different ways have been developed to produce important metabolites or precursors in cell cultures, tissue cultures, or in higher amount in whole plants [44]. Paclitaxel (an anticancer agent) is one of these substances with high commercial value where independently established suspension cultures of genetically engineered plant cells have been patented as production process [52, 53]. The plant-derived drug artimisin (and derivatives) are used to combat malaria. Instead of using plant cell culture to get easier access to the finalized product, attempts to bring the whole biosynthetic pathway of artimisin from plants into microbes are on their way. The first trials to use plant enzymes in microbes used the enzyme amorphadiene synthase from Artemisia annua in E. coli to produce amorphadiene, a precursor of artemisin with a concentration of up to 24 μg/l culture [54]. Since then, it has been possible to produce artemisinic acid in yeast by bringing a CYP71 family P450 enzyme plant gene encoding the amorphadiene oxydase from A. annua into expression in Saccharomyces cerevisiae, yielding up to 100 mg/l culture [55] (Figure 2.6). A completely different approach has yielded plants with a higher amount of artemisinin. Made possible by the rapid falling cost of genome sequencing, a sequence-based quantitative trait loci (QTL) marker breeding approach (deep sequencing of the transcriptome) has been successfully used to raise the artemisinin concentration in A. annua up to 2% dry mass [56], more than four times of the best value so far published by Chinese sources [57].
2.3 Fine Chemicals and Drugs Engineered mevalonate pathway 2
Acetyl-CoA DMAPP
OPP +
OPP IPP
IspA H ADS H Amorphadiene
PPO FPP
3-step oxidation H
H Reduction HO H O Artemisinic acid
hν, O2
Chemical synthesis
O O O H O
H
O Artemisinin
Microbial biosynthesis Figure 2.6 The transfer of a cytochrome P450 enzyme (CYP71 family amorphadiene oxidase)
from A. annua brought the synthesis three steps closer from amorphadiene to artemisinic acid which could then be used for chemical synthesis of artemisin ([55], drawing from [58]).
Combinatorial biosynthesis, that is, the combination of metabolic pathways in different organisms on a genetic level allowing the use of precursors of the host cells is another promising strategy for the synthesis and industrial production of important classes of natural products, including alkaloids (vinblastine, vincristine), terpenoids (artemisinin, paclitaxel), and flavonoids [59]. Increasing the concentration of the alkaloid scopolamine in medicinal plants has been the target of much research. First results were obtained in the late 1980s when somatic hybridization was used to increase the content in Datura species, and the transformation of Atropa belladonna with the enzyme hyoscyamine-6-betahydroxylase lead to a shift from hyoscyamine to a nearly exclusive production of scopolamine (Figure 2.7) [60]. Another alkaloid whose production has been successfully improved by genetic engineering in plant cell culture and whole plants is benzylisoquinoline. This was done in poppy plants and cell cultures by RNAi inhibition of the berberine bridge enzyme, which resulted in the production of reticuline [61]. The same enzyme was also targeted in an approach to transfer the benzylisoquinoline alkaloid production from tyrosine in the Papaveraceae, Berberidaceae, Ranunculaceae, Magnoliaceae, and other plant families into microorganisms [62]. Its transfer in yeast resulted in the
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2 Plants as Bioreactors
Figure 2.7 Enzymatic conversion of Hyoscyamine into Scopolamine by Hyoscyamine-6-betahydroxylase. Drawing by Dr. F. Kastenholz, Phytowelt GreenTechnologies GmbH.
production of (S)-scoulerine. Magnoflorine, an antibacterial agent like palmatine and berberine, could be produced by the transfer of two other enzymes, one being a cytochrome P450 enzyme from plants. In E. coli, (S) and (R)-reticuline could be produced from dopamine [63] (Figure 2.8). (S)-reticuline has a potential as cardioprotective compound probably due to its vasorelaxant effects by inhibiting Ca2+channels [64]. 2.3.7 Polyphenols and Resveratrol
Polyphenols are reported to improve human health by a variety of mechanisms. Therefore, their reliable production in microorganisms is of special interest [65]. For example, resveratrol has been identified as an active ingredient of red wine underlying the so-called French paradox. Despite eating fat-rich food, people from Southern France suffer less from cardiac diseases than do people from Northern Europe. One of the effects appears to be the reduced clogging capacity of blood platelets in the presence of resveratrol. Although, it seems that the surplus of the European wine industry should be able to cover the demand and other plant sources such as mulberry are known, production of resveratrol in fermentation of microorganisms has been successful in yeast and E. coli by introducing two genes from plants (4CL and STS stilbene synthase [43]).
2.4 Plant-Made Pharmaceuticals
Plants lend themselves readily to the large-scale production of pharmaceutical proteins and peptides, termed plant-made pharmaceuticals, (PMP) for both human and animal applications, as this approach has the important advantages of simplicity of production, cheaper costs, and the lack of zoonitics (animal pathogens or retroviruses, prions) or bacterial endotoxins. The use of a eukaryotic host base
these microorganisms, from [63]. MAO: overexpressed mono-amine oxidase from E. coli, NCS: norcoculaurine synthase, MTs: specific O- and N-methyltransferases, BBE: berberine bridge-forming enzyme, CYP80G2: diphenyl ring bridging enzyme.
Figure 2.8 Production of alkaloids by enzymatic conversion of amino acids in plant cell, yeast, and E. coli by transfer of plant biosynthetic enzyme genes into
2.4 Plant-Made Pharmaceuticals 23
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permits the majority of mammalian-compatible post-translational protein modifications (reviewed, [66, 67]). The most prevalent recombinant pharmaceutical proteins produced in plants are vaccines and monoclonal antibodies, but enzymes, hormones, and growth factors can also be made. 2.4.1 Vaccines
Vaccines are used to elicit a protective immune response without the accompanying disease process, and single proteins specific to pathogens (subunit vaccines) are increasingly used for this purpose, usually being administered by injection to induce a systemic immune response, but when these are administered orally, they can elicit IgA in the mucosa, an important route for pathogen ingress. The concept of using plants to produce vaccines is particularly attractive not only because of the advantages of plants outlined above, but additionally because vaccines can be grown in situ, and this together with oral administration removes the need for cold conservation of a purified protein, although accurate dosage of the vaccine may be an issue when using raw plant material. Production in seed crops (maize, rice, barley, soy) may permit long-term storage (years) at ambient temperatures. Additionally, because an unpurified plant-produced vaccine is contained within the plant cell, the unpurified antigen is protected to an extent from digestion so that oral administration can also induce systemic IgG production (reviewed, [67–69]). The first instance of a vaccine being made in plants was in 1990 when a patent was filed for a Streptococcus mutans protein (SpaA) expressed in tobacco. Since then, many other vaccines (e.g., cholera toxin B, Hepatitis virus surface antigen, Plasmodium surface protein) have been produced, and multiple different plant species (e.g., tomato, potato, banana, and rice) have been used, particularly as an edible host is needed for oral administration. An important scientific milestone was when the E. coli heat labile enterotoxin (LT-B) was expressed in potatoes and was shown to be orally immunogenic when 5 g of transformed tuber was fed to mice over 18 days [70]. However how this might translate to an effective dose in humans is not yet established. Numerous other workers have since demonstrated for animal models that oral or injected immunization with plant-produced antigen would provide protection against diseases such as Yersinia pestis [71], or Avian Influenza Virus [72]. An exciting possibility afforded by this technology is the ability to produce HIVspecific antigens, for example, the HIV proteins Tat, Gag, and Nef. However, although antigen production has been achieved, protection against HIV has not been demonstrated [73, 74]. A process termed oral immune tolerance causes a reduction in the peripheral response to an antigen when that antigen is presented orally. This is the basis of an experimental approach to treat type-I diabetes, in which there may be an autoimmune reaction against the blood glucose regulating hormone, insulin.
2.4 Plant-Made Pharmaceuticals
Cholera toxin (including the nontoxic B chain, CTB) is a potent immune response adjuvant, and fusion of antigens to CTB enhances the binding and effectiveness of antigens. An insulin-CTB fusion protein produced from bacteria has proved difficult to purify, however potato-based expression of such a fusion protein has been successful and oral administration shown to reduce inflammation of the pancreas in diabetic mice [75]. However, despite all these advances and advantages, there is currently no plantderived recombinant vaccine in clinical trials beyond phase I, although a chicken Newcastle Disease virus vaccine has been approved for sale in the United States but is no longer sold by the company [76]. 2.4.2 Monoclonal Antibodies
Medical monoclonal antibody production is a multi-billion dollar industry and at the forefront of modern medicine. They can be used for diagnostic or for treatment purposes. Such antibodies are usually produced in mammalian hybridoma cells, which are expensive to grow and harvest ($10 000/g purified protein). By contrast, it is estimated that recombinant plant-produced antibodies may cost one-tenth of that to produce, and less if expression levels are high enough. The first instance of antibody production in plants (plantibodies) was in 1989 [77], and many other examples of plant produced antibodies directed against antigens of medical relevance, including different types of antibodies (IgA, IgG, IgM) have followed (reviewed) [69, 78, 79]. Antibodies are heavily glycosylated, and, as noted below, the pattern of glycosylation in plants does differ from that in mammals; but this is reported not to affect antigen-binding properties [80]. Mammalian antibodies consist of two protein chains, the heavy and the light chain, thus for full-size antibodies, both proteins must be co-expressed and assembled in the plant cell, which is made possible by the similarity of protein-processing mechanisms in plants and mammals. Alternatively, simpler, single-chain antibodies can be expressed. These consist, for example, of a fusion of the variable regions of the heavy and light chains (scFv form antibodies), as has been done for a mouse B-cell lymphoma, which conferred protection against the original lymphoma [81]. A well-documented example of a plant-produced antibody is the tobacco expressed secreted form of the Guy’s 13 antibody directed against the adhesion protein of caries-causing S. mutans, which yielded 500 μg recombinant protein per gram fresh weight. This plant-derived antibody successfully prevented oral colonization by S. mutans in a human trial [82]. Other examples of therapeutic and diagnostic plantibodies include those directed against cancer epitopes, such as carcinoembryonic antigen and colon cancer surface antigen. An anti-herpex simplex virus (HSV) antibody made in soybeans has been shown to prevent HSV transmission in animal models [83]. Again, despite this promise, currently only one PMP monoclonal antibody is approved for use, CB-Hep1, that is used in the manufacture of a hepatitis vaccine in Cuba.
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2.4.3 Other Therapeutic Proteins
PMPs are not restricted to vaccines and antibodies. There are a number of enzymes with medicinal applications that have been produced in plant cells, such as gastric lipase (for the treatment of cystic fibrosis), lactoferrin, and lysozyme (both with antibacterial properties). These latter two have been found in trials to aid recover from childhood diarrhea [84]. A number of human growth factors and cytokines, proteins that regulate cell division and differentiation have also been expressed in plants. Examples include: human somatotropin, a growth hormone [85]; epidermal growth factor, an important regulator of mammalian cell growth and division [86]; granulocyte-macrophage colony-stimulating factor, which promotes white blood cell production [87]; erythropoietin, a regulator of red blood cell production [88]; and interleukins, important facilitators of the immune system, which were expressed in tobacco suspension culture cells and secreted into the medium [89]. An important target for PMP production is insulin. This small protein is essential for regulation of glucose uptake from the blood, and increasing numbers of people suffer from type-I diabetes (0.7% of the global population), characterized by insufficient or nonfunctional insulin, and treatable by insulin injection. Currently, most therapeutic insulin (5 tonnes/year) is bacterially produced recombinant protein. The protein consists of two chains held together by two disulfide bridges. Production of insulin in plant cells has been a technical challenge but by targeting an oleosin–insulin fusion protein to oil bodies of Arabidopsis seeds, active insulin at commercially relevant levels could be recovered (1.15% of total seed protein). As is the case for prokaryotically produced insulin, the precursor protein was cleaved with trypsin to produce the two peptide chains [90]. This proof of principle experiment has been followed up by SemBioSys Genetics, who have expressed insulin in the crop Safflower, and medical trials are currently underway. 2.4.4 Methodologies for PMP Production
To produce foreign proteins in plants, it is necessary to first introduce appropriate coding DNA into the plant, and there are two different approaches to this [67]. Either, plants can be stably transformed by means of Agrobacterium tumefaciens or by direct DNA uptake (biolistics, for example) so as to express the desired product. This method has the advantage that it is possible, by use of the appropriate promoter, to target expression to specific organs (leaves, roots, seeds), and once an appropriate transgenic plant has been produced, production can be scaled up in principle without limit; yields of tobacco biomass can potentially exceed 100 tonnes/ha [91]. Another option is to allow the recombinant protein to be released into the medium in hydroponic growth systems. However stably transformed plants may take time to generate and levels of expression in stably transformed
2.4 Plant-Made Pharmaceuticals
plants tend to be relatively low (less than 1% of soluble protein). Targeting of the recombinant protein to different cellular compartments may enhance yields; for example, scFv antibodies are stabilized if fused to the KDEL endoplasmic reticulum targeting signal [92]. Transformation of the plastid genome [93], although technically difficult, is reported to enhance protein yields considerably, although posttranslational modifications such as glycosylation will not be processed in a typical eukaryotic manner. Plastid transformation has the added advantage of preventing gene transfer through pollen, so biosecurity is enhanced. An interesting study on the different measures employed for enhancement of protein expression is for the Nef protein, a conserved HIV accessory protein implicated in high HIV viral loads. In initial experiments, full-length cytosolic localized Nef was produced at only low levels in tobacco plants. Expression of a cytochrome b5-Nef fusion protein, which results in the protein being anchored in the ER membrane enhanced protein production threefold, although targeting Nef to the ER lumen (by means of a KDEL signal peptide) caused Nef to be degraded. However, fusion of Nef to zeolin, a maize ER located protein that normally forms protein bodies, resulted in recombinant protein at a level of 1.5% of total leaf protein. The highest levels of recombinant Nef were found when the Nef gene was transformed into the chloroplast genome. The level of recombinant proteins in such plants was reported as being up to 40% of the total leaf protein [74]. Alternatively, a transient transformation approach can be taken, in which plants are not permanently transformed, but are infiltrated with vectors containing the DNA constructs, resulting in the rapid production of high levels of recombinant protein. This has the advantages of speed and controllability although scale-up is limited. Transient transformation has been performed using viral vectors such as tobacco mosaic virus (TMV)-based systems or by using the bacterium A. tumefaciens, in conjunction with suppressors of posttranslational gene silencing. TMVbased systems have been shown to produce recombinant proteins up to 5 mg/g leaf fresh weight (up to 80% of soluble protein). One caveat is that most viral vectors can only accommodate small DNA inserts of about 1 Kbp. A combination of the two transient transformation approaches in which viral vectors are delivered into plants via Agrobacterium infection (so-called magnifection) is reported to be much more efficient and has been used to produce full-size IgG antibodies at 500 mg/kg of plant mass [94]. Over the years, technological modifications have been made to optimize expression levels or to ease extraction and processing, and now in principle plant-derived proteins can be produced in high quantities in the field or under glass (potentially up to 20 kg/ha). As plants do not have the complex logistical problems of growing bacteria in fermenters (the plant takes the place of the bioreactor), they are inherently a cheaper option to produce pharmaceutical proteins. Given the nature of PMPs, it is critical that they do not enter animal or human food chains. The importance of this problem was illustrated by attempts to market the recombinant protease trypsinogen by the ProdiGene company. This was achieved by expressing the protein in maize, and a 400 acre trial resulted in sufficient trypsinogen to warrant full-scale production. However, the presence of transgenic volunteer
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plants in the field in the subsequent year resulted in contamination of a (normal) soybean crop with recombinant protein-containing maize seeds. The soybean crop had to be destroyed and ProdiGene was fined a substantial sum by the USDA. Use of plants that are not in animal or human food chains (the most common example is tobacco) ensures that feedstocks cannot be contaminated. However, it may sometimes be important to express PMPs in edible crops if oral vaccines are to be produced. If yield is the primary criterion, then storage organs such as roots and tubers may be considered. Importantly, since plants are eukaryotic, they can carry out many of the same kind of posttranslational modifications to therapeutic proteins as takes place in mammalian cells. However, this is not always the case; for example, N-glycosylated proteins from plants show structural differences in their N-glycans, and these plant N-glycans may indeed be immunogenic, as has been demonstrated for the expression of a bean alpha amylase inhibitor in peas [95]. Mutation of glycosylation sites so as to prevent Nglycosylation is one approach to this problem, as is retention of the protein in the ER through a KDEL retention signal, because the ER lumen proteins show a glycosylation pattern more similar to that of mammals. A more complex strategy is to express mammalian glycosyltransferases in plants. A key target for PTM of PMP is addition of sialic acid to glycoproteins, but effective protein sialylation in plants remains a goal for the future. Progress has already been made in this direction, as Greenovation has a patent showing sialylation of glycoproteins in the moss Physcomitrella. Perhaps the greatest challenge for PMP production and commercialization is not technical, but sociological, and that is public acceptance of products from GM plants. However an encouraging sign is the recent commitment by Pfizer to commercialize plant-produced glucocerebrosidase for treatment of Gaucher’s disease [96].
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2 Plants as Bioreactors 77 Hiatt, A., Cafferkey, R., and Bowdish, K. (1989) Production of antibodies in transgenic plants. Nature, 342, 76–78. 78 Stoger, E., Sack, M., Fischer, R., and Christou, P. (2002) Plantibodies: applications, advantages and bottlenecks. Curr. Opin. Biotechnol., 13, 161–166. 79 Ma, J.K., Drake, P.M., Chargelegue, D., Obregon, P., and Prada, A. (2005) Antibody processing and engineering in plants, and new strategies for vaccine production. Vaccine, 23, 1814–1818. 80 Ma, J.K., Hiatt, A., Hein, M., et al. (1995) Generation and assembly of secretory antibodies in plants. Science, 268, 716–719. 81 McCormick, A.A., Kumagai, M.H., Hanley, K., et al. (1999) Rapid production of specific vaccines for lymphoma by expression of the tumor-derived single-chain Fv epitopes in tobacco plants. Proc. Natl. Acad. Sci. USA, 96, 703–708. 82 Ma, J.K., Hikmat, B.Y., Wycoff, K., et al. (1998) Characterization of a recombinant plant monoclonal secretory antibody and preventive immunotherapy in humans. Nat. Med., 4, 601–606. 83 Zeitlin, L., Olmsted, S.S., Moench, T.R., et al. (1998) A humanized monoclonal antibody produced in transgenic plants for immunoprotection of the vagina against genital herpes. Nat. Biotechnol., 16, 1361–1364. 84 Zavaleta, N., Figueroa, D., Rivera, J., Sanchez, J., Alfaro, S., and Lonnerdal, B. (2007) Efficacy of rice-based oral rehydration solution containing recombinant human lactoferrin and lysozyme in Peruvian children with acute diarrhea. J. Pediatr. Gastroenterol. Nutr., 44, 258–264. 85 Staub, J.M., Garcia, B., Graves, J., et al. (2000) High-yield production of a human therapeutic protein in tobacco chloroplasts. Nat. Biotechnol., 18, 333–338. 86 Bai, J.Y., Zeng, L., Hu, Y.L., et al. (2007) Expression and characteristic of synthetic human epidermal growth factor (hEGF) in transgenic tobacco plants. Biotechnol. Lett., 29, 2007–2012. 87 Sardana, R., Dudani, A.K., Tackaberry, E., et al. (2007) Biologically active human
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GM-CSF produced in the seeds of transgenic rice plants. Transgenic. Res., 16, 713–721. Matsumoto, S., Ikura, K., Ueda, M., and Sasaki, R. (1995) Characterisation of a human glycoprotein (erythropoietin) produced in cultured tobacco cells. Plant Mol. Biol., 27, 1163–1172. Magnuson, N.S., Linzmaier, P.M., Reeves, R., An, G., HayGlass, K., and Lee, J.M. (1998) Secretion of biologically active human interleukin-2 and interleukin-4 from genetically modified tobacco cells in suspension culture. Protein Expr. Purif., 13, 45–52. Nykiforuk, C.L., Boothe, J.G., Murray, E.W., et al. (2006) Transgenic expression and recovery of biologically active recombinant human insulin from Arabidopsis thaliana seeds. Plant Biotechnol. J., 4, 77–85. Tremblay, R., Wang, D., Jevnikar, A.M., and Ma, S. (2010) Tobacco, a highly efficient green bioreactor for production of therapeutic proteins. Biotechnol. Adv., 28, 214–221. Gomord, V., Denmat, L.A., FitchetteLaine, A.C., Satiat-Jeunemaitre, B., Hawes, C., and Faye, L. (1997) The C-terminal HDEL sequence is sufficient for retention of secretory proteins in the endoplasmic reticulum (ER) but promotes vacuolar targeting of proteins that escape the ER. Plant J., 11, 313–325. Daniell, H., Chebolu, S., Kumar, S., Singleton, M., and Falconer, R. (2005) Chloroplast-derived vaccine antigens and other therapeutic proteins. Vaccine, 23, 1779–1783. Marillonnet, S., Thoeringer, C., Kandzia, R., Klimyuk, V., and Gleba, Y. (2005) Systemic Agrobacterium tumefaciensmediated transfection of viral replicons for efficient transient expression in plants. Nat. Biotechnol., 23, 718–723. Prescott, V.E., Campbell, P.M., Moore, A., et al. (2005) Transgenic expression of bean alpha-amylase inhibitor in peas results in altered structure and immunogenicity. J. Agric. Food Chem., 53, 9023–9030. Ratner, M. (2010) Pfizer stakes a claim in plant cell-made biopharmaceuticals. Nat. Biotechnol., 28, 107–108.
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3 World Agricultural Capacity John K. Hughes
3.1 Petrochemicals Today
The modern chemical industry relies heavily on petroleum as a feedstock for the production of bulk and specialty chemicals. Although transport fuel and electricity generation remain the primary uses of fossil oil, chemical production accounts for a significant proportion of refinery output. In the UK, petrochemical production accounts for around 6% of oil consumption [1] and it has been suggested that the petrochemical industry consumes 10% of global mineral oil output [2, 3]. Therefore, as much as 360 million tonnes of oil could have been used for the production of chemicals in 2008 [4]. It is clear that chemical manufacturing represents a major direct use of nonrenewable petroleum. During the past century, petrochemicals have become a vital part of industrial and economic activity around the world. Synthetic polymers are an important part of numerous industrial products, consumer goods, and healthcare applications. Materials such as polystyrene, polyester, and polyvinyl chloride are used in an enormous range of products across a wide variety of market sectors [5]. Textile production, food packaging, construction materials, and communication and entertainment technologies are all reliant on a plentiful supply of plastics. Petrochemicals have also been used extensively as food preservatives, vitamin supplements, refrigerants, antifreeze solutions, cosmetics, detergents, pharmaceuticals, and disinfectants. Chemicals derived from oil have enormous industrial, economic, and social importance. Production of crude oil is increasing, but the rate of growth in extraction has slowed in recent years (Figure 3.1). Population growth, increasing wealth, and growing consumer demand in both developed and developing nations mean that demand for petroleum continues to increase. The resulting depletion of key fossil resources means that alternative sources of energy and raw materials will be vital for the sustainability and stability of the global economy. The overwhelming evidence for the impact of fossil carbon on the environment and climate shows the social and ecological importance of developing new and sustainable sources of raw materials. This chapter discusses the ability of agriculture to supply renewable raw Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
3 World Agricultural Capacity 4000 3500 3000
Oil (million tonnes)
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Figure 3.1 Global mineral oil production [4].
materials to the chemical industry. The potential contribution of modern agriculture will be evaluated and the scope for increased production of chemical products will be assessed.
3.2 Renewable Chemicals 3.2.1 Traditional Uses
Petroleum is the dominant feedstock for the modern chemical industry. However, renewable raw materials are still preferred in those sectors where substances derived from biomass provide higher quality or more cost-effective products. Examples include the use of wood pulp for paper production, cotton production for textiles, the use of linseed oil for surface coatings and linoleum, and the use of coconut and palm oils for detergents and soaps [6]. In each of these cases, there is no economically viable synthetic alternative of equivalent function. However, in contrast to petrochemical products, these remain relatively niche, specialist materials. Cotton fibers perform well as part of a fabric, but are of little use in other materials. If agriculture is to supply a larger part of the chemical industry, it must be capable of providing generic chemical building blocks that can be used in a wider variety of applications. 3.2.2 Potential Raw Materials
Several recent research projects have examined the potential of biomass as a renewable source of bulk chemicals. The BREW project has provided an exhaustive study of potential chemical precursors that can be produced from biological
3.2 Renewable Chemicals Table 3.1 Examples of the most promising biomass-derived chemical building blocks identified by both the BREW project and the US Department of Energy [5, 7].
Chemical product
Carbon number
Raw material
Production route
Acetic acid Ethanol Glycerol Lactic acid Propionic acid Aspartic acid Itaconic acid Succinic acid Glutamic acid
2 2 3 3 3 4 4 4 5
Ethanol and sugars Carbohydrates Oils Carbohydrates Glycerol and sugars Carbohydrates Carbohydrates Carbohydrates Carbohydrates
Fermentation Fermentation Chemical Fermentation Fermentation Fermentation Fermentation Fermentation Fermentation
sources [7], and the US Department of Energy has performed a thorough evaluation of likely high-value biological chemicals [5]. The key findings of these two research programs are shown in Table 3.1. Direct use of agricultural products as raw materials is rare. The majority of the chemical building blocks identified by these projects are derived from agricultural products using either chemical processes or microbial fermentation. Consequently, the primary raw materials required from agriculture are starch, sugars, and oils. These generic substances can then be used to manufacture a wide variety of more useful chemical products. In some cases, multiple products may be produced from a single agricultural feedstock. For example, glycerol is a by-product of the transesterification of plant oils during biodiesel production. Another potential biomass feedstock for bulk chemical production is lignin [8]. The indigestible nature of lignin means that it is not generally considered an agricultural product and indeed food production often occurs on land cleared of lignin-rich, woody vegetation. However, lignin contains a wide range of phenolic and aromatic hydrocarbon compounds that are of interest to chemists. Emerging technologies involving the fermentation, gasification, or pyrolysis of lignin and cellulose may allow the conversion of wood to oils and other useful organic chemicals. The nascent state of the conversion technologies, the present lack of dedicated wood biomass crops, and the uncertain availability of land for cultivation make the potential contribution of lignin to the chemical industry very difficult to predict. Although wood is readily available from established forest land, the impact of large-scale deforestation on biodiversity and the global carbon cycle may make this an undesirable source of biomass. Therefore, this chapter focuses on the more established starch, sugar, and oil crops. 3.2.3 Scope for Substitution
Petroleum and biomass are very different raw materials. Fossil oil consists of long-chain hydrocarbons formed under high temperatures and enormous pressures over many millions of years. In contrast, biological material is the product
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of recent anabolic activity – processes catalyzed by enzymes within living tissues. The chemicals present in biomass comprise a wide variety of highly oxygenated compounds, including acids, alcohols, proteins, and carbohydrates. Consequently, the most readily available renewable materials are not always directly analogous to the most readily available petrochemical compounds and so biomass itself does not represent a direct substitute for mineral oil. Although it is theoretically possible to produce identical molecules from renewable raw materials, where conversion pathways are complex or energy demands are high, it may not be economically viable to do so. In other cases, renewable materials may offer valuable functional advantages over their petrochemical counterparts. For example, polylactic acid (PLA) is a starch-derived polymer suitable for use in food packaging. In addition to being a renewable material, PLA is biodegradable and so provides an added advantage over petrochemical materials during waste disposal. These factors mean that direct substitution of a petrochemical product with a renewable chemical product is unlikely. However, production of identical molecules may be economically viable where there are direct financial incentives for producing renewable materials. For example, materials might be marketed as higher value “green” products or they may qualify for subsidies or credits due to any associated greenhouse gas saving. Changes in policy, technology, and consumer demand make it very difficult to determine the likely future industrial requirement for renewable chemicals.
3.3 Agricultural Production 3.3.1 Current Situation
The primary purpose of agriculture is food production and has been so throughout human history. During the last decade, environmental and economic concerns have led to growing interest in fuel and energy crop production. Therefore, the production of renewable chemicals from agricultural raw materials will be in direct competition with both food and fuel production for space, resources, labor, and funds. Although the high value of chemical products may make them economically viable, they may have an undesirable competitive effect on food production. However, food, fuel, and chemical production are not necessarily mutually exclusive. The biorefinery concept aims to make best use of whole-crop plants by producing numerous products from a single resource. For example, both the production of biodiesel from oilseed rape and the production of ethanol from carbohydrate crops by fermentation result in a protein-rich by-product. These can be used as feed supplements for livestock, reducing the need for dedicated animal protein crops such as soybean. This approach is still likely to divert some primary production away from food production and should not be seen as a complete solution to the impact of industrial use of crops on food supply.
3.3 Agricultural Production
Section 3.2.2 identified starch, sugars, and oils as the three agricultural products most useful as raw materials for the chemical industry using established processing and conversion technologies. As staple food products, these are already produced on a massive scale worldwide. Cereal crop cultivation for the production of starch as a source of dietary carbohydrate accounts for the vast majority of arable farming. In 2007, more than 2.3 billion tonnes of cereals were produced on approximately 700 million hectares of land. Wheat, maize, and rice are the dominant crop species, together accounting for 75% of the global cereal area. The total area used for cereal cultivation has remained relatively static over the last 50 years (Figure 3.2). However, significant increases in yield (Figure 3.3) means that total cereal production has more than doubled in the period since 1960 (Figure 3.4).
800
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Figure 3.2
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Global total area of major crop types [9].
4 3.5
Average yield (t/ha)
3 2.5 Cereals
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Figure 3.3
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Global average yield of major crop types [9].
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Production (million tonnes)
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Figure 3.4 Global total production of major crop types [9].
Oilseed crops were grown on approximately 250 million hectares in 2007. In contrast to cereals, the area of land used for oilseed cultivation has doubled over the last 50 years (Figure 3.2). This, together with a doubling in average yield (Figure 3.3), has contributed to a fourfold increase in raw oilseed production (Figure 3.4) and extracted vegetable oil output since 1960. Soybean and oilseed rape are the most important oil crops by area, accounting for 36% and 12% of the total oilseed area, respectively. However, these temperate crops have lower oil yields than tropical palm oil. Consequently, palm, soybean, and oilseed rape dominate global vegetable oil production, accounting for 30%, 28%, and 13% of vegetable oil production, respectively [9]. Sugar production occurs on a much smaller scale than cereal or oilseed production. The primary sugar crops are tropical sugarcane and temperate sugar beet. Around 28 million hectares were used for sugar crop production in 2007 and there has been a modest but steady increase in the global sugar crop area since 1960 (Figure 3.2). Sugar beet has seen a decline in area as a greater proportion of sugar has been obtained from more efficient sugarcane crops. Around 1.8 billion tonnes of sugar crops were produced in 2007 (Figure 3.4) [9]. The period between 1965 and 2005 has seen a near doubling of the global population (Figure 3.5), placing a much greater demand on agriculture for food [10]. The per capita land area used for cereal crop production has shown a 50% decline during the last half century (Figure 3.6). Increases in oilseed and sugar crop cultivation have only been sufficient to maintain per capita area since 1965. However, major increases in yield mean that the per capita production of all three crop types has shown a modest increase during this period (Figure 3.7). Therefore, overall global agricultural output, and so the general availability of food per person, has increased during the last 50 years [9, 10]. The direct demand for food is not, however, the sole determinant of global agricultural output. Economic factors influence crop production and distribution on global, national, and regional scales. The market demand for vegetable oil has
3.3 Agricultural Production 7
Population (billion)
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Figure 3.5 Global population [10].
0.25
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Figure 3.6 Per capita area harvested of major crop types [9, 10].
led to a major expansion of oilseed rape production in Europe during the last 40 years. More recently, demand for inexpensive carbohydrates and oils has driven the adoption of genetically modified (GM) maize and soybean in both North and South America. In addition, the perceived benefits of organic cultivation techniques have led to a significant consumer demand for higher value, lower yield organic produce in developed nations in recent years. It is clear, therefore, that the consumer has an important role to play in determining the economic viability of agricultural products. However, the price-driven economics of supply and demand are rarely allowed to operate completely independently in the agricultural sector. Market interventions are commonly employed by governments to encourage competition, protect domestic businesses, prevent overproduction, or improve
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3 World Agricultural Capacity 400 350
Production (kilograms per capita)
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Figure 3.7 Per capita crop production for major crop types [9, 10].
environmental sustainability. An important example is the European Common Agricultural Policy (CAP), which determines the subsidies paid to farmers across the European Union. During the late 1980s, the CAP was amended to introduce a system of set-aside, which required farmers to leave a particular proportion of their land uncultivated. It was intended that set-aside would prevent surplus grain production and also provide some environmental benefits. Production was indeed restricted and grain surpluses were depleted during the following 20 years. The set-aside requirement was removed in 2008, although the effect on production is not yet apparent. Systems of subsidies for domestic production and tariffs on imported agricultural goods are common throughout the world. Consequently, there is enormous variation in the price of farmed goods throughout the world and the economic forces affecting production are complex and difficult to predict. 3.3.2 Increasing Production
World agricultural production increased significantly during the second half of the 20th century, more than keeping pace with a rapidly growing human population. This was achieved without a major expansion of the area devoted to crop cultivation. This section will examine the methods used to increase production during this period and discuss how production might be increased still further in future in order to meet the growing demand for food and the new requirements for sustainable energy sources and renewable raw materials. Conventional plant breeding has traditionally been an important way of maximizing arable production. Selective breeding enabled the domestication of crop plants during the early stages of agriculture around 10 000 years ago. During the Green Revolution of the mid-20th century, plant breeding radically altered the most widely used cereal plant cultivars. Major selective breeding programs resulted in higher allocation of carbon to seeds, more efficient use of artificial fertilizers,
3.3 Agricultural Production
and short stature plants better suited to mechanization. Reduced investment by government and industry during the second half of the 20th century has slowed the progress of conventional breeding research. It is unclear whether further artificial selection could lead to still greater increase in yield. However, it is important to note that previous programs have focused entirely on food production. Conventional breeding could also be used to produce varieties better adapted to nonfood production. For example, the fatty acid erucic acid is present in many oil-bearing plants and has many nonfood uses in emulsions, emollients, and surfactants, but is undesirable in food due to its bitter taste. High erucic acid rapeseed varieties have been developed for exclusively industrial purposes. Conventional breeding is less well-suited to perennial crops due to the long time periods required for selection over multiple generations, but may still yield longterm benefits. Application of artificial fertilizers has also led to major increases in crop yield. Since 1965, nitrogen fertilizer use has seen a 6.87-fold increase and phosphorus a 3.48-fold increase [11]. However, these increases are not without significant environmental impacts. More than half of all the fixation of atmospheric nitrogen in world is the direct result of fertilizer production for agriculture [12]. The production of inorganic nitrogen fertilizers results in release of the greenhouse gas nitrous oxide both directly and through nitrification and denitrification in fertilized soils. Application to farmland can also lead to increased nitrogen content of freshwater, potentially causing harmful eutrophication. Anthropogenic nitrogen fixation also represents a major energy demand, often the largest single energy requirement associated with agricultural production. Better matching of fertilization to plant requirements is necessary to minimize these impacts in intensive arable systems. However, fertilization can still increase yield in developing economies where the cost of inorganic fertilizer prevents its widespread use. Water availability is an important determinant of crop production. Irrigation has been used extensively throughout human history to improve agricultural output and to allow production in less favorable conditions. Freshwater is a finite resource and accounts for only 3% of the planet’s water. Humans currently appropriate 54% of total runoff, around 70% of which is used for agriculture [12, 13]. Any further increase in irrigation will likely incur environmental impacts as less water is available for natural ecosystems and more water becomes contaminated with fertilizers, pesticides, and other agricultural waste. Use of ancient aquifers to supplement freshwater supplies is unsustainable. Furthermore, long-term irrigation can lead to progressive salt deposition, making soils unsuitable for cultivation. Soil salinity currently restricts plant growth on more than 351 million hectares of agricultural land worldwide [14]. Pesticides provide crop protection and enable higher yields to be achieved. Chemical pesticide use has risen during the 20th century, although concerns over the effects of compounds on human health and the environment have led to changes in the types of pesticides applied. Consequently, there has been a reduction in the frequency of applications and a move away from broad-spectrum compounds prone to bioaccumulation and wider ecological toxicity. Extensive use
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of pesticides on common monoculture crops can lead to the emergence of resistant pests and pathogens. These factors have led to growing interest in alternative methods of controlling pest organisms, including biotechnology, biological control using natural predator organisms, and using combinations of plants to repel and divert pests. The latter “push–pull” strategy has been used successfully in Kenya, where maize crops have been grown together with desmodium, which repels the maize stem borer, and surrounded with Napier grass, which attracts the insect pest away from the crop [15]. The final traditional method for increasing agricultural production is to expand the area under cultivation. During the 20th century, crop production has increased dramatically with only minor increases in the global arable area, but there is still scope for some expansion. Agriculture currently accounts for 50% of the vegetated surface of the planet [16]. However, it is difficult to quantify the remaining area available for cultivation. Much of the remaining land is either unsuitable or inaccessible. Furthermore, bringing more land under cultivation would inevitably lead to other, likely undesirable, impacts. Destruction of forest will lead to the loss of key biomass and soil carbon stocks, and the use of any land will inevitably result in fundamental changes to biodiversity. Additional indirect, unquantifiable, and unpredictable consequences are also possible. For example, loss of vegetation affects ecosystem water dynamics, potentially leading to flooding or drought both near to and far from the new agricultural land. This has been the case in the Amazon basin, where deforestation, and the consequent loss of deep root systems, has reduced water uptake and resulted in rapid transfer of runoff to streams and rivers, increasing flood risks downstream. Therefore, although an expansion of farmland is possible, it is likely to be associated with immediate and long-term environmental, social, and economic impacts. The late-20th century has seen the development of another technique for enhancing agricultural production. Use of biotechnology has allowed the development of GM crops with novel traits that would be difficult or impossible to achieve using conventional plant breeding. The most established varieties include genes conferring resistance to insect pests or providing tolerance to broad-spectrum herbicides to allow more effective weed control. Although these have not yet led to dramatic increases in yield, they have the potential to reduce the environmental impact and energy requirement of cultivation. Further research could lead to greater fertilizer- or water-use efficiency, or even more direct increases in yield. However, simply lowering the financial cost, labor requirement, and environmental burden of crop management could help maximize production in developing nations where existing techniques and resource availability lead to suboptimal yields. Biotechnology could also provide crop varieties better suited to nonfood raw material production. For example, ethanol yield during fermentation of woody biomass is affected by lignin content. Use of GM tree varieties with low lignin contents could increase lignocellulosic ethanol yield by 20% [17]. A further potential benefit of GM technology is the ability to produce large quantities of enzymes for industrial purposes. Development of modified maize plants that express
3.3 Agricultural Production
enzymes required for starch decomposition allows the inexpensive production of catalysts necessary for the fermentation of carbohydrates [17]. These techniques are in the early stages of development and require extensive environmental impact assessment on a case-by-case basis. However, GM technology has the potential to maximize production of existing crop types and to improve the efficiency of raw material extraction and use on a global scale. 3.3.3 Increasing Availability
In addition to direct increases in yield and production, the availability of agricultural products can be increased by making more efficient use of the existing arable land area. At present, 34% of arable land is used to provide feed for livestock for both meat and dairy production. This accounts for 37% of global arable production [18]. The efficiency with which animal feed is converted to meat means much of the energy and biomass of the cereal is lost either through respiration or by accumulating in inedible parts of the animal. In the case of cattle, 10 kg of cereal are required to produce just 1 kg of beef [18]. The additional production steps also lead to further direct demands on land and energy. A switch to more “efficient” livestock would reduce the demand on land for feed production. For example, 2.4 and 1.7 kg of cereal are needed to produce 1 kg of pork and chicken, respectively. Reducing overall meat consumption would also reduce the demand on land for both feed production and grazing. Some of this land would need to be used to produce food, but the majority would be available for other purposes, including industrial crop production. The removal of livestock would also reduce the environmental impact of agriculture by reducing energy requirements and methane release through enteric fermentation in ruminants. However, meat consumption is linked with prosperity and per capita meat consumption continues to increase, particularly in developing nations. Therefore, any reduction in global livestock farming would necessitate a significant change in attitudes toward food. 3.3.4 Future Prospects
The last 50 years has seen enormous increases in agricultural production, more than meeting the requirements of a growing human population. A combination of traditional techniques and biotechnology is expected to lead to further growth in yield and total production during the next 50 years. However, humans already use between 24% and 40% of global terrestrial net primary production [19–21] and any increase in this share will inevitably come at the cost of further environmental degradation. Population growth is difficult to predict, and problems of distribution and rising incomes in developing economies make it near impossible to assess the future need for food. Furthermore, the complete reliance of agriculture on seasonal climatic conditions and its vulnerability to extreme weather events make it extremely difficult to make accurate predictions of future levels of production.
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Therefore, it is unclear what, if any, surplus agricultural production will be available for use as a source of renewable raw materials. Market demand for high-value products may stimulate increases in production, but the degree to which this is possible remains to be seen.
3.4 Supplying the Chemical Industry
Various sources have suggested that 10% of oil is used in the petrochemical industry [2, 3]. Readily available data show that in the UK, 6% of total oil consumption is accounted for by nonenergy uses [1]. Taking this lower figure as a conservative estimate of global allocation of oil to the chemical industry, this places worldwide petrochemical oil consumption in the region of 220 million tonnes per year. If it is assumed that vegetable oil is functionally equivalent to the petroleum used in the manufacture of chemical products; this means that total global vegetable oil production would meet just 60% of the chemical industry’s oil requirement (Figure 3.8). As mentioned above, such direct substitution would be impractical and potentially undesirable on technical grounds. However, this example highlights the sheer size of the chemical industry and its demand for raw materials. Even using a more diverse range of crops, it is clear that existing scales of chemical production cannot be maintained using agricultural products alone. So how can sustainable production be achieved? 1)
Increase agricultural production to a level sufficient to meet the requirements of the chemical industry without compromising food production.
2)
Reduce the demand for chemical products and maximize recycling so that raw material demands can be met by agriculture with a smaller impact on food production.
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Oil (million tonnes)
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Figure 3.8 Global petrochemical oil use, assuming 6% allocation of total oil production to petrochemicals [1, 4], and total global vegetable oil production [9].
3.5 Summary
3) Find alternative sources of renewable raw materials, such as the production of hydrocarbons from abundant inorganic compounds using renewable sources of energy. A truly sustainable chemical industry will probably rely on a combination of these three approaches. This chapter has shown that there is still scope for increases in agricultural output, particularly in developing economies, and that some materials derived from biomass may have advantages over their petrochemical counterparts. Development of technologies to make use of lignin and cellulose will also increase the amount of biomass available to the chemical industry while reducing pressure on agricultural land. Reducing the demand for chemical products will also make it easier to meet the demand for raw materials in a sustainable way. Current initiatives to reduce the use of plastic carrier bags and to minimize the amount of plastic packaging show how the demand for disposable products can be reduced. The growing demand for food, energy, and chemical products means that agricultural output is unlikely to be sufficient to meet the needs of the entire chemical industry in the foreseeable future. However, agricultural production may be sufficient to supply particular sectors of the market that are currently dominated by petrochemical products. At present, 30.7 million tonnes of polyester fiber is used in the manufacture of clothing textiles [22]. Complete substitution with renewable PLA would require 76.8 million tonnes of cereals [23], which represents only 3% of global cereal crop production. Therefore, although total replacement of petroleum as the primary raw material for the chemical industry is unlikely, agricultural output may be sufficient to meet the demands of certain key industrial sectors. Where agricultural products are insufficiently abundant or lack the required technical properties, other sources of renewable raw materials must be found. For example, green and food waste could provide further sources of organic material for the chemical industry. Therefore, agricultural products are likely to find some more specialist applications within particular market sectors.
3.5 Summary
Petroleum has been the primary feedstock for the chemical industry throughout the 20th century. Recent concerns over the political and economic implications of fossil resource depletion and the environmental impact of fossil fuel use have led to growing interest in agriculture as a source of renewable raw materials. Although biomass has an established role in some specialist applications, wider industrial use of biological compounds will require large amounts of generic building blocks, including starch, sugars, and oils. Production of these substances has increased significantly over the last 50 years, but this has been necessary to feed a rapidly growing global population. Further significant increases will be needed to provide a surplus large enough to supply the chemical industry without affecting food production. A combination of traditional methods and biotechnology are likely to be employed to increase output and better adapt existing crop varieties to meet
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industrial requirements. These measures will come with environmental costs that must be weighed against the environmental and social benefits of using renewable and carbon-neutral materials. The enormous size of the chemical industry and the demand for food from agriculture mean that it is unlikely that agricultural products will completely replace petrochemical materials. However, renewable raw materials may find widespread use in certain market sectors where they confer technical advantages or add value to consumer products. Consequently, agriculture will be one of many contributors to sustainable chemical production.
References 1 DECC (2009) Digest of United Kingdom Energy Statistics 2009. 2 Christensen, C.H., Rass-Hansen, J., Marsden, C.C., Taarning, E., and Egeblad, K. (2008) The renewable chemicals industry. ChemSusChem, 1, 283–289. 3 Dodds, D.R. and Gross, R.A. (2007) Chemicals from biomass. Science, 318, 1250–1251. 4 EIA (2009) World crude oil production 1960–2008. http://www.eia.doe.gov/aer/ txt/ptb1105.html (accessed 11 November 2009). 5 Werpy, T. and Petersen, G. (2004) Top Value Added Chemicals From Biomass, Volume I: Results of Screening for Potential Candidates from Sugars and Synthesis Gas, US Department of Energy, Washington, DC. 6 Turley, D.B. (2008) The chemical value of biomass, in Introduction to Chemicals from Biomass (eds J.H. Clark and F.E.I. Deswarte), John Wiley & Sons, Ltd, Chichester, UK, pp. 21–46. 7 Patel, M., Crank, M., Dornburg, V., et al. (2006) Medium and long-term opportunities and risks of the biotechnological production of bulk chemicals from renewable resources: the potential of white biotechnology. The BREW Project. Utrecht University. 8 Holladay, J.E., White, J.F., Bozell, J.J., and Johnson, D. (2007) Top value-added chemicals from biomass, volume II: results of screening for potential candidates from biorefinery lignin, US Department of Energy. 9 FAO (2009) FAOSTAT. http://faostat.fao. org/ (accessed 11 November 2009).
10 UN (2009) World Population Prospects: The 2008 Revision Population Database. http://esa.un.org/unpp/ (accessed 11 November 2009). 11 Tilman, D. (1999) Global environmental impacts of agricultural expansion: the need for sustainable and efficient practices. Proc. Natl. Acad. Sci. USA, 96, 5995–6000. 12 Vitousek, P.M., Mooney, H.A., Lubchenco, J., and Melillo, J.M. (1997) Human domination of earth’s ecosystems. Science, 277, 494–499. 13 Postel, S.L., Daily, G.C., and Ehrlich, P.R. (1996) Human appropriation of renewable fresh water. Science, 271, 785–788. 14 Rengasamy, P. (2006) World salinization with emphasis on Australia. J. Exp. Bot., 57, 1017–1023. 15 Hassanali, A., Herren, H., Khan, Z.R., Pickett, J.A., and Woodcock, C.M. (2008) Integrated pest management: the push–pull approach for controlling insect pests and weeds of cereals, and its potential for other agricultural systems including animal husbandry. Philos. Trans. R. Soc. Lond., B, Biol. Sci., 363, 611–621. 16 Foley, J.A., DeFries, R., Asner, G.P., et al. (2005) Global consequences of land use. Science, 309, 570–574. 17 Turley, D.B. (2008) Technology and policy requirements in the drive towards improving bioenergy efficiency. Asp. Appl. Biol., 90, 3–10. 18 Garnett, T. (2009) Livestock-related greenhouse gas emissions: impacts and options fro policy makers. Environ. Sci. Policy, 12, 491–503.
References 19 Haberl, H., Erb, K.-H., and Krausmann, F. (2008) Global human appropriation of net primary production (HANPP). http:// www.eoearth.org/article/Global_human_ appropriation_of_net_primary_ production_%28HANPP%29 (accessed 11 November 2009). 20 Vitousek, P.M., Ehrlich, P.R., Ehrlich, A.H., and Matson, P.A. (1986) Human appropriation of the products of photosynthesis. Bioscience, 36, 368–373.
21 David, H.W. (1990) Human impacts on energy flow through natural ecosystems, and implications for species endangerment. Ambio, 19, 189–194. 22 Oerlikon (2008) The Fibre Year 2008/09: A World Survey on Textile and Nonwovens Industry, Oerlikon, Switzerland 23 Lavoisier, P. (2006) Comparison Chart for Biodegradable Materials. http:// www.ideas-int.com/document/avantagessupereco.pdf (accessed 11 November 2009).
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4 Logistics of Renewable Raw Materials Magnus Fröhling, Jörg Schweinle, Jörn-Christian Meyer, and Frank Schultmann
4.1 Introduction
The efforts to use renewable raw materials for energetic and material purposes increase. The intention of this enforced use of renewable raw materials is to replace limited and depleting fossil raw materials such as fossil crude oil, coal, and lignite in power plants, as basis for fuels and chemical building blocks. Thus, the dependency on the fossil resources and contributions to the impacts on the anthropogenic greenhouse effect shall be reduced as well as the raw material and energy basis shall be enforced. Also contributions for strengthening of the agricultural and forest industry may be achieved. In comparison to their fossil counterparts process chains based on renewable raw materials differ in many aspects. Operations for cultivation, harvesting, and provision of renewable raw materials take place in a natural environment. The raw materials accrue spatially distributed on large areas. Amount and characteristics of the resources underlie seasonal variances and restrictions. As a rule, the abilities and capabilities for storage are limited. Long-distance transports are disadvantageous because of comparable high water contents and low calorific values. Because of an increasing usage of renewable raw materials for heat and power generation in energy conversion processes and the development of bio-based synthetic fuels and biorefineries different valorization routes for renewable raw materials compete. This competition is about the limited available and suitable renewable raw materials and in consequence about the land on which it is cultivatable. This has an influence on available quantities, qualities, and the according prices. As the products of renewable raw material-based production chains have to compete with their quantity and quality on markets, besides the technical efficiency of the conversion process valorization routes demand for the development of suitable and efficient logistical concepts. It is the aim of this chapter to characterize renewable raw materials regarding their determining factors for the development of logistical concepts of industrial scale realizations. Particularities of renewable raw materials in general and in particular for selected types, the necessary cultivation, harvesting, preparation, conditioning, storage, and transport Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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steps are described. On the basis of this the consequences concerning planning of industrial scale value chains based on renewable raw materials will be derived. The considerations focus thereby on wood and selected agricultural products. The structure of this chapter is as follows. First, we characterize renewable raw materials concerning the determining factors for logistics. Thereby we also consider the issues regarding the mobilization of the available biomass. Following this the processing steps for the provision of the biomass are explained before we derive the consequences for the planning of the industrial scale utilization chains. Finally, we summarize our contribution and draw conclusions.
4.2 Determining Factors for the Logistics of Industrial Utilization Chains for Renewable Raw Materials
In comparison to industrial utilization chains for fossil raw materials chains for renewable raw materials are differing manifold. In the following, main determining factors leading to different processing steps and special requirements concerning the logistics of renewable raw material-based industrial value chains are discussed. These comprise the natural environment in which it is operated, the characteristics of the renewable raw materials as well as the involved actors and stakeholders which are crucial for the mobilization of the renewable raw materials. 4.2.1 Operating in a Natural Environment
Unlike fossil raw materials, renewable ones are not a result of geological or biological processes of the past but of the present biosphere. Hence, the yield of renewable raw materials such as agricultural crops and wood does not depend mainly on technological but on natural factors like climate, weather, seasons, topography, soil, size and spatial distribution of agricultural land and forests, and finally the type of biomass itself. All these factors need to be kept in mind when setting up a logistics concept for utilization chains of renewable raw materials. The climate is one of the most important natural factors. It is commonly defined as the weather averaged over a longer period of time and described by temperature, precipitation, wind, humidity, atmospheric pressure, and other variables. It determines the length of the growing season and hence the agricultural crops and tree species that can be cultivated as well as the number of harvests per year. The climate of a certain region is affected by its latitude, altitude, terrain, snow, and ice cover as well as nearby water bodies and their currents. Machinery and management methods have to be adapted to the climate. Especially forest machinery has to be able to operate in extreme cold conditions of the harsh winters of the boreal climate zone.
4.2 Determining Factors for the Logistics of Industrial Utilization Chains
The weather in contrast does not affect the selection of agricultural crops or tree species but very much determines their yield and the time for management and harvesting operations. Cold and wet as well as hot and very dry weather usually leads to smaller yields and after a period with heavy rainfall the soil or grain could be too wet for management and, respectively, harvesting operations. Hence management, harvesting, and logistic concepts need to be flexible enough to deal with changing weather conditions. The latitude mainly affects the number and duration of seasons. While forestry is not that much affected by seasons agriculture largely depends on them. Hence, in agriculture harvesting operations usually have to take place during a couple of weeks. In this short period of time rather large quantities of biomass have to be managed, transported, and stored. The machinery used and the logistic concept has to be designed to handle these large quantities. Harvesting of short rotation coppice is seasonal as well. Usually it is restricted to wintertime. This is mainly for two reasons. First, nutrients that are stored in the leaves are kept on site. Second, quality of the wood chips that are usually produced is much better when leaves are off. In forestry, as mentioned before, modern harvesters and forwarders allow for thinning and felling all around the year. Hence, wood logistic concepts are designed to handle a continuous more just in time wood supply rather than to manage and store seasonal biomass peaks. Topography is another natural factor that affects biomass yield as well as management and harvesting operations. The yield of agricultural crops as well as forests varies to a large extent with the exposition and steepness of a slope as well as the altitude. Usually the yield is lower on the upper part of a slope and declines with the altitude. While highly mechanized production of agricultural crops is limited to rather flat terrain, forests are often in hilly and mountainous regions that are not suitable for agriculture. Forest management and harvesting operations in steep terrain require special machinery. Tracked vehicles, for example, can operate in steeper terrain than wheeled ones. If the terrain is even too steep for tracked vehicles, cable cranes and so-called high lines are used to forward logs to the roadside. The type of soil, its chemical and physical properties are as equally important as the climate regarding the selection of crops and their yield. To maintain soil fertility and to prevent soil degradation are key factors for a sustainable yield. Although all management and harvesting operations should be soil-friendly, soil compaction due to heavy machinery and soil erosion due to unadjusted cultivation methods are still a problem in agriculture and forestry. Size and spatial distribution of farm- and forestland do have impacts on the yield of renewable raw materials per area unit and hence on the logistics. If all other factors are equal, the bigger the size of farm- and/or forestland and the higher their share per area unit, the bigger is the harvestable yield. In terms of logistics this means: higher performance and less transfer of machinery, shorter transport distances and finally lower harvesting and transport costs. For a utilization chain based on straw or other low-density and/or low-value feedstock spatial
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distribution of farm- and forestland are important factors with respect to choice of a production site. Management operations, logistic concepts, and machinery have to be adapted not only to the various natural factors mentioned above but also to the different types of renewable raw materials. Cultivation and harvesting of cereals is different from cultivation and harvesting of oil crops, which is different from cultivation and harvesting of maize, which is different from cultivation and harvesting of short rotation coppice and so on. There is no “one-for-all” solution. Hence, a multifeedstock utilization chain requires more complex logistics, which result in higher costs for feedstock supply. 4.2.2 Characterization of Selected Renewable Raw Materials
Besides the determining factors induced by the natural environment as discussed in the previous section, the success of the production of renewable resources in terms of yield, profitability and ecological performance is also determined by the type of renewable raw material. To give an overview of the requirements of the most important factors for the most promising renewable raw materials for Central Europe, we characterize these in the following by describing the requirements for their production, their production amounts, the current geographical distribution of production as well as current and potential industrial usages. We consider oil, sugar, and starch crops, lignocellulosic biomass, biogenic residues, and algae. 4.2.2.1 Oil Crops Fatty oils are esters of glycerin (glycerol), the simplest triol, and fatty acids, carboxylic acids with chain lengths from C4 to C24. The group of plants that produce fatty oils as storage matter is heterogenic. Some of them have been domesticated for a long time in various parts of the world with many subspecies and hybrids used for vegetable oil delivery. Therefore, oil crops are not limited to a single taxonomic family but are found among Asteraceae, Brassicaceae, Fabaceae, or Palmae, for instance. Due to climate- and soil-related cultivation restrictions, different oil crops are characteristic for different parts of the world. Nevertheless, a global market exists and international trade in oil seeds, vegetable oils, and respective by-products is significant. The major oil crops worldwide are oil palm, soybean, rapeseed (canola), and sunflower (see Table 4.1). The latter three are described in more detail below. Palm oil, which is obtained from the oil palm tree mainly planted in South East Asia (especially in Indonesia and Malaysia), grew to be the vegetable oil with the highest consumption (42.1 million tons, 30%) ahead of soybean oil (37.9 million tons, 28%) [1]. It has several applications in food, oleochemicals, and other industries [2], while it is also discussed as a major source for biodiesel. Soybean Though originally from China, soybeans are the main oil crops in the United States today. The United States and Brazil have the highest shares in global
a) b) c) d) e) f)
Source: [3, 4]. 2008, Source: [1]. Area harvested 2007. Source: [5]. Average yields 2007. Source: [5]. Oil content of pulp, fresh weight basis. Oil content of copra.
Indonesia USA China Russia China India Philippines
13 854 726 90 199 626 30 805 326 21 491 683 33 057 930 23 105 413 11 106 109
50 14–24 40–50 50–60 15–22 42–52 65–70
Oil palme) Soybean Rapeseed Sunflower Cotton Groundnut Coconut palmf) 42.1 37.9 19.9 10.3 5.0 4.5 3.2
Seed oil contenta) Oil consumptionb) Leading growerc) Acreage (% dry matter) (million t a−1) (acreage based) worldc) (ha)
Crop
Table 4.1 Overview characteristics and production statistics of selected oil plants.
– 1 000 1 548 177 19 161 – – –
– 349 464 6 487 988 3 277 494 364 448 10 625 –
13.90 2.45 1.64 1.25 2.23 1.61 5.54
Acreage EUc) Acreage Germanyc) Yield worldwided) (ha) (ha) (t ha−1 a−1)
– 1.00 3.44 2.65 – – –
Yield Germanyd) (t ha−1 a−1)
4.2 Determining Factors for the Logistics of Industrial Utilization Chains 53
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production [3]. In Germany, soybeans contributed the largest share to oilseed imports with 3.5 million tons out of 6.8 million tons in 2008. Compared to the world’s largest producers, the acreage planted with soybean in the European Union (EU) is marginal. According to FAO statistics [5], 349 464 ha were harvested in the EU in 2007, a mere 0.4% of the more than 90 million ha harvested worldwide. The FAO estimates the world average yield to have been 2.45 tons per hectare in 2007. In the United States and Brazil average yields above 2.80 tons per hectare were achieved in the same year. In Italy, the EU’s largest soybean producer, the respective value was 3.33 tons per hectare, while for the 1000 ha harvested in Germany in 2007, only one ton per hectare is registered. This shows the unsuitable growing conditions for soybeans in Central Europe and explains the high level of imports into that region. Soybean (Glycine max), a legume from the Fabaceae family, is an annual, diploid crop that reaches a height of 75 cm maximum. It develops up to 20 small white or purple flowers and short, hairy pods with normally three to four mostly yellow seeds. Self-pollination is the rule [3]. Soybeans are planted for oil and protein delivery. Depending on the cultivars the oil content varies between 14 and 24%, while the protein content shows a variation of 30–50% [3] of dry matter. The oil is rich in linoleic acid (49–57% of fatty acids) and suitable for edible purposes. The 6–11% linolenic acid content causes problems concerning oxidation and undesired flavor. Hydrogenation of soybean oil and development of low-linolenic cultivars are current measures to overcome them. The third fatty acid contributing a significant share to soybean oil composition is oleic acid, varying approximately between 18 and 25% [2]. The main by-product resulting from soybean processing is soybean meal, left after oil extraction. Due to its high protein content of 42–47% (12.5% moisture [6]) including all amino acids essential for nutrition, it is a valuable animal feed. The worldwide consumption of soybean oil was 37.9 million tons in 2008, accounting for 28% of global vegetable oil usage [1]. It finds its way into several food applications such as cooking oils, salad oils, or margarines. Technical uses include additives for coatings. In the biofuels industries of the United States and Brazil, soybean oil is also the main feedstock for biodiesel production (almost 20% of soybean oil went into biodiesel in the United States in 2008 [7]). Future contracts for soybean and soybean meal are traded at the Chicago Board of Trade and can be considered as lead prices for oilseed and oilseed meal world markets [8]. As with other agricultural commodities, prices are generally very volatile. Quotations assembled by the FAO can give an indication of recent ranges. The annual average price for soybean seed originating from the United States traded in Europe (No. 2 yellow, CIF1) Rotterdam) was 275 US$ per ton in 2005, peaked at 523 US$ per ton in 2008, and came down again to 435 US$ per ton in 2009. Soybean meal from Argentina shipped to the European market (Pellets, 44/45% protein, CIF Rotterdam) was traded at 214 US$ per ton on average in 1) CIF: Cost, Insurance, Freight.
4.2 Determining Factors for the Logistics of Industrial Utilization Chains
2005, at 423 US$ per ton in 2008 and was still on a high level with 410 US$ per ton as the yearly average price in 2009 [9]. Rapeseed (Canola) Rapeseed is the most widespread oil crop in Europe, as it can be grown under cooler and more temperate climate conditions than oil palms or soybeans. It is today the third most-consumed vegetable oil with 19.9 million tons in 2008 [1]. With more than 20% of the rapeseed acreage harvested worldwide the world’s leading rapeseed growers are China and India. In the European Union, altogether about 6.5 million hectares of rapeseed were harvested in 2007, equaling 21% of world rapeseed acreage. France and Germany were the most important EU growers in 2007, with 1.58 million hectares and 1.55 million hectares, respectively. Yields vary significantly between the countries mentioned above. Whereas in Germany, an average of 3.44 tons per hectare could be reached in 2007, the respective figure was 2.89 tons per hectare in France, 1.47 tons per hectare in China, and only 1.10 tons per hectare in India. This explains the relatively low average yield of 1.64 tons per hectare worldwide [5]. Different species of the Brassicaceae family are actually grown as rapeseed crops. Brassica napus dominates in Europe. It is a mainly self-pollinated, about one-third out-crossing amphidiploid most likely originating from hybridization of wild diploid Brassicae. Spring-sown varieties are used in Canada, while winter-sown cultivars are chosen in most European countries [2]. The plant reaches a height of 120–200 cm and develops yellow flowers and 5–10-cm long pods containing 15–20 seeds [10]. The seeds contain 40–50% oil and 20–25% protein (dry matter basis [3]). Originally, the fatty acid with the highest share was erucic acid with 25–50% in the seed oil. Due to the negative nutritional effects attributed to erucic acid in Western countries, and because of glucosinolate contents, the composition of rapeseeds prevented the use of the oil for food and the use of the meal for fodder. At first, low erucic acid (less than 5%, meanwhile less than 2.5%) cultivars were developed. Later, one was also successful in breeding low glucosinolate varieties, finally yielding so-called double-zero cultivars now almost exclusively sown. In Canada, this rapeseed especially suited for edible purposes is referred to as canola [3]. As erucic acid has been primarily replaced by oleic acid, the fatty acid fraction of low-erucic acid rapeseed oil is composed of 52–66% oleic acid, 17–25% linoleic acid, and 8–11% linolenic acid. The reduction of the glucosinolate content enables to use the meal obtained during oil processing as protein rich (33%, 11.5% moisture basis [6]) animal feed. Nevertheless, rapeseeds are currently grown to deliver oil in the first place. Margarine, frying oil, and salad dressings are examples of rapeseed food products. Another important application has emerged in the growing biofuels sector, with rapeseed methyl ester (RME) being the primary biodiesel in Europe, above all in Germany. High erucic acid rapeseed oil is still used in industrial processing, delivering biodegradable oils, lubricants, surfactants, and other oleochemicals [2].
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The annual average price for double-zero rapeseed from Europe (CIF Hamburg) was 260 US$ per ton in 2005, climbed to 605 US$ per ton in 2008, and reached an average of 389 US$ per ton for the year 2009. Prices for rapeseed meal are lower than for soybean meal because of the lower protein content. The average price for European rapeseed meal with a protein content of 34% (Hamburg, FOB2) ex-mill) was 204 US$ per ton in 2009 [9]. Sunflower The sunflower originates from dry western parts of what is today the United States. It was brought to Europe in the 16th century and is now planted in Asia, South America, Africa, and Australia as well. Sunflower oil ranked as the number four vegetable oil in 2008, with a global consumption of 10.3 million tons or a share of 8% [1]. In 2007, about 21.5 million hectares of sunflower were harvested worldwide. The leading grower was Russia with more than 5 million hectares, followed by Ukraine with 3.4 million hectares. That was still more than the whole EU acreage cultivated with sunflower in 2007. Germany is only a minor producer, with 19 000 ha harvested, albeit with a high average yield of 2.65 tons per hectare in that year. World average yield was 1.25 tons per hectare which is about the value achieved in Russia and Ukraine, whereas Romania, the most important EU sunflower grower in terms of acreage, registered an average yield of only 0.73 tons per hectare. The botanical name of sunflower is Helianthus annuus, a predominantly crosspollinated [3] species of the Asteraceae family. Sunflowers are annual crops with a height of up to 300 cm and a distinguishing, 15–30-cm diameter head. This inflorescence is composed of yellow flowers forming an outer ring and a brown inner circle of florets (250–1200 per head) which develop the sunflower fruits containing the hulled seeds. The seeds have an oil content of about 50%, which could be reached through years of breeding efforts [3]. The fatty acids of the oil fraction consist of 55–73% linoleic acid and 14–34% oleic acid as main fatty acid components [2]. Variation in fatty acid composition is dependent on the cultivars and furthermore influenced by temperatures during cultivation. The by-product obtained from oil milling is a defatted meal with 40–45% protein, making it suitable for both food and feed applications. Sunflower is primarily grown for edible oil delivery with typical vegetable oil uses in food products. Nonfood uses include manufacturing of paints and coatings, plasticizers, lubricants, and oleochemicals. Special high oleic acid cultivars were bred for industrial applications [10]. European sunflower seeds (CIF, Lower Rhine) were traded at 303 US$ per ton in 2005. In 2008, this value had more than doubled to 656 US$ per ton, whereas in 2009, an average level of 373 US$ was reached [9]. Other Oil Crops Another vegetable oil of global importance is cottonseed oil, with significant production in the United States and China, for instance. It is rich in 2) FOB: Free On Board.
4.2 Determining Factors for the Logistics of Industrial Utilization Chains
linolenic, palmitic, and oleic acid and is used as salad oil. Coconut oil is obtained from the coconut palm grown in the tropics and contains mainly saturated fatty acids. Whereas nutritional uses of coconut oil dominate, the cosmetics industry uses a certain amount for soap production [2]. Besides these oil crops mainly used either directly or indirectly as food, some oil-bearing plants are discussed especially for industrial applications. Crambe (Crambe abyssinica) belongs to the Brassicaceae and is of interest because of its high erucic acid content, which makes up to about 60% of the 50–55% of oils contained in the seeds [10]. Possible applications could be the processing of lubricants, plasticizers, or epoxy resins. Safflower (Carthamus tinctorius) is, like sunflowers, a plant of the Asteraceae and was hitherto grown in smaller amount to provide natural dye or nutritional oil. Safflower cultivation can be found mainly in India, Mexico, the United States, and Argentina, with no significant production in Europe. The global area harvested was 735 918 ha in 2007 with an average yield of 0.85 tons per hectare. This low yield was surpassed on the 69 605 ha in the United States with 1.36 tons per hectare on average in 2007 [5]. The oil in the seeds (27–34%) is composed of 73–79% linoleic acid and 11–17% oleic acid [11]. The possibility to grow safflower on relatively dry and sandy soils may increase its importance as an industrial crop in the future. Linseed or flax (Linum usitatissimum) is another example for an oil crop that has a fatty acid content suitable for uses apart from the food sector, for example in the coatings, paper, detergent, and plastics industry. More than 2 million hectares were harvested in 2007, for the most part in Canada (with an average yield of 1.2 tons per hectare), China, and India [5]. 4.2.2.2 Sugar Crops Sugar crops deliver mainly two types of sugar which can be used for industrial purposes – sucrose, a disaccharide composed by one glucose and one fructose monomer, and inulin, a polysaccharid. The latter can be obtained from topinambur (Helianthus tuberosus) but is only of minor commercial importance. One example for such an application is the production of diets for diabetics [10]. The main species to deliver sucrose are sugarcane and sugar beet. Cane sugar and beet sugar are both sucrose sugars and differ only marginally in the content of carbon isomers and of nonsugar substances. Nevertheless it is possible to determine the origin of a sugar [12]. Sucrose sugars are generally used in food and beverages as universal sweetener, either directly by consumers or via industrial food processing. A beet root subspecies is also planted as animal feed. Ethanol in Brazil is made from sugarcane and some European countries, the United Kingdom, and Germany for instance, have recently started to use sugar beet as feedstock for bioethanol production. Sugars can be used in chemical and fermentative processes for numerous applications as an intermediate as well as fine or specialty chemical [12]. A by-product that accrues in both cane and beet sugar production is molasses, a syrup containing about 50% sugars. While about 47.5 kg of molasses are obtained from the processing of 1 ton of sugarcane, 32.5 kg of molasses are left from the processing of 1 ton of sugar beet. This by-product is used as animal feed as well
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as fermentation feedstock in industry. If molasses is fermented, vinasse remains. Depending on the production process, the resulting substance contains protein and mineral nutrients stemming from cane or beet cultivation and therefore provides another animal feed, primarily used for cattle and sheep [13]. Table 4.2 gives an overview on the characteristics and production statistics of sugarcane and sugar beet. On the world market, the benchmark future contract for both cane and beet raw sugar is called “Sugar No.11,” traded at the Intercontinental Exchange (ICE) in New York. Its average price between 06/2007 and 08/2009 is estimated to have been 278 US$ per ton by the OECD and the FAO [14]. Sugarcane Sugarcane cultivation is believed to originate from New Guinea [12] and as the crop requires warm climate with adequate rainfalls, its production is concentrated in tropical and subtropical countries. Brazil and India possess by far the largest areas dedicated to cane plantation, with about 31 and 21% of sugarcane area harvested worldwide in 2007 (7.1 million hectares and 4.9 million hectares). These countries realized average yields of more than 70 tons per hectare that year, values that could not be met by the EU’s largest grower, Spain (57 tons per hectare on a total of 300 ha). The only other European country with sugarcane cultivation is Portugal with a harvested area of 60 ha in 2007 [5]. Saccharum officinarum, the sugarcane crop, is a hybrid from several Saccharum species. Through continuous breeding efforts, high yields and sugar contents could be reached. The stalks processed in sugar mills contain 73–76% water and 24–27% solids, of which 10–16% are soluble solids. These soluble solids in the sugar juice obtained from crushing are 70–88% sucrose, 2–4% glucose, and 2–4% fructose. The main by-product formed during processing is sugarcane bagasse, a lignocellulosic biomass consisting of 40–60% cellulose, 20–30% hemicelluloses, and 20% lignin (dry matter [15]). It is usually used energetically but not all bagasse is needed to fulfill the energy demands of the sugar mills [12], allowing to sell the steam and power surpluses. Nonenergy applications of bagasse include pulp production [16, 17] and recently, ethanol fermentation. Sugar Beet In the 18th century it was discovered in Prussia that certain beet roots contain sugar. It was only in the 19th century that subsequently sugar production from beet commenced in Europe, thereby providing a domestic alternative for cane sugar imports. In 2007, sugar beets were harvested from 5.2 million hectares worldwide. To that area, the EU contributed more than one-third with 1 816 741 ha. The leading sugar beet growing country in 2007 was Russia with 991 970 ha, followed by Ukraine with 577 000 ha, Germany with 402 697, and France with 393 500 ha. Average yields were highest in Western Europe, where 84.4 tons per hectare in France and 62.4 tons per hectare in Germany could be achieved [5]. The species known as sugar beet is a subspecies of Beta vulgaris of the Amaranthaceae family. It is a biennial, hybrid crop domesticated from wild beets to obtain high sugar content that are stored in the root.
1 743 092 995 227 585 414
Productionb) (t a−1)
Source: [15]. 2008. Source: [5]. Area harvested 2007. Source: [5]. Average yields 2007. Source: [5].
12–17 17–18
Sugarcane Sugar beet
a) b) c) d)
Sugar contenta) (%)
Crop
Brazil Russia
Leading growerc) (acreage based) 22 724 997 5 172 671
Acreage worldc) (ha) 360 1 816 741
Acreage EUc) (ha)
Table 4.2 Overview characteristics and production statistics of sugarcane and sugar beet.
– 402 697
Acreage Germanyc) (ha)
70.0 47.7
Yield worldwided) (t ha−1 a−1)
– 62.4
Yield Germanyd) (t ha−1 a−1)
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The content of glucose and fructose is around 17%, that is, a sugar yield of approximately 9 tons of sugar per hectare and annum is achievable. The water content of sugar beets is between 75 and 78% [12]. With every ton of sugar beet approxlimately 666 kg of beet leafs accrue. These can either be used as animal feed or remain as organic fertilizer on the field [18]. 4.2.2.3 Starch Crops Cereals are the most important crops for human nutrition. Besides, they provide a further possible source for energetic as well as material utilization of renewable raw materials. With starch, they deliver a glucose polymer consisting of amyloseand amylopectin molecules. There are already numerous existing utilization pathways for starch, mainly in the food and feed chains but also for industrial applications. The use of cereals for energetic and industrial purposes is from an ethical point of view often questioned. These problems can be partially avoided through the cultivation of nonedible cereals and the usage of set-aside land, though this is recently no longer required by the Common Agriculture Policy of the EU as a means to reduce production capacity, or areas which are not suitable for food and feed production. The following characterization of starch crops describes maize, potatoes, wheat, and other cereals in more detail. Another significant source for starch is rice. However, cultivation is both technically and traditionally concentrated in Asia, so rice is mainly imported into Europe as food and so far does not play a role as renewable raw material (for rice straw, see Section 4.2.2.4). Table 4.3 gives an overview for selected starch crops in terms of characteristics and production statistics. Maize The cultivation of maize (corn) dates back to the ancient civilizations of Central and South America. It was brought to Europe during the time of the Spanish Empire and is today, besides production in the United States, also grown in Asia, Australia, and Africa. According to FAO statistics, the United States is ranked as the leading grower with more than 35 million hectares harvested in 2007, equaling about 22% of world acreage [5]. This is followed by China, with almost 30 million hectares harvested. Taken together, the EU’s respective area is 8.2 million hectares; a value to which Romania contributed the highest single country share. However, with 1.7 tons per hectare the average yield in Romania was very low compared to those in the United States with 9.5 tons per hectare, or Germany, where about the same average yield could be obtained on a much smaller area (403 200 hectares in 2007). Generally, maize reaches the highest yields of all cereals. Assuming a yield of 7 tons of maize per hectare and year, 4.4 tons of starch and about 9 tons of straw accrue per hectare a year. Maize (Zea mays) is part of the cereals, a group of grasses taxonomically belonging to the Poaceae family. It is an annual crop that can reach a height of 4 m. Corncobs represent the female inflorescences and develop 8–18 rows of 25–50 kernels. The C4 plant has a starch content of about 62% (fresh matter) [15]. Maize is an important source for human nutrition, and is consumed either directly or as processed foods such as tortillas or porridge [19]. Maize starch is
Source: [15]. 2008. Source: [5]. Area harvested 2007. Source: [5]. Average yields 2007. Source: [5]. Dehulled.
73 62 15 58 62 52 70 57
Ricee) Maize Potato Wheat Barleye) Rye Sorghum Oate)
a) b) c) d) e)
Seed starch contenta) (% fresh matter)
Crop
193 354 175 822 712 527 314 140 107 689 945 712 157 644 721 17 750 767 65 534 273 25 784 608
Productionb) (t a−1) India USA China India Russia Russia USA Russia
Leading growerc) (acreage based) 155 998 669 158 034 025 18 531 194 214 207 581 55 441 486 6 307 272 46 928 032 11 597 407
Acreage worldc) (ha)
Table 4.3 Overview characteristics and production statistics of selected starch crops.
419 334 8 284 706 2 240 645 24 794 641 13 679 256 2 567 801 97 835 2 979 817
Acreage EUc) (ha)
403 210 274 961 2 992 075 1 916 871 670 939 – 177 831
–
Acreage Germanyc) (ha) 4.20 5.01 16.7 2.83 2.41 2.34 1.35 2.15
Yield worldwided) (t ha−1 a−1)
9.45 42.4 6.96 5.42 4.02 – 4.09
–
Yield Germanyd) (t ha−1 a−1)
4.2 Determining Factors for the Logistics of Industrial Utilization Chains 61
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mainly required for the production of glucose syrup, a sweetener used in the beverages industry, especially for soft drinks. In the United States, nearly 100% of glucose syrup is produced from maize and 84% in Japan, respectively. Of the 27.6 million tons of maize starch produced per annum in the United States, 70% is used as glucose-based sweetener [19]. A pure industrial application of maize starch can be found for instance in the paper industry, where it is used as adhesive [20]. However, the most important nonfood application of maize is to be found in the energy sector. In the United States the production of ethanol via hydrolysis of the starch and subsequent fermentation of glucose sugars dominates the biofuels business. In 2009, more than 32% of the maize harvest was provided for bioethanol production [21]. In Germany on the other hand, where there is no significant food maize production, the crop is primarily grown to deliver animal feed and to supply biogas plants. Type and amount of by-products depend on the primary usage of maize, which ranges from whole crop usage (animal feed) to kernel usage only (sweet corn food). In the latter case, leaves and stalks and even the corncobs are by-products (see Section 4.2.2.4). A by-product from corn starch processing is protein-rich corn steep liquor, the water resulting from corn steeping. Dried and concentrated, it can be used as animal feed or as nutritional additive in fermentation media [20]. Other processing by-products are gluten feed, a mixture of steep liquor and fiber residues used as cattle feed, gluten meal for poultry nutrition, and maize germ meal [20]. While the average price for the US maize No. 2 contract (Yellow, U.S. Gulf) was at 98 US$ per ton in 2005, it steeply increased and averaged 223 US$ per ton in 2008. The annual average for 2009 was lower, standing at 166 US$ per ton [9]. Potatoes Potatoes have their origin in the Andean region of South America where they were and still are planted as food crops. However, production today is not limited to that region. In 2007 the largest areas were harvested in China (4 436 700 ha, 23.9%), Russia (2 851 660 ha) and the EU (2 240 645 ha). Poland (569 600 ha), and Germany (274 961 ha) were the leading growers within the latter. While yields in China and Russia were below the world average yield of 16.7 tons per hectare, potato growers in Germany obtained a high average yield of 42.3 tons per hectare in 2007 [5]. Solanum tuberosum is a species of the Solanaceae family. The perennial, crosspollinated plant reaches a height of about 80 cm and develops white or purple flowers and a thick characteristic tuber. The tuber has a starch content of about 15% (fresh matter) consisting of 79% amylopectin and 21% amylose [10]. Potatoes have two main uses. The first usage is for food. The tubers are prepared for direct consumption or processed to products like chips or crisps. A further use in the food industry is the supply of thickening agents, binders, stabilizers, and other ingredients. The second is the use as feedstock for industrial starch. Starch derivatives are used in textile and paper products and they are used as adhesives. The overall industrial starch usage in Germany accounts for almost one-third of the German potato production [10]. Industrial potato starch is largely produced
4.2 Determining Factors for the Logistics of Industrial Utilization Chains
from cull, waste, and surplus potatoes and therefore not always directly competing with food potato harvest [20]. About 10% of the potato input for starch processing results in potato pulp. In addition to starch, this pulp contains cellulose, hemicellulose, pectin, and protein. It is used as organic fertilizer, as cattle feed, as substrate for fungi cultivation, or for microbial enzyme production. Further uses are proposed in lactic acid fermentation and adhesives production. The potato fruit liquid by-product is used for protein enrichment and as fertilizer [22, 23]. Since mid-2009, futures on European processing potatoes are traded at the Eurex, a derivatives exchange based at Frankfurt and Zurich. In the first months of trading till the end of the year, prices moved between approximately 100 and 150 EUR per ton [24]. Wheat and Other Cereals Wheat, barley and rye are cereals belonging to the Gramineae family. Wheat is by far the most important crop among them. With 214 207 581 ha harvested globally in 2007, it is the most widely grown crop in the world. In 2007, the largest area planted with wheat was found in India (more than 28 million hectares). Due to a low average yield of 2.7 tons per hectare, India was not the largest producer. With their respective average yields, China (4.6 tons per hectare on 23.7 million hectares) and the EU (24.8 million hectares) produced far more wheat in 2007. A very high yield was achieved in Germany (6.96 tons per hectare), the EU’s second largest grower (2 992 075 ha) after France (6.26 tons per hectare on 5 238 000 ha) [5]. Botanically referred to as Triticum aestivum it is a hexaploid annual crop that has been cultivated for hundreds of years. The grass is self-pollinated and develops 50–80 seeds per spike. The seeds show a high share of starch (58% of fresh matter), which consists of 28% amylase and 72% amylopectin, and the water content is 15% [10]. Wheat is one of the most important food crops in the world but its usage is not limited to nutritional products. Industrial applications are comparable to other starch crops and include adhesives, biomaterials, and ethanol production [10]. Like other commodities, wheat prices saw a hike in 2008. The average price of US wheat No. 2 (Hard Red Winter ord. Prot, US FOB Gulf) was 344.58 US$ per ton. Prices came down since then, to 235.69 US$ per ton as the average for 2009 [14]. Barley (Hordeum vulgare) is the second most widely grown Gramineae with 55 441 486 ha harvested worldwide in 2007, to which the EU contributed 24.7%, followed by Russia with 15.1% [5]. The dehulled kernel fresh matter contains about 62% starch and 10–16% protein [15]. Well-known for its use to produce malt for the brewing of beer, this application is actually surpassed by utilization as animal feed (in the United States 69% [25]). Rye (Secale cereal) is planted mainly in Russia and the central, northern, and eastern parts of Europe, where it can be grown instead of wheat because of its higher tolerance toward lower temperatures. However, the starch content of rye is also lower than that of wheat and the area harvested in 2007 was relatively small with 6 307 272 ha globally. Most of the production is used for bread baking, while
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triticale, a crossing between rye and wheat, is exclusively used as a fodder crop [15] and harvested from about 3.6 million hectares ([5] for 2007). Sorghum is the third most important cereal in the United States and of great importance in Africa and Asia, where more than half of the world production comes from. Besides traditional uses as food and feed, this crop has gained attention because of its relatively good tolerance of dry and hot cultivation conditions. Oats are other important feed crops for cattle and especially for horses, while good health effects are also appreciated increasingly in human nutrition. With applications in paper and adhesives businesses, industrial usage resembles that of other starch crops [25]. The main by-product of cereals is straw, which will be dealt with in Section 4.2.2.4. 4.2.2.4 Lignocellulosic Biomass Wood is by far the most used and versatile lignocellulosic biomass and hence is in the main focus of this section. Other lignocellulosic biomass like grasses and lignocellulosic residues are compared to wood of minor importance but nevertheless shortly described. The main sources of wood are trees of natural and seminatural forests as well as forest plantations. 3.95 billion hectares of forests and forest plantations cover round about 30% of the land surface [26]. The largest forests are situated in Russia, Canada, Brazil, and the United States. Depending on the natural factors forests are either predominated by broadleaved trees or conifers. Broadleaved or hardwood trees belong to the taxonomic class of Angiospermae, while the conifers (Pinales) or softwood trees belong to the class of Gymnospermae. Wood The main compounds of wood are cellulose, hemicellulose, and lignin. Their share varies between hardwood and softwood as well as between single species. Table 4.4 shows the average shares of compounds in the cell wall of European hard- and softwood. Additionally, wood and bark contain a variety of extractives that are of interest for chemical and pharmaceutical applications. Due to the versatile physical and chemical characteristics applications of wood are numerous. However, the main uses for wood are heat and/or power generation
Table 4.4 Average shares of compounds in the cell wall of European hard- and softwood [27].
Compound
Hardwood (%)
Softwood (%)
Cellulose Hemicellulose Lignin Extractive Minerals
42–51 27–40 28–24 1–10 0.2–0.8
42–49 24–30 25–30 2–9
4.2 Determining Factors for the Logistics of Industrial Utilization Chains
as well as a raw material in saw milling, woodworking, pulp and paper as well as wood-based materials industry. On a global scale, the average sustainable yield of forests is about 0.75 dry tons per hectare and year. In contrast, the sustainable yield of forest plantations is remarkably higher and varies between 1.5 and 25 dry tons per hectare and year. In 2006 the global annual production and consumption of roundwood amounted to 3.5 billion m3 [26]. Of this, 53% were used as fuelwood and charcoal, while 47% were used as a raw material in forest industry. The average growth of German forests is according to the second national forest inventory (BWI2) 12.1 m3 per hectare and year. According to Mantau [28] in 2008 roundwood production in Germany amounted to 71.9 million m3 (see Table 4.5). Unlike for most agricultural crops, there is no global market price for roundwood. This is because the price very much depends on the specie, dimension, and quality of a piece of roundwood and the fact that the majority of roundwood is not traded on commodity exchanges. Wood prices are very diverse and even differ regionally. Hence, there are no global or national prices to report. Wood Residues Industrial wood residues are coproducts of the sawmilling industry like shavings, sawdust, and wood chips as well as residues of other parts of forest industry. Sawmilling residues are mainly used as a raw material for board as well as pulp and paper industry. The other residues are mainly used for heat and/or power generation. On a global scale, data on production and consumption of industrial wood residues are not available. According to Mantau [28] in 2008 the amount of industrial wood residues in Germany was 24.1 million m3 (cf. Table 4.5). Those fractions of thinning and felling operations that due to their technical properties (e.g., small diameter, shape, etc.) are not suitable for material use are called forest residues. However, in principle forest residues are still suitable as a
Table 4.5 Wood balance for Germany in the year 2008 [28].
Supply
2008 (in million m3)
2008 (in million m3)
Use
Industrial roundwood Other merchantable wood Forest residues Sawmilling residues Bark Other industrial residues Black liquor Wood waste Landscape management Energy products (pellets) Balance compensation Total
42.8 29.1 6.4 16.5 3.0 7.6 3.5 10.5 4.6 2.8 0.0 126.7
42.5 16.5 10.3 2.7 0.0 2.8 19.8 5.0 25.2 0.1 1.8 126.7
Sawmilling industry Derived timber products Pulp Other wood industry Other industries Energy products (pellets) Energy generation > 1 MW Energy generation < 1 MW Domestic woodfuel Other energy uses Balance compensation Total
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feedstock for utilization chains and of course for heat and/or power generation. On a global scale there are no reliable data on production and consumption of forest residues available. For Germany the wood balance for 2008 by Mantau [28] indicates 6.4 million m3 of wood residues being available. Short Rotation Crops Short rotation crops are an additional source of lignocellulosic biomass. Depending on the country and crop (trees or grasses) short rotation crops are either regarded as a forest, forest plantation, or permanent agricultural crop. The concept of short rotation crops is based on the ability of plants to shoot again after harvest and the dynamic growth of certain plant species. The time period between harvests can vary between 2 and 20 years depending on the production aim. If feedstock for energy generation, liquid biofuel, or chemicals is production aim, a rotation length between 1 and 7 years is optimal. If the feedstock has to have a certain dimension like industrial roundwood for pulp and paper industry, a rotation length between 7 and 20 years is favorable. Among tree species willow (Salix), poplar (Popolus) as well as black locust (Robinia) are the most common in Western and Central Europe. In the subtropics and tropics eucalypti (Eucalyptus ssp) are the most favorable tree species. Depending on water availability and site conditions the yield of willow, poplar, and black locust in Europe can reach 3–20 dry tons per hectare and year [29] while in the subtropics and tropics the yield of eucalypt can reach 30 dry tons and more per hectare and year [30]. Forest plantations are a remarkable source of wood on a global scale. Based on [26] one can estimate their potential wood supply to be some 1.75 billion m3 in 2005. In Western and Central Europe, however, wood supply from short rotation crops is marginal. In Sweden, Hungary, and Poland some 10 000 hectares are stocked with willow and black locust whereas in other European countries short rotation crops are cultivated on a few hundred to thousand hectares. Miscanthus (Miscanthus ssp), switchgrass (Panicum virgatum), and giant reed (Arundo donax) are perennial rhizomatous grasses that can be regarded as short rotation crops. In Europe and on a global scale only a few thousand hectares are cultivated as short rotation crops. Hence, as a source for lignocellulosic biomass perennial grasses are of minor importance. According to Clifton-Brown and Lewandowski [31], annual yields reach 4–44 dry tons per hectare. As a feedstock for heat and/or power generation grasses are due to their comparable high chlorine, sulfur, and potassium contents less favorable than wood. KCl and K2SO4 lead to depositions on heat transfer surfaces as well as corrosion. The release of chlorine and sulfur to the gas phase additionally leads to high emissions of HCl and SO2. But especially as a feedstock for ethanol production the perennial grasses promise higher ethanol yields per hectare compared to corn. Forage grasses (e.g., perennial ryegrass) are either grown on permanent or temporary grasslands. Traditionally used as animal feed, often in the form of hay or silage, they are also a potential raw material for biogas and fine chemicals production [32]. Regarding market prices for short rotation crops, there is the same situation as for wood. There are no global or national prices to report.
4.2 Determining Factors for the Logistics of Industrial Utilization Chains
Straw and Other Crop Residues Crop residues are another source of renewable feedstock that do not find their way into milling processes, especially the residues which are already separated from the crop during or directly after harvesting. For most cereals and oil crops, this lignocellulosic biomass is called straw, for example, wheat straw, rice straw, or barley straw. The crop residues of maize are known as corn stover. A certain amount of straw is usually left on the field to enhance soil recreation or because collection (and pressing of bales) is not profitable. Otherwise, it is used as animal feed or as litter in livestock keeping (horses, cattle). Despite these traditional uses, a remainder of crop residues is generally considered to be available for energy and industrial production. This feedstock potential depends on the amount assumed to have to be left on the field and required for food and feed. In a publication by the government of the German state of Saxony-Anhalt taking into account EU cross-compliance regulations for humus balancing, a share of about 30% has to remain on the fields [33]. Kim and Dale on the other hand base their crop residues potential calculations on a 60% ground cover requirement due to uncertainties. For wheat, they assume a residue to crop ratio of 1.3, resulting in a residue straw potential of 354 000 000 tons worldwide [34]. As crop residues are by-products of food production they are termed as so-called second-generation feedstock, especially for biofuels production (see e.g., [35]). So far, no world market for straw aimed at industrial applications exists. However, prices can be approximated by calculating production and logistics costs [36]. 4.2.2.5 Other Biogenic Residues Besides the lignocellulosic residues described in Section 4.2.2.4 further biogenic residues accrue. Green plant residues stemming from the maintenance of parks, gardens, cemeteries, or alleys provide a source for lignocellulosic biomass. These cut grasses are usually either shredded and left where they accrue for soil recreation or they are collected and composted, that is, biodegraded by microorganisms. Other possible uses are conceivable in energy generation. This could be performed by combustion after drying, for example by feeding it to incineration along with other organic wastes, or via biogas production through anaerobic digestion ([37], pp. 114–115). Manure originating from livestock keeping mainly consists of animal feces and urine, accruing either as liquid manure to which water might be added or as a mixture with litter, that is, with straw. The specific composition of manure depends on the animal species and on feeding patterns. Liquid manure from cattle or pigs contains about 7–11% dry matter, to which dry organic matter contributes 75–86%. Solid manure from these two species has a dry matter content of about 20–25% with 68–80% of this dry matter being organic. Within these ranges, cattle manure on average contains little more dry matter than pig manure, whereas the organic fraction of the dry matter is somewhat higher for cattle than for pigs. Poultry manure consists of about 32% dry matter of which organic components make up 63–80% ([38], p. 95). Because of significant nitrogen contents (1.1–3.4% of dry
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matter for solid cattle manure, 6–18% of dry matter for liquid pig manure) these agricultural residues are on the one hand traditionally used as organic fertilizer, often on the farm on which they accrue. On the other hand, manure is also a suitable substrate for biogas production and an excess of manure besides fertilizer use can be assumed (for Germany see [39]). Another potential source of biomass is organic waste from households which in industrialized countries delivers a quite diverse mixture of biomass including fruit and vegetable residues, pet excrements, and paper. About 50% of domestic waste can be assumed to be organic [37]. The composition of organic waste from industry depends on the respective sector. Organic residues from agricultural processing were already discussed in the sections above. Domestic and industrial wastewaters also consist of organic matter. Along with microorganism biomass, part of these organics forms the sewage sludge that results from wastewater treatment. The latter is used in agriculture or as a supplement combustible in power plants (see, e.g., [40]). The production of pulp and paper delivers by-products that can principally be recovered and utilized as renewable raw materials. The waste liquor of alkaline pulping, the so-called black liquor contains inter alia acetates, degradation products, soluble alkali lignin as well as saponified rosin acids and fatty acids. Black liquor can be combusted to provide energy for the plant or alternatively yield crude tall oil (CTO) which contains between 15 and 55% fatty acids and 20–65% rosin aids [15]. World production of CTO can be estimated to be about 1.5 million tons [41]. Vacuum distillation allows fractionating CTO into a rosin acid-rich component, known as tall oil rosin (TOR) and a fatty acid rich component, known as tall oil fatty acids (TOFAs). TOR is industrially used as adhesives additive and emulsifying or binding agent, for example, [15, 42]. The TOFA fraction which is rich in oleic and linoleic acid [15] is regarded as a potential vegetable oil replacement for the production of biofuels and oleochemicals. However, sufficient purification is challenging. In Europe, TOFA still containing a rosin acid content is currently produced in Scandinavia as intermediate for the production of alkyd resins, dimer acids, soaps or coatings, for instance [41]. The second important pulping process, sulfite pulping, yields waste liquor containing mainly carbohydrates and lignosulfonates. If recovered, the former can be used to produce ethanol, yeast and xylitol while the latter is applicable as concrete additive, dispersing agent or drilling agent, for instance. In a concentrated form, waste liquor from sulfite pulping is a pelletizing agent in animal feed, coal, and ore production [17]. 4.2.2.6 Algae Algae are a recently widely discussed possible renewable raw material. The term “algae” does not describe a botanically homogenous family but rather a certain group of mainly photoautotrophic organisms that grow in aqueous habitats. They are not even limited to one of the three biological domains, as the prokaryotic cyanobacteria (or blue algae) are traditionally classified as algae, whereas green, red, and brown algae as well as diatoms are eukaryotic organisms. Microalgae are
4.2 Determining Factors for the Logistics of Industrial Utilization Chains
unicellular organisms that have some important merits making them principally interesting for industrial production. They can be grown and harvested during the whole year and be cultivated on otherwise nonarable land by using brackish or even wastewater as cultivation medium [43]. Compared to terrestrial plants they require less water and generally achieve a higher efficiency of solar to chemical energy conversion and the CO2 fixation potential is about 1.7 kg/kg dry biomass [44]. Like terrestrial plants, algae need minerals such as nitrogen and phosphor for their metabolism. Currently microalgae are used as nutrition supplement in special applications like medium quality improvement or the coloring of foods, for example salmon with beta carotene. Nonalimentation applications of microalgae include biofertilizers from biochar and cosmetic ingredients for face and skin care [45]. For industrial processes, microalgae are a potential source for fatty acids, proteins, vitamins, and pigments. Recently, they are also discussed for the provision of biofuels [44]. Besides microalgae, green, red, and brown macroalgae (also called seaweeds) are cultivated or directly harvested from the sea. Industrially important compounds extracted from seaweeds are agar, carrageenan and alginate, hydrocolloids applicable as gelling and thickening agents in food or cosmetics or as cultivation media in microbiology. Other but so far minor applications are feed additives (from seaweed meal) and biofertilizers, whereas research is undertaken to convert them into biofuels [46]. Several cultivation and harvesting concepts are already used or discussed for future implementation. They differ fundamentally from the other renewable raw material production logistics described in this chapter and are therefore not considered further. 4.2.3 Actors and Stakeholders – Mobilization of the Renewable Raw Materials
In general a major difference between logistic chains for fossil and renewable raw materials is the number of actors necessary to “generate” and transport a comparable amount of raw material. This is because renewable raw materials not only have a low yield per unit area and are unevenly distributed in our environment; they are also grown and harvested by a large number of actors. Since this great number of actors is involved, the effort to organize and secure feedstock supply is compared to fossil raw materials significantly higher. Farmers, forest owners, raw material consumers, entrepreneurs, machine operators, administration staff, and workers grow renewable raw materials, harvest them, organize and run logistic chains. Hence, logistics of renewable raw materials is not only about the most efficient combination of machinery and means of transport but also on communication and interaction between the actors. The better the communication and interaction, the lower are transaction costs and the higher the efficiency of a logistic chain. The growers of renewable raw materials are at the beginning of every logistic chain. This group is very diverse regarding size of their farms or forests, cultivated
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crops, age and structure of forest stands, output, technical equipment, sales, objectives, etc. While the large farms usually do have own technical equipment for cultivation and harvesting of crops, even forest owners with a couple of hundred hectares do not necessarily have workers and/or the technical equipment for management operations such as thinning and felling. Only the large state-owned forest enterprises as well as large private forest owners do have staff and technical equipment as well as an administration with sales department. While smaller farmers are often organized in cooperatives for the joint marketing of their crops or in machinery syndicates, the majority of small private forest owners, however, are not organized at all and hardly have access to timber markets. From an industrial utilization chain perspective business with large farmers or forest owners as well as cooperatives is the most convenient option. They can deliver reasonable amounts of renewable raw material, have the technical means to harvest the raw material and possibly deliver it at the factory gate. Efforts for communication and administration are comparably small. Although this might be the preferred option, in many countries it is the small farmers that produce the greatest share of crops and the small private forest owners that have the biggest unused wood potentials. To secure feedstock supply their crops and their timber might be needed too. There are two principal concepts for raw material acquisition from these small farmers and small private forest owners. First, harvesting and transport of the renewable raw materials as well as coordination and administration of the logistic chains is under own control. This ensures for maximum flexibility and minimum raw material acquisition costs on the one hand, but on the other hand, administration and transaction costs are rather high. Second, harvesting and transport of the raw materials as well as coordination and administration is realized by contractors. Contractors are responsible for in-time delivery of the raw material at the factory gate. They are contractors to farmers and forest owners. Contracts are made between contractors and farmers/small private forest owners and between contractors and forest industry. From an industrial utilization chain perspective transaction and administration costs are lower compared to the first concept due to the smaller number of actors involved. Raw material acquisition costs however are most likely higher since the contractors need to recover their costs. A thorough analysis of the farmers and forest owners’ structure, availability of contractors, type of feedstock, size of the plant, infrastructure, etc., determines which principal concept to choose and how to adapt it to the local circumstances. Independently of the chosen concept, reliability and trust between actors as well as transparency of all procedures related to the logistic chain are key factors for smooth operations. Modern communication technology and standard communication routines ensure maximum transparency. GPS maps ensure easy finding of the raw material for example in the forest, and raw material tracking systems ensure control of material flow as well as allocation of the raw material back to farmers and small private forest owners. The latter is a precondition for correct and prompt billing. An issue especially relevant for timber is its mobilization. In contrast to farmers who generate an annual income with their crops, small private forest owners
4.3 Processing Steps of Renewable Raw Material Logistic Chains
do not with timber sales. This is because felling takes place every 5 to 10 years and small private forest owners have hardly access to timber markets. In many cases timber sales even do not fully compensate the harvesting costs. Hence, the biggest unutilized wood potentials can be found in the forests of small private forest owners, while at the same time their interest to mobilize timber is rather low. In the light of future increasing timber demand, it is necessary to mobilize these potentials and make them available. This already has been recognized by public authorities and forest industry in many countries throughout Europe. In Germany, for example, there are financial incentives in place for the foundation of forest owners associations to facilitate market access as well as direct support by state forest authorities regarding forest management and marketing of timber.
4.3 Processing Steps of Renewable Raw Material Logistic Chains
Following the presented determinants of renewable raw material logistic chains, processing steps for cultivation and harvesting, transport, and storage of renewable raw materials have been elaborated throughout the centuries. As the renewable raw materials differ to a large extent as well as the environments in which they are cultivated and harvested and the actors involved manifold options and a large variety of suitable machinery exist. In the following, we therefore describe the main processing steps for the most important types of renewable raw materials as they are practiced in Central Europe. It is not our aim to describe these steps in detail but to point out the most important issues from a logistical point of view. For detailed descriptions of technical processes we refer to references. 4.3.1 Cultivation and Harvesting for Selected Types of Renewable Raw Materials 4.3.1.1 Agricultural Production The configuration of an agricultural production is dependent on the crops to be grown as well as the conditions provided by the environment where growth should take place. Every crop has specific demands regarding soil- and climate-related factors such as nutrients, water, or temperature. Some references to this were already made in Section 4.2.2. Besides, plants also differ in the length and in the timeframe of their life cycle. They are accordingly classified as annual, biennial, and perennial if they grow for one, two, or more growing seasons, respectively. In Europe for instance, winter wheat is sown from end of September till end of October and harvested in July and August. Summer wheat on the other hand is sown in spring and harvested in summer. All these characteristics need to be taken into account if decisions for crop production are to be made or if production potentials are to be estimated.
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Furthermore, the fundamental principle of crop rotation underlies commercial agriculture [47]. Unlike in untouched environments where several species share a habitat, agricultural fields are planted with monocultures for one entire life cycle of a crop. As this exhausts the soil and makes plantations vulnerable to weeds and pests, natural diversity needs to be simulated by a systematic seasonal sequence of different crops. Cover crops (e.g., mustard) can be grown to close gaps in the sequence and to support soil recreation. The latter effect is also created by the incorporation of set-aside land into the crop rotation. Once this basic framework is set up, more detailed planning of the agricultural value chain can be performed. In the following, some general aspects concerning tillage, sowing, cultivation, and harvesting of agricultural goods are described. Tillage and Sowing Before a new crop can be sown on a harvested field the acre has to be prepared by different mechanical operations. Burying of crop residues, loosening, aeration, mixing of soil and fertilizer, mechanical weed control, and seedbed preparation are achieved by the use of specific tools, first and foremost ploughs, but also harrows, field cultivators, rollers, and other devices. How and when these measures are performed depends on the type of soil and the crop rotation, that is, on the previously grown crop and the actual crop to be sown. The process of sowing is the initial step of a crop’s life cycle. It can start when the seedbed is prepared. For all major crops, different cultivars are available on the market so that the most appropriate one for the general parameters can be selected. Depending on the legal framework, genetically modified plants can also be considered. The optimal point of sowing generally depends on the cultivar though it is influenced by short term weather fluctuations and in practice will also be chosen by experience of the farmer. Other species- and cultivar-related parameters are the width of the rows, the depth of sowing and the quantity of seeds per hectare. Cultivation – Fertilization, Irrigation, and Crop Protection Although the metabolism of a field crop is based on sunlight, carbon dioxide from the atmosphere, nutrients from the soil and groundwater as well as precipitation, addition of nutrients usually increases the yield and supports soil recreation. Fertilization is therefore an important step in agricultural production. Essential nutrients for plants are nitrogen, potassium, phosphor, sulfur, calcium, magnesium, and other metals. They are brought to the field as inorganic fertilizers, normally once during a growing season. Negative environmental effects especially of nitrogen fertilizers play an important role in the assessment of renewable raw materials sustainability [48]. Mineral fertilizers are supplemented or, in organic farming, totally replaced by organic fertilizers (see Section 4.2.2). In some agricultural regions, the use of irrigation schemes can be necessary to ensure sufficient water supply. While this plays a minor role in Central Europe, some countries like Israel are highly dependent on irrigation to sustain their agricultural output. Implementation of crop rotation and tillage alone does not prevent the occurrence of pests on the field. If additional mechanical operations are not sufficient, not wanted for economic or environmental reasons or not possible because of
4.3 Processing Steps of Renewable Raw Material Logistic Chains
negative effects on the soil, the use of chemical agents becomes necessary. These plant protection products are classified according to the pest they ought to suppress. Weeds, that is, herbs and grasses considered as undesired for the growth of the crop, can be controlled or eliminated by the use of herbicides. Fungi are controlled by fungicides, insects by insecticides, nematodes by nematicides, and so on. In the United States, the Environmental Protection Agency (EPA) is responsible for the approval of pesticides, while in the EU, a joint process between Union and member states regulates the use of plant protection products. For each crop, only a limited number of products are accredited and for some species, no pesticide is allowed at all. Harvesting and Conditioning Harvesting and conditioning are central steps in agricultural production. Though the processing chains for harvesting and conditioning of agricultural products differ to a large extent, two major types can be distinguished. A differentiation can be made between stem-like renewable raw materials, such as maize, cereals, oil crops and grasses as well as root and tuber crops such as sugar beets, potatoes, or topinambur. To harvest stem-like renewable raw materials these have to be cut, if necessary threshed to separate the fruits/grains from the chaff, if applicable also preprocessed, for example, packed as bales, chaffed, or pelletized (see Section 4.4.2). As a result, these raw materials come as bales, chaff, pellets of whole crops or straw as well as seed grain or straw. Finally the renewable raw materials are either transported to a plant or stored (see following sections). Figure 4.1 gives an overview of the named processing steps. To carry out these steps one- or multiple-step harvesting can be applied. To harvest whole crops with different grades of ripeness a multiple-step harvesting with for example, a cutting and drying in swaths and following collection, threshing and separation can be applied. Problematic are the comparatively high losses of grain during the drying on the fields [49]. Therefore, combine harvesters are also used to gain the seed while only the chaff remains at first on the fields.
Crops
Whole crop
Collection & processing
Straw
Collection & processing
Bale
Cutting Chaff Threshing + Seperation
Recycle to soil Seed
Collection
Figure 4.1 Processing steps for the harvesting of stem-like crops.
Pellets
Seed
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When a homogeneous ripening is ensured a harvesting in one step, for example, with a forage harvester with cutting unit, hay baling presses or pelletizing machines is possible. Depending on the type of renewable raw material the used machinery has to be adapted to meet the requirements of for example, toughness, diameter, and height. For details concerning the applicable machinery we refer to according works on agricultural machinery such as, for example, [50, 51]. Short rotation crops are harvested similarly. In these cases, maize harvesters are equipped with special cutting units. For root or tuber crops the harvesting is split into leaf removal, grubbing, cleaning, and collection of the tubers and leafs if applicable. Leafs are either chemically, for example, for potatoes or topinambur, or mechanically removed by a cutting step. Leafs usually remain on the fields and are plowed in or collected and pressed to bales as well as chaffed. With up to 40–50 tons dry matter per hectare for sugar beet and 6–8 tons dry matter per hectare for topinambur these are promising options for the named raw materials (see [52]). The roots or beets and the bales and chaff are stored or transported directly to the further processing. Figure 4.2 gives an overview of the main processing steps. Usually, the steps are carried out in two phases. For sugar beets also a one-phase beet harvester can be applied. Though the processing chains are in general similar for the three named types of root- or tuber-like raw materials, different equipment is used. For sugar beet the precision of the cutting of leafs is of special importance for the harvesting efficiency since wrong cuts can lead to high losses of yield. For potatoes and topinambur the grubbing has to process large amounts of soil. For details concerning the used equipment and processing steps we refer again to works on agricultural machinery. Besides the named threshing, chaffing, baling especially cleaning, and drying can take place before long-distance transports (see Section 4.3.2) or utilization of the agricultural raw materials are carried out [53].
Grubbing
Beets / Tuber
Cleaning
Tuber
Collection
Tuber
Collection & processing
Bale
Leaf removal
Leafs Chaff Recycle to soil
Figure 4.2 Processing steps for the harvesting of beets and tuber.
4.3 Processing Steps of Renewable Raw Material Logistic Chains
Summarizing, it can be stated that there is not the one-for-all solution for an agricultural production chain with the highest productivity and the lowest costs. The determination of the applicable process chain is depending on the particular raw material, the environment, and the available machinery. Cost data for the calculation of agricultural production costs are published, for example, by the German Association for Technology and Structures in Agriculture (KTBL) and can be found in [54]. 4.3.1.2 Forest Production Unlike the production of annual agricultural crops forest production lasts several decades. Depending on tree species and forest management regime rotation periods (time between stand establishment and final cut) of 80 to 200 years are common practice in European forestry. The time span between management operations usually averages a couple of years. Hence, compared to agriculture input of energy, machinery and materials are low for forest production. The following chapters give a short description of the major steps of forest production and have a closer look on the technical concepts of timber harvesting in Central Europe. Stand Establishment In general, there are two options for stand establishment in high forests: planting or natural regeneration. After clear cut or storm felling stand establishment usually takes place with plants that have been raised in tree nurseries. Depending on the tree species and site conditions 1500–25 000 plants per hectare are manually or mechanically planted. In Central Europe, soil preparation is only necessary if the soil has thick grass or humus cover. Planting leads to evenaged stands unless a second “stand story” is introduced at a later stand age. In continuous cover forestry and close to nature forestry natural regeneration is the common method of stand establishment. Natural regeneration is a continuous process and hence leads to uneven-aged stands with two or more stand storeys. In order to induce and support natural regeneration the stand canopy needs to be opened and sometimes soil scarification is necessary. Tending and Precommercial Thinning Tending and precommercial thinning are performed as an average between stand ages 5 and 20 years in softwood and 10 and 40 years in hardwood stands. Both aim to eliminate trees of bad quality, to reduce the number of seedlings in natural regeneration, and to support good quality as well as fastest growing trees. Tending and commercial thinning are performed either motor manually or fully mechanized. Due to their small diameter the trees felled are not merchantable and left in the stand. Harvesting Harvesting of merchantable wood starts in softwood stands as an average at stand ages of 25–30 years, in hardwood stands some 10 to 15 years later. Until the final cuts, thinning is performed to support the highest quality and fastest growing trees. In even-aged high forests final cuts start when a stand reaches maturity. In the boreal zone, the tropics and many countries elsewhere
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final cuts are clear cuts whereas in Germany clear cuts are either prohibited or limited by size. In close to nature managed stands, however, a distinction between thinning and final cut is not possible since with each cut young as well as mature trees might be felled. The technical options to perform a thinning or final cut are numerous. Depending on the natural factors like tree species, stand age, topography, soil, etc., mentioned in Section 4.2.1, a great variety of machines and working procedures can be combined. If all other factors are equal, the performance of any harvesting chain depends first and foremost on the mean breast height diameter of the trees to be felled. The bigger the trees, the higher is the performance of the harvesting chain per working hour. Since logs as well as wood chips are potential feedstock for industrial valorization chains of renewable raw materials such as biorefineries or second-generation biofuels, special attention is given to harvesting chains for logs and wood chips (see Figure 4.3). The purpose is not to show all possible process variations and details but to show the major differences between the harvesting chains. The partially mechanized harvesting chain is often applied by small private forest owners and farmers since the necessary equipment is comparably cheap and easy to handle. However, in hardwood stands with large diameter trees partially mechanized harvesting is still the only viable working procedure since tree harvesters cannot handle large diameter trees yet. A partially mechanized harvesting chain for log production typically consists of 2–3 steps: 1) 2) 3)
motor-manual felling, delimbing, and cut to length with chainsaw; manual forwarding and piling of small diameter logs (1–2 m length) at skidder trail; and forwarding of logs by forwarder or skidder to forest road (small and large diameter logs).
Living tree
Full length tree
Raw shaft
Log Stand
Skidder trail
Forest road
Figure 4.3 Pictogram of a partially mechanized harvesting chain for logs.
4.3 Processing Steps of Renewable Raw Material Logistic Chains
Fully mechanized harvest chains are compared to partially mechanized chains generally more productive and harvesting costs per m3 are, despite the higher system costs per working hour, overall lower. Fully mechanized harvesting chains are mainly applied for thinning and final cut in softwood and increasingly for thinning in younger hardwood stands. The machines generally are operated by entrepreneurs with special training for timber harvesters. A fully mechanized harvesting chain consists of two steps (see Figure 4.4): 1) 2)
felling, delimbing, cut to length and piling by harvester on skidder trail; and forwarding by forwarder to forest road.
As for logs the production of wood chips can be done either partially or fully mechanized. Wood chips either can be coproduct of log production or main product. This very much depends on the demand and prices for logs and wood chips as well as the quality and average stem volume of the stand to be harvested. If wood chips are main product of log production, a typical partially mechanized harvesting chain consists of three steps (see Figure 4.5): 1)
motor-manual felling with chainsaw;
2)
forwarding of full length trees or logs by skidder to skidder trail or forest road; and
3)
chipping of full length trees or logs with mobile chipper on skidder trail and forwarding of chips to forest road or chipping of full-length trees or logs with mobile chipper at forest road.
A fully mechanized harvesting chain for wood chips as the main product has maximum three steps (see Figure 4.6):
Living tree
Full length tree
Raw shaft
Log Stand
Figure 4.4
Skidder trail
Forest road
Pictogram of a fully mechanized harvesting chain for logs.
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Living tree
Full length tree
Full length tree
Wood chips Stand
Skidder trail
Forest road
Figure 4.5 Pictogram of partially mechanized harvesting chain for wood chips.
Living tree
Full length tree
Wood chips
Wood chips Stand
Skidder trail
Forest road
Figure 4.6 Pictogram of a fully mechanized harvesting chain for wood chips.
4.3 Processing Steps of Renewable Raw Material Logistic Chains Tops, branches slash
Wood chips Stand
Skidder trail
Forest road
Figure 4.7 Pictogram of fully mechanized harvesting chain for wood chips from tops,
branches and slash.
1) felling and chipping on skidder trails with special chip harvester or felling and forwarding to skidder trail with harvester; 2) forwarding of chips with shuttle to forest road or forwarding of full length trees or logs to forest road; and 3) chipping of full-length trees or logs at forest road. As a coproduct of log production, wood chips are made of the remaining slash that consists of tops, branches, and low quality parts of a stem. The two-step harvest chain in general is fully mechanized and looks as follows (see Figure 4.7): 1) 2)
collecting of slash and hauling to forest road with forwarder; and chipping at forest roadside.
The question which harvesting chain in general has the highest productivity and lowest costs cannot be answered per se. Calculations by [55, 56] for different wood chip harvesting chains and different stands in Germany show that the natural factors very much determine the best solution for a certain stand. And even if the best solution for a certain stand could be identified, one usually has to operate with the machines that are available and try to optimize their employment. 4.3.2 Transport
Transport processes are the link between renewable raw materials production sites, storage places, and the consumers. Unlike fossil raw materials renewable ones are not concentrated in large amounts at a few places. Instead renewable raw materials are scattered in relatively small amounts per unit area. Hence, the effort for harvesting and transport of a comparable amount of renewable raw material is manifold concerning machinery, persons, coordination, and costs involved. Depending on the distances that need to be bridged, infrastructure and flexibility needed, different transport means are available.
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For raw material transport from a field or forest to a nearby storage site or consumer tractors or trucks are the preferred means of transport. Both can access fields and forests via field tracks or forest roads. They are able to transport any agricultural crop as well as timber but their transport capacity is limited. The limits are set by the accessibility of the production site as well as by legal regulations regarding the maximum payload. Since there is almost always no backhaul from storage site or consumer to a field or forest, overall capacity utilization in general is 50%. This implies that transport of low-value raw material by tractor or truck over long distances is economically nonviable (see [57]). For most agricultural crops as well as wood chips transport with roll-on or skip containers is most flexible and efficient. Three or four containers per truck reduce inefficient loading time since one or two containers placed at the production or storage site can be loaded, while the truck with the other containers is on its way to the point of delivery. After return from the point of delivery, the containers are exchanged and the transport cycle starts again. If a container at the point of delivery needs to be moved from truck to train or ship, this can be done with standard container handling equipment available at any container terminal. Due to time-table limitations and time-consuming shunting, overall transport speed of trains is comparably slow. Hence, trains are mainly used for long-distance transport of large quantities. For train transport a great variety of different wagons are available. There are stanchion wagons for log transport, different types of intermodal and container wagons as well as open and closed freight wagons for agricultural crops, small-sized logs and wood chips [58]. The wagon type to choose depends on the type of raw material as well as the loading and unloading equipment available at the shipping terminals. Block trains with fixed time schedule on fixed routes or especially to customer needs scheduled block trains are the fastest option for renewable raw material transport by train. Compared to single wagon trains that consist of groups of wagons with different places of departure and destination, block trains have several advantages: the overall transport speed is faster; there are no shunting stops; there is no coupling and uncoupling of wagons; freight costs are rather fix; use of private owned wagons is possible. Hence, block trains are increasingly used by industries with a high demand and throughput of feedstock. Transport by ship is an option when transport speed is not an important issue or ships are the only means of transport for example, in intercontinental transport. For river transport, the high freight capacity and the comparably low transport costs are in contrast to the very few landings along rivers. Since the raw materials normally need to be transported from the production site to the landing and from the landing to the final destination, river transport is competitive against road transport on distances longer than 250 km [59]. In 2008, more than 10 million tons of agricultural and related products3) were transported on inland waterways [60]. Transport capacities depend on the type of vessel and range from small motor vessel with some hundred tonnes to push convoys consisting 3) This includes wood.
4.3 Processing Steps of Renewable Raw Material Logistic Chains
of a pushing vessel and one or several barges with more than 16 000 tonnes deadweight. However, for transport between continents or large distances ships are the only option for renewable raw materials transport. Millions of tons of agricultural crops like cereals, oil fruits, sugar, palm oil, as well as wood are shipped every year. There is a great variety of ships regarding type and deadweight. The sizes of general cargo vessels, dry bulk carriers, tankers, container vessels range from a couple of thousands to several hundred thousand tons deadweight. The type of freight, the loading equipment at the port, port charges, etc., determine the optimal size of a vessel [61]. For transport close to coast coasters with a couple of thousand tons deadweight are standard. The so-called Handymax carriers with 35 to 60 thousand tons deadweight, Panamax carriers still allowing passage through the Panama channel with 65 to 80 thousand tons deadweight and finally even bigger tankers and container vessels are used for transport across open sea. Transport costs depend very much on the route and are negotiable. Two factors that are of special concern for transport of renewable raw materials are density and water content of the raw material. This especially holds true for wood, straw, and grasses. Due to the low density of these raw materials usually maximum payload cannot be reached even when the material is compressed before transport. If in contrast the water content of renewable raw materials for example, of logs or wood chips is rather high, it is not possible to fully utilize the maximum transport volume. The following example may highlight this. Although the maximum transport volume of a container truck in Germany is 80 m3 and the maximum payload is 22 tons, only 11 dry tonnes or 49 m3 of wood chips can be transported if the water content is 50%. Hence, the lower the water content, the lower the transport costs per ton dry matter. 4.3.3 Storage
In general, storage is an important process step in renewable raw material logistics chains as it fulfils different functions. Storage can ensure the supply of a processing plant with feedstock by a temporal balancing of harvest and utilization. Also transport amounts can be balanced by collection of renewable raw materials until transport amounts for trucks, trains, or ships are reached. A further function of storage can consist in the conditioning of the raw materials, for example, by air drying of straw or wood. Storage can be carried out at the place of harvesting, that is, in the forests or on the fields, in transfer storage places or at the point of utilization. The individual configuration and placement of the storage and – if necessary the needed facilities – is dependent on the specifics of the particular utilization chain, especially the environment, the raw material characteristics and the specific harvesting, transport and utilization steps. Storage of renewable raw materials comes along with several risks concerning loss of dry matter and quality. Depending on the type of raw material, its water
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content and the conditions of the storage the loss of dry matter makes up between around 1% per year for pole wood and 30% per annum for wood chips [62]. The growth of fungi and spores, bacterial activities, spontaneous-heating and in the case of agricultural raw materials the damage caused by animals such as mice and rats cause these losses. Further storage risks result from the danger of auto-ignition, due to the spontaneous heating, environmental effects such as odor, spores, and water effluents. From a quality aspect advantages of storage such as the drying, which leads to higher specific heating values and lower transport loads come along with quality losses due to rainfall, frost, fungi and bacteria as well as physical effects. The vulnerability concerning such risks can be dependent on the state of the raw material. Damages through harvesting and preprocessing to the surface of for example, sugar beets can intensify these effects [12]. Storage facilities can be distinguished into outdoor or indoor storage. Outdoor storage is possible with soil and weather protection by for example, wood, concrete or bitumen base, and foil. Thus, pollution or rehumidification can be avoided. An outdoor storage without weather protection is common practice for unconditioned wood [63]. For indoor storages, old buildings, storage halls, or silos can be used. Stock loading and removal are important facilities needed for renewable raw material storage. For details concerning the technical possibilities we refer to [62].
4.4 Design and Planning of Renewable Raw Material Logistic Chains
In the previous sections, the particularities of renewable raw materials concerning common and specific determining factors like the natural environment, the raw material characteristics, and actors and stakeholders as well as technical aspects of the logistics chains have been discussed. Induced by these factors, specific aspects have to be regarded in design, assessment and planning of renewable raw material-based logistic chains. In the following we point out the aspects of the determination of plant sizes, facility location planning and the determination of the structure of renewable raw material-based logistic chains, the consideration of competing utilization pathways and – as a consequence – the demand for an integrated assessment and planning. 4.4.1 Determining Plant Sizes: Economies of Scale vs. Minimization of Transport Load
The described specifics of renewable raw materials-based logistic chains increase the importance of an integrated consideration of economies of scale and transportation costs. Economies of scale denote the phenomenon that under the assumption of a complete capacity usage-specific production costs and the investment per capacity unit decrease with rising capacities.
4.4 Design and Planning of Renewable Raw Material Logistic Chains
For single aggregates this effect is usually quantified using the following equation: Cap I = I0 Cap0
n
I : Investment [Monetary Units] for an aggregate of capacity Cap [Capacity Units] I 0 : Investment for an aggregate of capacity Cap0 [Capacity Units] n: Scaling exponent [−] For single aggregates economies of scale are caused by decreasing investment expenses due to decreasing production costs for larger equipment. Concerning whole process chains also additional effects can be observed which can be determined for example, in cost structure analyses (see, e.g., [64]). Besides scale-up effects for main and secondary components, degressive cost behavior can also be found for installation, storage, engineering, spare parts handling, licenses, interests, and plant start-up. Especially installation costs show a strong declining cost increase and process measuring and control technology is often to a large extent independent of plant capacity. Of course, determining economies of scale by the given equation is a simplification. Accordingly, the usage of such estimations has often been criticized. Up-scales are limited due to capacity restrictions or other reasons, for example, production flexibility. It is often problematic to find a single measure to determine investments dependent on the capacity. Besides production capacity or volume, pressure, temperature, materials, and other factors have to be regarded. Further, the link between the characteristic dimensions and the thus determined production and material costs of aggregates and process chains on the one hand and the prices on the other hand is not direct as a market exists on which equipment manufacturers compete. Nevertheless, economies of scale describe the reason why engineers often tend to design and build rather few large scale plants instead of a higher number of smaller plants. This contradicts the aim to minimize the transport load of the renewable raw materials. An increasing demand for renewable raw materials, also induced to competing utilization pathways (see Section 4.4.3), will have price effects on the market. This is enforced as usually regional supply is intended: Renewable raw materials have – in comparison to fossil raw materials such as coal and natural gas – a low specific calorific value with regard to their weight. This makes long-distance transports unfavorable from an economic as well as from an ecological point of view. On the one hand the named price effects will cause an increase in costs for the biomass. On the other hand this biomass will most probably have to be transported for longer distances as the area which has to be harvested has to be increased with in many cases decreasing yields. Thus, the costs for transport increase overproportionally with an increase of the plant capacity. Wright and Brown show this for example, for a renewable raw material conversion plant in the center of a circular supply area [65]. The price effects of the increased demand have to be considered in addition. Long-distance transports may also require further reloading steps.
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To account for these contrary effects of economies of scale a decoupling of the renewable raw material logistics chains can be carried out. Decoupling means a subdivision of the process chain in processing steps which can be carried out spatially or temporally separated. Spatially decoupled means to locate some processing steps close to the place of occurrence of the raw material and thus producing intermediates which can be transported at better conditions. Spatially decoupled processes can start with preparation, for example, grinding and milling of wood in the forest or the preparation of crops on the field, to achieve a higher bulk density and leave not needed parts of the harvest in the forest and on the fields. Further possibilities are drying and conditioning of the renewable raw materials at small decentralized plants to achieve intermediates with a higher volumetric calorific value. Thus, the economic transport distances for the renewable raw material are increased significantly and long-distance transports become possible. Such concepts are followed by different actors, for example, by the Karlsruhe Institute of Technology (KIT) in the so-called bioliq concept for the production of synthetic fuels or platform chemicals from lignocellulosic biomass (see, e.g., [66]). The viability of such a concept is dependent on numerous factors. First of all, such a decoupling has to be possible from a technological point of view. Such a decision is further influenced by the used feedstock. Feedstock price, chemical and physical properties such as density, chemical composition, water content as well as yield and spatial distribution of the cultivation areas have to be considered. The named factors determine the requirements concerning the scope of the preparation and conditioning units, if, for example, grinders or mills, dryers, pyrolisis plants, etc., are needed to achieve a transportable intermediate. The existing road network, rail connection, or vicinity to inland or sea shipping ports have also to be regarded as well as the choice of the plant sites (see Section 4.4.2). All these factors together determine whether a central integrated concept or a decentralized decoupled concept is economically and ecologically favorable. Therefore, for example, different concepts are followed by two pilot plants for biomass-to-liquid fuel production from lignocellulosic biomass in Germany. Whereas the KIT concept uses the described decentralized approach, aiming mainly on the utilization of residual straw in Baden-Württemberg (see [57]), the CarboV process by Choren Industries follows a central integrated approach based on wood (see [67]). In temporally decoupled processes certain processing steps are seperated and dimensioned differently. Parts of the process chain are operated only partly throughout the year, while others run continuously. The parts of this process chain are linked through large storage facilities. The idea is to produce better storable intermediates. Thus, it can be accounted for seasonal effects and temporal storage limitations. Examples of such decoupling approaches can be found for example, in the sugar industry. Due to storage restrictions the processing steps to gain the thick-juice are larger dimensioned than the rest of the plant. Thus, the sugar beet harvest is converted quickly into thick-juice which, at good storage conditions, has only limited degradation effects. The following steps of sugar refining are carried out throughout the whole year in a smaller dimensioned plant.
4.4 Design and Planning of Renewable Raw Material Logistic Chains
4.4.2 Facility Location Planning and Determining the Logistical Structure of a Renewable Raw Material Utilization Chain
An important role in the planning and design of a valorization chain for renewable raw materials plays the selection of the plant site. Already the early works in this field by von Thünen deal with the allocation of agricultural production (see [68]). Several authors have compiled catalogs with plant site selection factors, describing the complex interdependencies of numerous external factors on the selection of suitable locations for the processing plants. These comprise parameters that should be considered in the selection process. Besides general aspects such as property and soil, traffic and transport, production, investment and financing, common infrastructure, labor, procurement and disposal, demand, public authorities, and personal preferences for particular factors have to be considered concerning utilization pathways for renewable resources. While we refer for the common factors, which can differ in their importances for renewable raw material valorization chains, to related literature (see, e.g., [69]), we describe important particularities in the following. To achieve economies of scope, that is, cost decreases through a bundling, an integration of renewable raw material conversion plants or utilization chains into existing sites, plants or logistical structures can be advantageous. Thus, it is possible to reduce the outside battery limits investment, use built infrastructure, facilities, and logistical processes. Operating costs may decrease, especially for plant-specific overheads and lower prices for for example, steam, electricity, heat, and cooling. In principle, such an integration can be carried out in two directions, supply or product oriented. A supply orientation, that is, an integration into raw material logistics chains or plants for wood and crop processing is favorable when the feedstock needed in a biomass conversion chain accrues as a by- or waste product or the same logistical structure can be used. Suitable examples for existing renewable raw material logistic chains are for example, saw mills, oil mills, pulp, and paper plants. The advantages of such a concept lie in reduced costs for feedstock and its transportation due to an integration into established feedstock provision structures and the potential use of residues. Further advantages can be achieved through symbiosis with the plant where by- or waste products accrue as storage and utilization problems might be solved and energy demands and surplusses of different plants can be combined. Disadvantages may arise through feedstock competion and as the dimensioning of the plant is – at least to some extent – dependent on the dimensioning of the existing plant. In a product-oriented integration, the renewable raw material valorization concept is integrated for example, into an existing refinery or other chemical production site. This has advantages through a close vicinity to possible further utilization, for example, when building blocks are produced in the biomass valorization process that can be used further within the refinery or other chemical production site. Thus, storage capacities and distribution logistic efforts can be reduced. This is favorable for example, when the products of the valorization process are soluted.
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In cases where final products are produced, the distribution logistics can be used. This is favorable especially when similar products like for example, base chemicals or fuels are the main outcome of the process. Disadvantages of such a type of integration lie in a tendency to higher transportation efforts for the feedstock (see Section 4.4.1). If the above-mentioned integrations are not possible or not wanted a building of a plant at a new site is also possible (greenfield scenario). This has the advantage of being built totally to the needs of the renewable raw material utilization process. Disadvantageous is the fact that the new infrastructure has to be built up from the scratch. The logistical conditions concerning harvesting and transport also play an important role, both, in the integration as well as the greenfield scenario. The needed amounts for feedstock have to be harvested and collected. Especially for wood, not every possible source is suitable as catchment area. Steepy hillsides, unsufficient road infrastructure or nature protection areas are exemplary reasons for this. After collection the renewable resources have to be transported to the plant site and the products have to be distributed. This requires enormous transport amounts as plant sizes of 400 000 up to more than 2 000 000 tons of renewable resources (dry matter) are often envisaged when speaking of biorefineries or biofuel production plants. A BtL concept based on a capacity of 750 000 tons dry biomass, for example, wood chips with 50% water content, that is, 1 500 000 tons with 50% water content, would lead to more than 68 000 truck loads per year or nearly 190 truck loads per day.4) Transport by rail would need approximately 1225 trains per year, transport by inland water transport approximately 1550 ship loads.5) Thus, it has to be ensured that the transport infrastructures are sufficent for the planned concept at the given location and also acceptable for further stakeholders. To address the logistical issues of potential analyses, transport infrastructures geographical information systems can be used (see Section 4.4.4). 4.4.3 Consideration of Competing Utilization Pathways
The planning of renewable raw material logistic chains demands for a consideration of competing utilization pathways for the renewable raw materials. This competition is manifold, as competition concerning resources, technologies, and products has to be accounted for. Still opportunities for the investigated new processes for a material or energetic use of renewable resources exist. Nevertheless, there is and in future will be an enforced competition of these investigated utilization chains concerning resources. Utilization chains based on agricultural (main) products are in a competition with 4) We assume a maximum transport load of 22 tons per truck (see Section 4.3.2).
5) We assume a transportation load of a train of 1224 tons, and of an inland waterway transport ship with 974 tons (see Section 4.3.2 and [57]).
4.4 Design and Planning of Renewable Raw Material Logistic Chains
the food chain, directly about these products or at least indirectly about the land use. The land use competition is enforced with the abolishment of a compulsory amount of set-aside land by the EU. So far these amounts could be used for the cultivation of renewable raw materials for industrial purposes. Besides the economic and ecological aspects of these ethical aspects of such a usage have to be discussed. While for Western and Central European countries a surplus of produced food may reduce such objections they are major issues for countries with scarce arable land and unsecure food supply. For forest-based utilization pathways there are also well-established competitors. The pulp and paper industry, wood industry, saw mills, energy plants, and private households already consume large amounts of wood (see Section 4.2.2.4). Many of the utilization chains which are currently developed compete between them as well as with already established or enforced usages of the same resource. One example is the use of lignocellulosis which can be used in lignocellulosic feedstock biorefineries, thermochemical BtL, and SNG processes as well as for heat and power supply in power plants and households. As there is no direct competition with the food chain in this case the possible ethical issues of forestbased utilization pathways appear to be minor as long as a sustainable use of the forests is ensured. However, due to the increasing demand for food and renewable raw materials there is an intense competition about land between agriculture and forestry. In countries without a legal framework that prevents conversion of forestland into agricultural land large areas of forests are being converted. This is because agriculture is usually more profitable. On the output side renewable raw material utilization chains compete against established products and have, at least in a long term perspective, to be competitive with these. If subsidies and tax exemptions are neglected, production costs of such products have to allow to sell these products at the same prices as the competitors, perhaps with small additions for ecological or functional benefits as they can be found, for example, for organic food. The named competition exists also concerning the ecological and social performance of the utilization chains. In order to justify subsidies or tax exemptions for the development and implementation of processes or a differentiation against competing products, these benefits have to be demonstrated. To sum up, utilization chains for renewable raw materials have to prove their effectiveness in terms of economic, ecological, and social performance against their fossil-based competitors as well as against possible other renewable raw material-based utilization chains, for example, aiming to source the same raw materials or producing the same or similar products. When thinking of scenarios in which the investigated renewable raw material utilization chains will become economic it has to be considered that the price of fossil resources affecting the prices, for example, for fuel, is not the only influencing factor. It needs to be considered too, that there are linkages between the prices for fossil resources and those of renewable raw materials (see, e.g., [70]). Thus, the whole system of fossil and renewable raw materials, processes, products, and markets has to be considered.
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4.4.4 Demand for Integrated Assessment and Planning Methods for Renewable Raw Material Logistic Chains
Summarizing, it can be stated that development and implementation of renewable raw material logistics chains requires an integrated assessment and planning under agro- and forest industry, technological, economic, ecological, and social aspects. The utilization chains should not be regarded isolated but have to be seen in the context of existing and further developing pathways and their possible interlinkages. The particularities of the renewable raw materials as described in this chapter have to be reflected as well as the technical requirements of the utilization processes for the scope of the whole value chain. As a consequence, a wide variety of methodologies come into play for an integrated assessment. Potential analyses for single raw materials or utilization pathways have been carried out with geographic information systems (GIS) (see e.g., [71, 72]). Basically, these analyses combine statistical data (e.g., rainfall, productivity, land use) with spatial information. As a result potentials of different raw materials are presented on maps. Further studies include aspects of facility location planning, for example, for bioethanol (see [73]) or BtL plants (see [74]). Material and energy flow analyses with material flow analysis tools and flow sheet simulation systems are carried out to assess as well as to balance and configure technical processes. Economic evaluations are based on the results material and energy flow analyses. Examples for such works are [39, 75]. To determine investments and raw material, energy and total production costs as well as revenues static and dynamic investment calculation methods are carried out. Material and energy balances are as well the basis of ecological assessments. These should not only focus on possible achievements concerning reductions of greenhouse gases or primary resource consumptions but also on other environmental impacts too. Life-cycle assessment (LCA, see ISO 14040 and 14044) is the tool to do this. LCA quantifies and evaluates a number of environmental impacts caused by products, production systems or services. Contrary to other concepts, like for example, the carbon footprints or CO2 abatement costs LCA provides the possibility to cover ecological issues more comprehensively and differentiated. GIS-based analyses are also used in facility location planning, for example, for bioethanol plants [73] or BtL plants [74]. Additionally operations research provides a large toolset for the mathematical characterization, formulation, and solution of facility location planning problems and supply chain design. Overviews can be found, for example, in [76, 77]. Examples for applications to the industrial valorization of renewable raw materials can be found in [39, 40, 78]. Some works combine both approaches (see, e.g., [79, 80]). In those assessment tasks where technical, economic, ecological, and social criteria have to be regarded there are usually no clearly dominating alternatives. Hence, solutions clearly superior to all other alternatives are unlikely. Advantages and disadvantages of certain alternatives need to be traded off. The complex dependencies and the amount of information that has to be processed in most
4.5 Summary and Conclusions
cases require aided decision making. Multicriteria decision making (MCDM) that helps to aggregate and weigh information is one method of choice. However, to determine weighting factors for decision categories as well as suitable levels of aggregation in order to safeguard a comprehensible and at the same time differentiated decision is challenging. To assess discrete alternatives methods of multiattributive decision making (MADM) like multiattributive value theory (MAVT) (see [81]), multiattributive utility theory (MAUT) (see [82]) or so-called outranking methods that compare alternatives pair wise are suitable. To visualize results of MCDM spider web diagrams (see, e.g., [39]) have proven one’s worth. For further reading concerning MCDM methods we refer to [83]. Although a broad methodological toolset exists for single aspects of logistic chains planning and assessment, a complete coverage of all aspects in a single and integrated framework is – so far – missing.
4.5 Summary and Conclusions
The development of industrial valorization chains for renewable raw materials mainly aims to substitute fossil raw materials, contribute to reduction targets of greenhouse gas emissions, and reduce the dependency on fossil resources. Process chains already established or in development compete for renewable raw materials, acreage as well as against existing or new products. To ensure profitability and ecological benefits of these process chains the efficiency of the technical conversion process and the logistical system are preconditions and have to be regarded in an integrated way. This requires an adequate consideration of the particularities of renewable raw materials. The yields of wood and agricultural crops depend especially on natural factors, the raw materials themselves and the involved actors and stakeholders. The raw materials have to be suitable for the technical conversion process and adapted to the natural environment they are cultivated and harvested in. In order to mobilize the amounts needed and to build-up and maintain efficient and reliable feedstock supply communication and interaction with the different actors and stakeholders needs to be based on reliability and trust. An optimal configuration of processing steps and machines depends on the specific circumstances to a large extent. Thereby, the design of the conversion process and especially its capacity has to be considered right from the design of renewable raw material-based logistics chains. This is because specific transportation costs increase with rising capacities whereas specific investments and operation costs decrease. Approaches aiming at a spatial and/or temporal decoupling of process chains try to combine the advantages of smaller plants and larger plants in one concept. Facility location planning is an important issue too. Large amounts of materials have to be transported and through economies of scale production costs may be reduced. Hence, to select a suitable location is of central relevance for process chains. Right from the design of renewable raw material-based logistics chains competition with fossil-based
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logistics chains and further valorization pathways for renewable raw materials need to be considered. Therefore to identify the most promising ones and to guide research and development toward efficient and competitive processes it is necessary to assess and compare utilization pathways at an early stage of the process development completely, from a technological as well as from a logistical point of view of the whole value chain. For this purpose a variety of assessment methods is available. However, deficits exist concerning a common and integrated assessment approach.
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5 Existing Value Chains Christoph Syldatk, Georg Schaub, Ines Schulze, Dorothea Ernst, and Anke Neumann
5.1 Industrial Biotechnology Today – Main Products, Substrates, and Raw Materials
Industrial biotechnology including fermentation and biotransformation processes is used to produce a wide range of bulk and fine chemicals like ethanol, lactic acid, citric acid, amino acids, biopolymers, secondary metabolites, and vitamins for many years. As a very important part, the fermentation technology makes use of various microorganisms (bacteria, yeasts, fungi, and very recently of algae) to convert mostly carbohydrate-based substrates and raw materials to products for an application in the chemical, food-, feed-, and pharmaceutical industry [1]. By simple use of a microbial production organism, a substrate or even a complex raw material can be directly converted to a wide range of specific products, ranging from compounds with a chemical structure that is very close to the raw material (e.g., production of gluconic acid from glucose) to products that seem to have virtually nothing in common with the starting material (e.g., production of β-lactam antibiotics and vitamins from sugars). A fermentation process can even replace a whole cascade of chemical reactions in comparison with a multistep industrial chemical process. Introducing biotechnological process steps into chemical syntheses often results in significant ecological advantages such as considerably reduced waste generation, reduced energy requirement, decreased use of solvents, elimination of dangerous intermediate products, etc. [1]. Table 5.1 gives a survey on the most important fermentation products worldwide produced in an amount of >500 t per annum, which may be of interest as building blocks for the chemical industry and their estimated world market prices [2, 3]. Having a look at the existing value chain of industrial biotechnology, all fermentation processes which have been commercialized in the last decades for the production of one of the building blocks mentioned in Table 5.1 presently rely on carbohydrates as feedstock. These feedstocks have to be considered as “intermediates” instead of “raw materials” according to Kircher [4] (see Figure 5.1). Moreover, the majority of fermentation processes, which recently are in the feasibility stage, also start from these feedstocks at the moment [2]. Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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5 Existing Value Chains Table 5.1 Estimated annual world production and estimated prices for microbial products useful as building blocks in chemical industry (based on Patel et al.[2] and DECHEMA [3]).
Microbial product
World production (t/year)
World market price (estimated in ¤/kg)
Area of application
Bioethanol
50 mio.
0.40
Biofuel, organic solvent
l-Glutamic acid
1.5 mio.
0.80
Food industry
Citric acid
1.5 mio.
1.00
Food and detergent industry
l-Lysine
700 000
1.60
Animal feed
Lactic acid
250 000
1.80
Food and textile industry
Acetic acid
190 000
0.50
Food and cleaning industry
Gluconic acid
100 000
2.80
Food, textile, building, and construction industry
Vitamin C
95 000
8
Food and pharmaceutical industry
l-Threonine
55 000
4
Animal feed
Xanthane
50 000
8
Food industry
Itaconic acid
15 000
6.50
Plastics and paper industry
l-Phenylalanine
15 000
8
Food and pharmaceutical industry
l-Tryptophane
1500
16
Food, feed, and pharmaceutical industry
l-Arginine
1000
16
Cosmetics and pharmaceutical industry
l-Cysteine
500
20
Pharmaceutical industry
The main substrates used in industrial microbiology today are glucose, sucrose, starch, glycerol, or acetate. Additionally, waste substrates as sugarcane and sugar beet molasses, corn steep liquor, deproteinized whey, or waste streams from food and paper industries are used very often as medium components. In some cases, complex vitamin and amino acid rich medium components like yeast extract, malt extract, or peptones have to be added to the media for optimal microbial growth and product formation. For the production of more complex compounds like antibiotics, chemical precursors have to be added sometimes. All fermentation processes mentioned in Table 5.1 have been optimized concerning their medium composition and substrates for many years and at the moment no better substrates will be available according to microbial growth, production yields, and raw material prices. While the number of big-scale industrial fermentation processes in a scale of >500 t per annum is limited to less than 20 at the moment, one of the main future
5.2 White Biotechnology – Future Products from Today’s Raw Materials? Raw Materials
Intermediates
Industrial and consumer products Consumer product Drugs
Functionality
Industrial product
Component Intermediate Amino acid
Feedstock
Single cell oil Acrylic acid
Polyacrylic acid
Enantiopure amino acids
Cuisine
Food Textiles Packaging Plastics
Polylactic acid
Lactic acid
Biomass
Ethanol
Sugar Sugar cane Sugar beet
Feed supplements
Enantiopure alcohols
Fuel
Glucose syrup Starch
Corn Seed
Bulk
Value
Figure 5.1 The existing value chain of industrial microbiology (based on Kircher [4]).
challenges will be the substitution of petroleum-based chemicals by renewable resources. For the production of chemicals from nonpetroleum-based raw materials, there is a choice between the development of a chemical process, for example, starting from renewable resources as raw materials (see Figure 5.2) or the development of a microbial fermentation process (see Figure 5.3). According to Kerton [5], a typical chemical industrial process to produce a chemical product or target molecule is typically developed in five parts: after decision on the starting materials and feedstocks, reaction types, reagents, solvents, and reaction conditions will be chosen. In most cases, it will be necessary to use a cascade of chemical reactions to produce the target molecule. This is different to the development of a chemical process: according to Patel et al. [2], a production organism has to be chosen and a suitable substrate or raw material. After conditioning of the raw material or substrate mostly by its conversion to fermentable sugars and optimization of the fermentation process, fermentation and product formation are done in a bioreactor, subsequently followed by separation and purification of the product. In both cases the use of by- and waste product and process integration into the overall facility concept and design are the follow-up steps.
5.2 White Biotechnology – Future Products from Today’s Raw Materials?
The NREL as well the European Union did extensive research studies on the substitution of petroleum-based chemical processes to produce bulk chemicals
97
98
5 Existing Value Chains Chemical product and target molecule?
Starting materials and feedstock?
Reaction types?
Reagents and catalysts?
Solvents and reaction conditions?
Chemical reaction and reactor selection
Separation and purification of the product
Disposal and/or reuse of waste and by products
Integration into overall facility concept and plant design Figure 5.2 Steps in the development of a chemical industrial process (based on Kerton [5]).
and intermediates for the chemical industry by processes based on renewable resources [2, 6]. In case of NREL, 33 six-carbon-atoms containing compounds were identified, most of them available by microbial fermentation processes from carbohydrates, while in case of the EU BREW project 13 key components were identified [7] (see Table 5.2), eight of them mainly produced by microbial fermentation at the moment. According to Patel et al. [2], these selected building blocks can be distinguished according to the prevailing strategy for their market entry (termed “strategic fit criteria” by Werpy and Petersen [6]) by four strategies, the first two of which play a key role in decision making [6]: 1)
Direct substitution of a bulk petrochemical. This strategy implies that a bulk chemical, which is presently produced from petrochemical resources, would be substituted by an identical substance, produced from biomass with the help of biotechnology. The substitute could either be the building block itself or a derivative of the building block. Advantages of this strategy will be that the markets for these products already exist and the market drivers are well known, which substantially reduces the uncertainty.
2)
Functional competition of biobased bulk chemicals with fossil-based ones. When making the transition from petrochemical to biobased produc-
5.2 White Biotechnology – Future Products from Today’s Raw Materials? Microbial product and target molecule?
Choice of raw materials and/or substrates
Choice of production organism
Conditioning of substrate and preparation of media
Strain optimization and up-stream processing
Fermentation and product formation
Separation of microbial cells and culture broth
Separation and purification of the product
Use of waste and by products
Integration into overall facility concept and plant design Figure 5.3 Steps in the development of a microbial industrial process (based on Patel
et al. [2]).
Table 5.2 The 13 key plant “carbohydrate-derived” building blocks identified in the EU “BREW” project (based on Patel et al. [2]).
Acetic acida) Acetone Butanol Citric acida) Ethanola)
Fumaric acid Glutamic acida) Gluconic acida) Itaconic acida) Lactic acida)
Malic acid Propionic acid Succinic acida)
a) Mainly produced by microbial fermentation at the moment.
tion, it will not always be necessary or possible to provide the same product. Rather, a comparable or even superior functionality could be provided. In this case, cost-competition with petrochemicals will become less important if a new or improved functionality can be provided which either allows the competition with established, proven products, or the opening of new applications. Within this strategy, two substrategies can be distinguished, as follows.
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5 Existing Value Chains
3)
Proven product. The substitute could be a proven product. This substrategy partly overlaps with the strategy “direct substitution of a bulk petrochemical,” but differs from it as it often also allows new or broader uses of the proven product. As the product is already proven, the market risks are reduced.
4)
New product. The substitute could be a new product. Examples are new polymers based on succinic acid as building block instead of fossil-derived dicarboxylic acids. Advantages are new market opportunities and no direct competition from petrochemical routes. Drawbacks lie in the not-yet-defined market and the requirements of substantial amounts of capital and time to develop it.
Several chemical routes are proposed in both studies to produce key intermediates for the chemical industry from the compounds mentioned in Table 5.2 [2, 6], but to meet the future demand of the chemical industry for these compounds, it will be necessary to produce them in comparable amounts and in the same price range as the petroleum-based compounds. For orientation, the estimated world production figures and indicative world market prices of a number of petrochemical and renewable raw materials for 2007 are given in Table 5.3. The world market prices for the petroleum- and biobased components are in the same range for raw materials and intermediates, but when using the biobased compounds for production of the petroleum-based intermediates, they will face the disadvantage to have to compete on a cost basis against processes which have been optimized for a long time, and which often run on depreciated capital. Further it becomes obvious that the amount of the recently available biobased materials will not be sufficient to meet the demands of biofuel production and the chemical industry. Additionally most of the biobased substrates recently used as substrates for microbial fermentations are in competition with food and feed and may not be used in big scale in future for the production of biofuels and chemicals.
5.3 Effects of Feedstock and Process Technology on the Production Cost of Chemicals 5.3.1 Introduction
Whenever a chemical product can be made via different routes, using different feedstocks (or raw materials), there will be economic criteria for selecting the most attractive route. One way to assess the economic attractivity of a production route is to compare the production cost. The most important contributions to production cost are indicated in Figure 5.4, that is, feedstock costs and cost related to the conversion process, subdivided into different contributions, for example, capitalrelated and operation-related [11].
5.3 Effects of Feedstock and Process Technology on the Production Cost of Chemicals Table 5.3 Estimated world production rate and world market prices in 2007 for fossil and renewable feedstocks and intermediates useful as building blocks in the chemical industry (data according to [8], DECHEMA, 2010 [3], OECD/IEA [9], and BP [10]).
Feedstock or intermediate
Estimated world production rate (in millions of tons per year)
Indicative world market price (in ¤ per ton in 2007)
Petrochemical raw materials and intermediates: Coal
4700
40 a)
3900
300
Ethylene
85
900
Propylene
45
850
Benzene
23
800
Caprolactam
4
2000
Isopropanol
2
1000
Petroleum
Renewable feedstocks and intermediates: Lignocellulose (from roundwood production and processing)
500b)
40
Cellulose (refined)
320
500
Sugar
140
250
Starch
55
250
Ethanol
50
400
Glucose
30
300
Glutamic acid
1.5
800
Lactic acid
0.25
1800
Acetic acid
0.19
500
a) Only 10% are estimated to be generally available for the production of chemicals. b) Only 10–25% are expected by the OECD to be generally available for bioenergy and chemical production.
During the history of industrial chemistry, there have been numerous examples where, for a given product, feedstock and/or process technology changed due to changing boundary conditions (availability of feedstock, innovative process technology, etc.). One historical example is the production of synthesis gas and subsequent methanol production in the 1970s [12] and more recent developments [13]. With cheap petroleum and later natural gas as feedstocks, steam reforming/partial oxidation had become the preferred processes to be used. With increasing oil price, however, coal gasification became more attractive in some
101
102
5 Existing Value Chains chemical product
feedstock raw material
production process
feedstock cost
production cost cost related to - capital - utilities, supplies, waste streams - labor - maintenance
Figure 5.4 General process and cost scheme for the production of a chemical product, with different feedstock and/or process technology alternatives.
locations. These changes can be understood in terms of feedstock and process technology effects on the production cost of chemicals. Cost-estimation procedures were reported in the literature and applied to the particular case, as for example by Schulze [12]. Today, with increasing price of petrochemical feedstocks and new processes being developed, alternative production routes using biomass feedstocks are gaining more attention. Therefore, this chapter presents a simplified costestimation procedure for looking at biomass-based production processes, to be compared to present petrochemical production routes. The procedure is based on specific investment and product yield figures. 5.3.2 Simplified Procedure for Cost Estimation
The specific production cost estimation method presented considers a steadystate situation for cash flow. Time value of money is neither considered nor the fact that costs may vary significantly during the lifetime of the industrial project. Table 5.4 outlines the procedure for estimating production cost, for comparing feedstock, and process investment effects. In cases where no detailed information of operating cost is available, a rough estimate of 20% of capital investment per year is assumed for the total of capital-related cost, maintenance, labor, and utilities. The effect of feedstock cost on production cost can then be presented in a diagram as shown in Figure 5.5, for different example cases that represent (i) high and low specific investment, and (ii) high and low selectivity (or product yield) situations. The slope of the straight lines in each case represents the reciprocal value of product yield, and the intercept represents the production cost per mass of product without feedstock costs (i.e., including all cost contributions outlined in Figure 5.4 with the exception of feedstock cost). Characteristic parameter values for all cases shown in Figure 5.4 are listed in Table 5.5. Production cost is calculated with Eq. (5.1), and the range of feedstock
5.3 Effects of Feedstock and Process Technology on the Production Cost of Chemicals Table 5.4 Definitions and assumptions used in production cost estimate, for comparing feedstock and process investment effects.
Basis: steady-state situation of cash flow with constant time value of money Intercept (€/kg):
annual operating cost ( w o feedstock ) annual mass of product
Annual operating cost (w/o feedstock): 20% of capital investment/year Incl. capital cost maintenance labor utilities Slope: 1/product yield Product yield:
mass of product mass of feedstock
Data source (investment, product yield): published data or own estimate
Table 5.5 Parameter values for different cases in Figure 5.5.
Case I
a b a b
Case II
Specific investment ¤/kg per year
Product yield kg per kg
Intercept ¤/kg
Slope kg per kg
1 1 3 3
0.9 0.5 0.9 0.5
0.2 0.2 0.6 0.6
1.1 2 1.1 2
production cost (Euro/kg)
2.5
case I b case II a
2 case II b
case I a
1.5 equity
1 0.5 0
0
0.5 1 feedstock cost (Euro/kg)
1.5
Figure 5.5 Effect of feedstock cost on production cost of chemicals; characteristic param-
eters, see Table 5.5; definitions and assumptions, see Table 5.4; examples, see text.
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5 Existing Value Chains
cost indicated in Figure 5.5 includes typical values of raw materials and commodity chemicals. Total production cost = spec. investment × 0.2 + feedstock cost ×
1 product yield
(5.1)
5.3.3 Example: Alkenes from Petroleum Fractions and from Bioethanol
The method outlined in Section 5.3.2 is used in the following to assess the economic perspective for producing low-boiling alkenes from bioethanol instead of from petroleum fractions. Biomass-based ethanol can be used in this way as raw material for chemical products, especially to produce polymers. The current world production of ethene and propene is mainly covered by the petrochemical route based on steam cracking, that is, thermal pyrolysis of petroleum liquids (naphtha, gas oils) and natural gas condensates, that is, ethane, propane, etc. [13–15]. A schematic stoichiometry is given in Eq. (5.2). As an alternative, ethanol can be converted via catalytic dehydration to ethene, as shown in Eq. (5.3) [16]. For steam cracking of naphtha, the reaction stoichiometry gives a maximum product yield of nearly 100 wt.%, whereas ethanol conversion can lead only to maximum yields of 61 wt.%. Due to very large production capacities, naphtha steam cracking units have relatively low specific investment (e.g., 500 Mio € for 500 000 t/year capacity [15]). The resulting production cost, therefore, is close to case I a in Figure 5.5. Accordingly, for an assumed feedstock cost of 0.5 €/kg, the resulting production cost of alkenes would be about 0.78 €/kg. If the feedstock cost is doubled to 1 €/kg, the resulting production cost would increase to 1.3 €/kg. Assuming the latter value for ethanolbased alkenes (and the same investment for ethanol dehydration), a maximum allowable ethanol cost would be about 0.5 €/kg (for being competitive with naphtha steam cracking). The procedure outlined should be helpful for identifying advantageous situations to replace naphtha steam cracking by dehydration of bioethanol, as well as to any feedstock and process technology by other feedstocks/process technologies. It was applied for a comparison of different biofuels in a recent overview of synthetic hydrocarbon fuels from lignocellulosic biomass [17]. If more detailed investment and operating cost figures are available, the resulting production cost estimates become more accurate. Steam cracking of naphtha C6H14 → 3 C2H4 + H2 → 2 C3H6 + H2
stochiometric product yield: 0.98 kg/kg
(5.2)
Dehydration of ethanol C2H5OH → C2H4 + H2O stochiometric product yield: 0.61 kg/kg
(5.3)
5.4 New Raw Materials for White Biotechnology
5.4 New Raw Materials for White Biotechnology
As discussed in Section 5.2 and shown in Table 5.3, the common substrates used in industrial microbiology will be sufficient for today’s industrial microbial production processes, but will be far away from meeting the demands for the production of biofuels and bulk chemicals in future. Further on, it will be necessary to use mainly only those substrates which will not be in competition with food or animal feed. Therefore several alternative raw materials substrates have already been discussed in literature, for example, related to selected seeds, to biomass, or to biomass-related industrial by-product and waste streams. According to Busch et al. [18], agriculture currently generates large quantities of residues and by-products in Europe, which have only to be added to the value chain shown in Figure 5.1 at a lower level. These residual substances include, for example, whey, molasses, potato proteins, and loppings, which in turn contain a variety of compounds, which could form an inexpensive basis for new, premium products, for example, in the pharmaceutical, food, feed, and cosmetics industries. According to Soetaert and Vandamme [1], the following industrial sectors supply the most important renewable raw materials: (i) the sugar and starch sector – it produces carbohydrates such as sugar, glucose, starch, and molasses from plant raw materials such as sugar beet, sugarcane, wheat, corn, potatoes, sweet cassava, rice, etc.; (ii) the oil and fat processing sector – it produces numerous oleo-chemical intermediates such as triglycerides, fatty acids, fatty alcohols, and glycerol from plant raw materials like rape seeds, soybeans, palm oil, coconuts, and animal fats; and (ii) the wood processing sector, particularly the cellulose and paper industry – it produces mainly cellulose, paper, and lignins from wood. Due to strongly increasing production of biodiesel for fuel use in the coming years, its by-product glycerol will become available in large amounts at low price. Within a strategy of glycerol valorization, it could also be used as carbon and energy source in fermentative processes [2]. As an example for the wide range of raw materials and substrates which could be used in white biotechnology, Table 5.6 gives a detailed survey on so-called second-generation feedstocks as the possible raw material for bioethanol production [19]. Most of these compounds could also be useful as substrates for microbial fermentation to produce the intermediates mentioned in Table 5.2. Most of the raw materials in Table 5.6 are related to plant biomass, and a range of different technologies will have to be used to industrially convert the available biomass sources into energy carriers or intermediates for chemical industry, which will lead to additional costs: (i) fractionation technology primarily based on physical and chemical separation methods to separate the agricultural raw materials into their separate components and (ii) enzymatic technology mainly using a combination of hydrolytic enzymes including starch and cellulose degrading enzymes. Comparing prices for lignocellulose and cellulose, a distinct increase in costs becomes obvious, although the price for refined cellulose is already in the range of petrochemicals used in the chemical industry (see Table 5.3).
105
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5 Existing Value Chains Table 5.6 Second-generation feedstocks as possible raw material for the production of bulk
chemicals and bioethanol (based on Antzar-Ladislao, Turrion-Gomez [19]). Energy crops
Agricultural and wood residues
Organic waste
Traditional breeding
Vegetable oils
Amaranth
Barn
Animal fat
Miscanthus
Calophyllum inophyllum
Bamboo
Citrus waste
Food waste
Switch grass
Corn oil
Energy maize
Corn stover
Municipal solid waste
Willow
Castor bean
Eucalyptus
Green waste
Olive pulp
Cotton seed
Grass
Industrial waste
Recycled cooking oil
Jatropha
Miscanthus
Sugarcane bagasse
Wastewater from pulp and paper industry
Palm
Rape seed oil
Sawdust
Wastewater from tofu or sugar factories, etc.
Pogamia pinnata
Poplar
Wheat straw
Soybean
Salix
Waste ricestraw
Sunflower
Sugar beet
Wood
Sweet sorghum Switch grass Willow
Table 5.7 Availability of biomass – estimated biomass potential in the EU in millions of tons/ year (based on [7]).
Year
2010
2020
2030
Organic waste Energy crops Forest products Total
100 43–46 43 186
100 76–94 39–45 215–239
102 102–142 39–72 243–316
A very important question will be the availability of biomass. Table 5.7 shows the estimated biomass potential in the EU in millions of tons for 2010–2030 [7]. As a conclusion from these data, in the EU biomass raw materials will not be sufficient to meet at the same time the demand for energy carrier- and bulk chemical production. What could be the alternatives?
5.5 Case Studies: Lignocellulose as Raw Material and Intermediates
Although white biotechnology in general does not require feedstocks from genetically modified plants (GMPs), synergies between white and green biotechnologies are discussed to deliver feedstocks which allow a more cost-effective production of biobased chemicals [2]. The development of so-called “energy plants,” optimal for the production of biofuels and chemicals by common breeding methods, will take at least one decade. Therefore extensive research and development on GMP with altered agronomic properties, for example, resulting in increased yield or reduced need for pesticides, irrigation, or fertilizer as well as on GMP with biomass tailored in such a way that it is more amenable to conversion to fermentable sugars is done in the United States. In Europe, presently, it is a controversial issue what the role of green biotechnology and its interplay with white biotechnology could and should be. Another interesting alternative in future, already under investigation, could be a high cell density cultivation and use of microalgae biomass having a much lower content of lignin in comparison to the plant materials mentioned in Table 5.6. In Sections 5.5 and 5.6, two case studies will be discussed in more detail for the use of lignocellulose and single-cell oil (SCO) as starting materials for the production of intermediates for the chemical industry.
5.5 Case Studies: Lignocellulose as Raw Material and Intermediates 5.5.1 Bioethanol and Chemical Production from Lignocellulosic Biomass
Lignocellulosic biomass is mainly constituted of cellulose, hemicellulose, and lignin and is available in various forms. In future, lignocellulose-containing substrates will be an interesting option for the production of ethanol and other chemicals. Energy sources obtained from lignocellulosic sources belong to the so-called second generation of biofuels. In contrast to first-generation biofuels as biodiesel from rape seed oil or ethanol from sugarcane or wheat, secondgeneration biofuels will not be in direct competition with the production of food or animal feed. Possible sources for lignocellulosic feedstocks (Table 5.8) can be, for example, wood residues, agricultural wastes, fast-growing energy crops like switch grass with high yields per hectare, or even municipal solid wastes. The so-called biorefineries should not only be able to produce biofuels but a broad range of products useful as precursors for bulk and fine chemicals and new industrial polymers. Currently, bioethanol is the main product produced from lignocellulosic feedstock. The process of bioethanol production from lignocellulose is currently tested in pilot plants in different countries all over the world, and according to Tan et al. [23] it is consisting of the following steps as discussed next (see Figure 5.6). A physical, chemical, or biological pretreatment will break down the lignocellulosic network and make the substrate better available for enzymatic hydrolysis.
107
Miscanthus (Miscanthus sinensis), switchgrass (Panicum virgatum), reed canary grass (Phalaris arundinacea), other grasses
Perennial cultivation
Straw, stover
Treetops, branches, stumps
Agriculture
Forestry and logging
Primary residues
Poplar (Populus spp.), willow (Salix spp.), eucalyptus (Eucalyptus spp.), locust (Robinia spp.)
Short-rotation coppice
Dedicated energy crops
Source of lignocellulosic raw material
Relatively cheap; no additional land required; removal can help to prevent forest-fires
No competition with food; no additional land required; collection can prevent pests; existing pasture machinery
Can be grown on degraded land; can mitigate soil erosion; can increase soil carbon and soil fertility in poor soils; existing pasture machinery
Relatively fast growing; can reduce soil erosion; can increase soil carbon and soil fertility in poor soils; available all year round
Potential advantages
Other uses: fuel wood demand, heat/ electricity production; removal can cause loss of organic matter, soil carbon and reductions in habitat for biodiversity; not suitable for long transportation distances
Other uses well established, e.g., nutrient cycling, animal feed, heating; low energy density; available only during crop harvesting season
Potentially invasive; usually planted on arable land; relatively low energy density; available during harvest in autumn and winter
Potentially invasive; usually planted on arable land; relatively low energy density; specialist machines needed to harvest or labor-intensive manual harvesting
Constraints
Table 5.8 Possible sources for lignocellulosic feedstock with technical requirements, potential advantages, constraints, and availability (modified according to [9], based on [20–22]).
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5 Existing Value Chains
Canola, oil palm, jatropha, rapeseed (presscake, shells, fruit bunch)
Sawdust, bark
Vegetable oil production
Forestry processing
Municipal solid waste
Palettes, furniture, demolition timber
Sugarcane, sweet sorghum, sugar beet (begasse, pulb)
Sugar and firstgeneration bioethanol production
Tertiary residues
Coffee, rice, corn, cacao (shells, husks, cob)
Crop processing
Secondary residues
Source of lignocellulosic raw material
Competition with heat and electricity generation
Competition with heat and electricity generation
Concentrated at saw and paper mills; no additional land required; avoids disposal costs; year round availability; relatively high energy density
Concentrated at landfill site; no additional land required; avoids disposal costs; separation from other waste might be required; year round available
Competition with heat and electricity generation; press cake provides a valuable animal fodder; available during crop harvesting season
Competition with heat and electricity generation; animal feed, available during feedstock harvesting season
Competition with heat and electricity generation
Constraints
Concentrated at oil mills; currently very cheap; no additional land required; avoids disposal costs
No food competition; concentrated at ethanol plant; no additional land required; avoids disposal costs
Byproduct – no food competition; no additional land required; concentrated at processing site; avoids disposal costs; year round local availability
Potential advantages
5.5 Case Studies: Lignocellulose as Raw Material and Intermediates 109
110
5 Existing Value Chains
Lignocellulosic biomass
Enzyme
Pretreatment
Hydrolysis
Additional steps for ethanol production from lignocellulose
Glucose Yeast
Fermentation
CO2
Bioethanol Water Distillation
Water-free bioethanol
Figure 5.6 Bioethanol production from lignocellulosic biomass (according to Tan [23]).
The enzymatic hydrolysis will produce reducing sugars mostly by using enzymes of the aerobic fungus Trichoderma reesei (cellulases and hemicellulases). In a subsequent fermentation step, the reducing sugar will be converted into ethanol by yeasts, recombinant bacteria, or fungi. For the use as a fuel, water-free ethanol will be obtained by distillation with subsequent dehydration. As the central intermediate of this process is glucose, this scheme also applies for all other basic (platform) chemicals, which can be obtained by fermentation of glucose with any fungi, yeast, or bacteria. For process economies, it is recently discussed to combine, for example, hydrolysis and fermentation in the same step as so-called simultaneous saccharification and fermentation (SSF). 5.5.2 Limitations 5.5.2.1 Substrate From the above described current state of the production of bioethanol (or any other platform chemical) from lignocellulose, the following limitations can be identified. The substrate costs have a decisive influence on the final liter price of the ethanol; these must be kept as low as possible in order to be able to compete with other fuels. However, as the price of the raw materials is dependent on supply and demand, they are difficult to either predict or control. Additionally, on account of its complex structure lignocellulose is not easily broken down by enzymes. 5.5.2.2 Pretreatment Cellulose and hemicellulose form a complex network that is additionally protected against enzymatic degradation through the presence of lignin in the cell wall. Consequently, yields from enzymatic degradation are still low. An expensive pretreatment process, during which a significant amount of the biomass is currently either lost or degraded, is necessary to facilitate enzymatic lignocellulose degrada-
5.5 Case Studies: Lignocellulose as Raw Material and Intermediates Table 5.9 Composition of selected plant biomass (based on [25]).
Content of compound (%)
Agricultural waste
Woody plants
Municipal solid waste
Herbaceous energy crops
Cellulose Hemicellulose Lignin Other carbohydrates Protein Ash Other
43 27 17 NSa) NS NS 13
45 25 22 NS NS 3 5
45 9 10 9 3 NS 9
45 30 15 NS NS NS 10
a) Not specified.
tion. In respect of the pretreatment, one must ensure that the formation of sugars during the following hydrolysis is improved while at the same time avoiding as far as possible the formation of toxic or inhibitory substances which could negatively influence the fermentation [24]. Additionally, the loss of sugars, for example, via their degradation should be kept to a minimum. Equally the use of energy and expensive chemicals should be kept to a minimum in order to keep the costs as low as possible [25]. Pretreatment is in principle possible through physical, physical–chemical, chemical, and biological methods [26]. 5.5.2.3 Composition of Biomass Further, the composition of the substrates, that is, the relative percentages of the three main components, plays an important role in the breakdown of the lignocellulose. Table 5.9 provides an overview of the composition of the four main groups of lignocellulosic biomass. In particular, the lignin component varies greatly; namely, lignin-poor raw materials, for example, herbaceous materials are easier to degrade than lignin-rich raw materials, for example, hard- and softwoods. 5.5.2.4 Hydrolysis Following the pretreatment, a solid–liquid separation is generally carried out. The solid phase containing lignin and cellulose is subjected to hydrolysis, while the liquid phase, which contains the released sugars such as xylose, is processed separately. Depending on the specific process, it can be subject to a pentose fermentation or the further processing to by-products such as animal fodder. Hydrolysis can in principle be carried out with dilute or concentrate acids, or with the aid of enzymes, whereby most recent research interest has focused on enzymatic starch liquidation. Owing to the milder reaction conditions of pH 4.8 and a temperature range of 45–50 °C, enzymatic hydrolysis is more cost-efficient than the use of acid and, further, less materials are formed which could have a potentially negative effect on the fermentation microorganisms [27]. During enzymatic hydrolysis, nonproductive cellulose–lignin bonding limits the conversion via the enzyme. Should an enzyme adsorb onto lignin, it is irreversibly
111
112
5 Existing Value Chains
bound and is so no longer available for cellulose conversion, resulting in an increase in the amount of enzyme required and so higher costs. Enzyme costs cannot as yet be firmly set for commercial processes, as large purchasers do not exist and also the enzyme producers must further optimize their production processes. 5.5.2.5 Fermentation The fermentation to ethanol could, until now, only be satisfactorily undertaken with C6 sugars, such as glucose, where whole microorganisms – principally Saccharomyces cerevisiae – are used. A large percentage of lignocellulosic biomass, however, is composed of the C5 sugars in hemicellulose, for example, xylose, arabinose, etc., which remain barely exploited for alcohol production. Rather, this pentose component is often sold cheaply as feed additive for animals. In addition to the limited substrate exploitation, the poor ethanol tolerance of the fermentation species presents a further problem. If the ethanol in the fermentation broth reaches a specific concentration, it inhibits the microorganisms, and so stops further glucose conversion and ultimately leads to cell collapse on account of the high ethanol concentration. The limitations and problems of the ethanol process are so diverse that there is not one big solution to enable an economically viable process but detailed optimization of every step of the process. 5.5.3 Research and Development Potential
In addition to improved biomass pretreatment methods to increase the yield from enzymatic hydrolysis, new crops are also being investigated which either through breeding or genetic manipulation demonstrate, for example, a higher yield per hectare, a reduced lignin content, or in comparison with hemicellulose a greater cellulose content. In the future hydrolysis, inhibitors should either be avoidable via gentler pretreatment processes or separated as much as possible via detoxification prior to the hydrolysis. The hydrolysis itself must be made more cost-effective through more efficient enzymes. To this end, screening or protein engineering steps must be carried out and new, cheaper industrial scale production processes for enzymes need to be developed. The inactivation of the enzyme on lignin can be avoided through alternative processing steps, for example, elimination of the lignins before addition of the enzyme or through new additions to the hydrolysis in the form of surface active agents, proteins, or solvents. Finally there are research approaches that could enable a higher ethanol yield to be achieved; the use of alternative microbial strains is here just as valid an approach as the optimizing of existing through metabolic engineering. Also the use of mixed cultures, that is, two different species used together in fermentation can increase the resultant ethanol output. In addition to varying and optimizing the microorganism used, process management plays an important role in the ethanol yield. In this context it is possible via vacuum fermentation, in-situ-product-removal (ISPR), or integrated process management, to keep the
5.5 Case Studies: Lignocellulose as Raw Material and Intermediates Table 5.10 Limitations and R&D potential in producing bioethanol from lignocellulose.
Limitation Substrate
I. II.
III. Enzymatic hydrolysis
Ethanol formation
Substrate costs Substrate availability from cellulose, hemicelluloses, and lignin Substrate composition
I. Enzyme costs II. Enzyme inactivation through binding on lignin
I.
Use of C5 sugars
II.
Product inhibition
Research and development potential
• •
Improvement of the pretreatments
•
Formation of inhibitors avoiding/ improved detoxification processes
•
Addition of auxiliary agents, e.g., surfactants, proteins, solvents to avoid lignin adsorption Improved enzyme properties via protein engineering and screening methods
•
Changes in the plant material (reduced lignin content or separation from the lignin)
•
Cheaper enzyme production through improved process controls (avoiding adsorption on lignin)
•
Use of alternative stains Metabolic engineering, or use of mixed cultures
•
Altered process controls (e.g., vacuum fermentation, in-situ product removal (ISPR), integrated processes such as SSF, SSCF, CBP)
ethanol concentration in the fermentation medium permanently low and so avoid a potential inhibition of the microorganisms. Table 5.10 summarizes the individual process limitations and the associated research and development potential. All considerations for the use of lignocelluloses for the production of bioethanol or other platform chemicals should include the overall mass and energy balance as well as the availability through the year and the transportation needed. Regarding a study of IEA/OECD 2010 [9], there is no additional land available in the short term and only 10% of global forestry and agricultural residues are assumed to be available for biofuel or platform chemical production. Therefore, there will always be a direct competition of bioethanol or other platform chemicals production with food production even if so-called plant waste material is used as the real limitation is the arable land available. In other words, as long as not real unused plant waste (the above mentioned 10%) is utilized, but “would be” plant waste like straw or energy plants, there will always be a direct competition to food as the real limitation is the arable land available. Therefore not only the process itself (from raw material to the product)
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but also the possible different use of the same land should be considered to get the most effective exploitation of all resources.
5.6 Case Studies: “SCOs” as Raw Material and Intermediate 5.6.1 Microbial SCOs
SCOs are triacylglycerols which are produced intracellularly by certain microorganisms, so-called oleaginous microorganisms as storage lipids. Those lipids contain a similar fatty acid composition as plant oils and could, therefore, be a suitable alternative as base material for industrial applications, as they do not compete with food and feed [28]. Yeasts, fungi, bacteria, and microalgae belong to the group of oleaginous microorganisms. They all share the special feature to have more than 20% lipids in their cellular dry weight. Whenever they are nitrogenlimited, the cell division is interrupted, but at a concurrent carbon excess, the carbon will be converted into SCOs as storage lipids. The amount of lipid can reach up to 70% of the cellular dry weight in several oleaginous microorganisms [29]. Depending on the chosen microorganism, different carbon and energy sources are required. CO2 and sunlight as zero-cost carbon sources for microalgae represent an advantage for photoautotrophic microalgae. In contrast, producing SCOs with heterotrophic microorganisms like yeasts, fungi, and bacteria require carbohydrate-rich substances as raw material. Usually glucose and sucrose are the substrate of choice as they are easily accessible from agricultural crops, but also waste substrates like whey from cheese industry is used. The main components of SCOs are saturated fatty acids including palmitic acid (16 : 0) and stearic acid (18 : 0), but they also contain high amounts of unsaturated fatty acids with carbon chain lengths of 16 and 18 (16 : 1, 18 : 1, 18 : 2, 18 : 3) (Table 5.11), there under especially polyunsaturated fatty acids (PUFAs) with high value for industrial applications [30, 31]. 5.6.2 Industrial Use of Microbial SCOs
SCOs are interesting intermediates for several industrial applications. Due to their chemical functionality available in their structure, they are excellent bioresources for the production of detergents, biopolymers, and other oleochemicals [32]. Because of their high amounts of polyunsaturated fatty acids, SCOs are suited for high-value products in the cosmetics, food, and pharmaceutical industry [33]. Gamma linolenic acid (GLA, 18 : 3(n−6)), for example, is an ω6 fatty acid with anticancerous and anti-inflammatory properties and can, therefore, be used as dietary supplement for treating problems with inflammation and autoimmune diseases.
5.6 Case Studies: “SCOs” as Raw Material and Intermediate Table 5.11 Lipid content and fatty acid composition of microbial single-cell oils and selected
plant oils. Max lipid content (% w/w)
Yeast Fungi Microalgae Bacteria Plant seed oils Palm oil Cottonseed oil Soybean oil Rapeseed oil
58–72 57–86 16–77 18–40
Major fatty acids (% w/w) 16 : 0
16 : 1
18 : 0
18 : 1
18 : 2
18 : 3
11–37 7–23 12–21 8–10
1–6 1–6 55–75 10–11
1–10 2–6 1–2 11–12
28–66 19–81 58–60 25–28
3–24 8–40 4–20 14–17
1–3 4–42 14–30 –
44 27 11 14
– – – –
39 18 22 56
11 51 53 26
Trace Trace 8 10
5 2 4 2
Another example is docosahexanoic acid (DHA), an ω3-fatty acid, which is found in fish oil and known to reduce the risk of heart diseases. Most of DHA in fish arises from photosynthetic and heterotrophic microalgae, which represents the start of the food chain. Therefore microalgae are suitable producer for such kinds of fatty acids. 5.6.3 Limitations and Research and Development Potential
Autotrophic microalgae as well as heterotrophic yeasts, bacteria, and fungi implicate limitations for a commercial SCOs production process. An overview is listed in Table 5.12. The main reasons are the costly downstream process of the SCOs and the high costs of carbon sources for heterotrophic microorganisms. The relation between the costs for carbon sources (1/4 of the product oil) and the stoichiometry of carbon to oil conversion is not efficient. Theoretical calculations reveal that 33 g oil can be achieved from 100 g glucose, excluding energy consumption for maintenance metabolism [29]. In principle, conversion from glucose to oil is only a conversion from one agricultural resource into another resource without an economic gain. This problem can be only overcome if carbon sources are less expensive or if the product “SCOs” is of higher value than usual commodity oils. Zero-cost or low-cost carbon sources like agricultural waste residues containing high amounts of cellulose and hemicellulose or raw glycerol, a by-product from biodiesel production, are alternatives for an economic production process of SCOs with heterotrophic microorganisms. However cellulose and hemicellulose would require a cost-effective prior hydrolysis step to convert it into usable sugars like glucose and xylose. Concerning agricultural waste like straw or food-processing waste, one has to consider that also such feedstock is not a zero-cost carbon source
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Stoichiometry of carbon to oil conversion (5 t glucose for 1 t oil and simultaneous only fourfold price for oil compared to sugar)
SCOs are intracellularly → expensive downstream process
Autotrophic and heterotrophic MOs
In open systems, algae production could not be stably maintained over a longer period of time
Limited face-area for microalgae and not sufficient (cheap) light sources
High investment costs for production facilities and energy demand for harvesting biomass of low concentration
Photobioreactors for algae are too expensive → production of SCO is not economic
Cell density of microalgae is low due to the low light penetration
Heterotrophic MOs
Autotrophic MOs
Limitations
Optimization of culture conditions Optimization of production process, i.e., with a sequential batch
Strain optimization
Improvement in oil extraction, separation, and purification; reduction of downstream processing steps
Production of high value SCOs like PUFAs
Cost-effective hydrolysis for hemicelluloses as carbon source
Classical screening of suitable/new oleaginous microorganisms able to convert low-cost carbon sources
Suitable low-cost carbon sources, agricultural/industrial waste material as carbon source hemicelluloses, C-5 sugars as carbon source
Development of suitable photobioreactors allowing penetration of light sources
Genetic modification of lower cost production systems
Research and development potential
Table 5.12 Potential of microbial single-cell oils (SCOs): limitations and demand for research and development.
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5.7 Conclusions
as they have to be collected, transported, and stored before they can be used. One further disadvantage of wastes from seasonable crops is the fact that they are not accessible throughout the year. A general problem of SCOs production by oleaginous yeast in a fermenter is the high volume of waste liquor to get rid of after the harvest of the cells [29]. Concerning microalgae, limited face-area (rather than volume-related reactors) and insufficient (cheap) light sources are known constraints for economic SCOs production. In addition, it is difficult to produce algae stably in open systems over a longer period of time. Both aspects necessitate the development of a suitable photo bioreactor allowing penetration of sufficient light sources and higher cell densities. The downstream process of intracellular SCOs is still too expensive because of high energy demand for harvesting biomass of low concentrated algal cells and the extraction of intracellular SCOs demands many process steps. Even though much research effort was put into the production of SCOs in the last 30 years, only six processes could be commercialized, including the production of cocao butter equivalent (CBE), GLA, DHA, and arachidonic acid (AA). However, each commercialization attempt failed because of lower cost alternatives on the market [28]. The answer to this problem is cost reduction via less- or zero-cost carbon sources, the attempt to produce high-value oils (e.g., PUFAs), and to reduce the energy consumption during downstream process. Besides the costs for the raw material, the downstream process including the extraction, separation, and purification of intracellular SCOs has to be optimized, for example, by reducing the process steps. Further solutions to optimize SCOs production are the following: screening of new suitable oleaginous microorganisms able to convert low-cost carbon sources into SCOs, strain optimization, optimization of cultivation conditions, and optimization of production process, for example, with a sequential batch.
5.7 Conclusions
In future, an increasing number of chemicals and materials are expected to be produced using microbial fermentation and/or enzyme technology in one of their processing steps. Replacing the existing “hydrocarbon economy” with a “carbohydrate” economy will not be easy or cheap. Nevertheless, there is a paradigm shift in the chemical industry at the moment from the conversion of hydrocarbons to the conversion of carbohydrates, requiring fundamentally different chemical reactions and processes [2]. For the production of most low-molecular-weight, watersoluble chemicals of industrial utility as intermediates in white biotechnology, microbial fermentation could become the preferred production platform in future, if it is possible to secrete them into the medium. There are number of advantages for microbial fermentation processes: (i) they can be used for producing existing
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products in a more efficient and sustainable way from renewable resources, (ii) they allow an increasing eco-efficient use of renewable resources as raw materials for the industry, and (iii) they will enable a range of industries to manufacture products in an economically and environmentally sustainable way [2]. Nevertheless, all commercialized processes for the production of microbial intermediates for the chemical industry still rely on glucose, sucrose, or starch as feedstocks, of which prices are in the range of petroleum-based intermediates and are too high. These feedstocks will not be able to meet the demand of the chemical industry in future and therefore to substitute the petrochemical compounds: the production of bulk chemicals differs in many challenging aspects from the existing biotechnological production of fine and specialty chemicals as availability of substrates and/or raw materials, long-running processes in comparison to chemical reactions, higher importance of process than product innovation, and competition against well-established, optimized chemical processes [2]. In spite of that, the main problem to be solved in future remains the sufficient supply of cheap substrates and raw materials for these processes. Biomass feedstocks not in competition with feed or food should be available at low costs and on a very large scale. The development of so-called energy plants optimal for the production of biofuels and chemicals by common breeding methods will take at least one decade. GMP could be an option, but in Europe, presently, green biotechnology is a controversial issue. The production of cellulosic crops, such as short rotation coppices, winter cover crops, or perennial grasses, could have substantially more positive environmental attributes than production of corn, soy, or other annual row crops [19]. The use of other biomass feedstocks, such as solid waste including green waste, food waste, and biodegradable fractions of municipal solid waste, will require a pretreatment in all cases. A high celldensity cultivation and use of microalgae biomass having a much lower content of lignin in comparison to the plant materials mentioned still requires a strong R&D input. Summarizing, the development of integrated concepts (agriculture, biology, chemistry, forest engineering, process engineering) will be essential for an economic production of chemicals from waste materials and green biomass in future, and will have to meet the demands of food, animal feed, and energy production at the same time. It is generally assumed that this will be a long-term development with gradual implementation until 2050 [2].
References 1 Soetaert, W. and Vandamme, E. (2006) Biotechnol. J., 1, 756–769. 2 Patel, M., Dornburg, V., Hermann, B., Roes, L., Hüsing, B., Overbeek, L., Terragni, F., and Recchia, E. (2006) BREW, final report: medium and long-term opportunities and risks of the
biotechnological production of bulk chemicals from renewable resources, http://www.chem.uu.nl/brew/ programme.html (accessed 12 July 2010). 3 DECHEMA (2010) Positionspapier: Rohstoffbasis im Wandel. http:// www.dechema.de/dechema_media/
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14 Zimmermann, H. (2009) Erdöl Erdgas Kohle, 12, 191–196. 15 Zimmermann, H. and Walzl, R. (2003) Ullmann’s Encyclopedia of Industrial Chemistry, 6th, Completely Revised Edition, vol. 12, Wiley-VCH Verlag GmbH, Weinheim, pp. 531–580. 16 Morschbacker, A. (2009) J. Macromol. Sci. Part C Polym. Rev., 49, 79–84. 17 Schaub, G. and Pabst, K. (2011) Synthetic hydrocarbon fuels from lignocellulosic biomass, in CarbonNeutral Fuels and Energy Carriers (eds N. Muradov and N. Veziroglu), Taylor & Francis, CRC Press, New York, to appear. 18 Busch, R., Hirth, T., Liese, A., Nordhoff, S., Pulds, J., Pulz, O., Sell, D., Syldatk, S.C., and Ulber, R. (2006) Biotechnol. J., 1, 770–776. 19 Antizar-Ladislao, B. and Turrion-Gomez, J.L. (2008) Biofuels Bioprod. Bioref., 2, 455–469. 20 El Bassam, N. (1998) Energy Plant Species – Their Use and Impact on Environment, James and James Science Publishers Ltd, London. 21 Faaij, A., van Doorn, J., Curvers, T., Waldheim, L., Olsson, E., van Wijk, A., and Daey-Ouwens, C. (1997) Biomass Bioenergy, 12, 225–240. 22 Rosillo-Calle, F., de Groot, P., Hemstock, S.L., and Woods, J. (2006) The Biomass Assessment Handbook: Bioenergy for A Sustainable Environment, Earthscan Publications Ltd, London. 23 Tan, K.T., Lee, K.T., and Mohamed, A.R. (2008) Energy Policy, 36, 3360–3365. 24 Sun, Y. and Cheng, J. (2002) Bioresour. Technol., 83, 1–11. 25 Wyman, C.E., Dale, B.E., Elander, R.T., Holtzapple, M., Ladisch, M.R., and Lee, Y.Y. (2005) Bioresour. Technol., 96, 1995–1966. 26 Sánchez, Ó.J. and Cardona, C.A. (2008) Bioresour. Technol., 99, 5270–5295. 27 Olsson, L. and Hahn-Hagerdal, B. (1996) Enzyme Microb. Technol., 18, 312–331. 28 Ratledge, C. and Cohen, Z. (2005) Single Cell Oils, AOCS Press, Champaign, IL. 29 Ratledge, C. and Cohen, Z. (2008) Lipid Technol., 20, 155–160.
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6 Future Biorefineries Abbas Kazmi and James Clark
6.1 Introduction
There have been significant advances in the implementation of the biorefinery concept over the past decade with the production of biofuels such as bioethanol and biodiesel from sugarcane, corn starch, and plant oils. This has set a firm foundation for biorefineries to expand into other applications such as the chemicals and fulfill the vision of integrated biorefineries. The fuels industry has faced significant challenges including the food versus fuel issue and a relatively low crude oil price in 2009; however, it seems that the industry is succeeding but future challenges remain such as battery powered cars which may pose a greater challenge. To prepare for such challenges, the biofuel industry must utilize all the agricultural by-products either to increase yields of fuel or manufacture specialty chemicals to make the industry more economically sound as shown in Figure 6.1. Biomass has been used as a source for chemicals for hundreds of years for applications such as natural pigments and pharmaceuticals. Although the concept of deriving chemicals from biomass is well known, the industry has developed and grown during the first half of the 20th century using relatively cheap crude petroleum as a feedstock. The petrochemical industry is one of the largest, if not the largest, economic sector in the world supplying raw materials for innumerable products which modern society is completely dependent on. The challenge for the biorefinery is to produce products with similar properties and they need to be derived from a biomass source. A company based in Norway called Borregaard is a good example of a biorefinery in practice. Their main site, based Sparsborg, uses wood as the feedstock to produce a diverse range of products such as energy and food ingredients. The company has developed many applications for lignosulfonates such as agricultural chemicals, battery expanders, carbon black dispersions, cement, ceramics, emulsions, fertilizers, humic acid, industrial binders, and micronutrients. Other commercial products include specialty cellulose, hydrochloric acid, amino alcohols, hydroquinone, omega oils, and pharmaceutical-grade bioethanol. Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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Figure 6.1 Feedstocks for the biofuel industry and associated side streams.
The technology used in the petrochemical industry is well defined; however due to the complexity of the biorefinery concept, a single technology will not provide a solution. With a wide variety of feedstocks and products, a number of key technologies will be required to separate and process raw materials. Clean separating techniques and reaction mediums such as supercritical CO2 will be required. The breakdown of biomass can be done in several ways such as enzymatic hydrolysis, acid hydrolysis, gasification, and pyrolysis, which will be discussed in more detail later.
6.2 Current and Future Outlook for Biofuels
The demand for biofuels is increasing as the supply of crude oil diminishes. The pollution generated from the conventional gasoline is far greater than that of bioderived fuels, and this is clearly observable when visiting Brazil, a pioneer in bioethanol production and infrastructure. As biofuels are renewable, the greenhouse gas emissions are significantly reduced compared to crude oil derived fuels. The volatility in the price of crude oil has become a problem for many countries and with the price set to rise over the years, many countries could shift to higher targets of biofuel blending.
6.2 Current and Future Outlook for Biofuels
6.2.1 Bioethanol
With Brazil and the USA taking the lead in the production of bioethanol, many other regions of the world are following in their footsteps. The Brazilian bioethanol industry is based on sugarcane and has proven to be very efficiently and economically robust, in particular due to the utilization of the bagasse to generate electricity, which is sufficient to run the mill and leave excess for export to the grid. Although currently the tops and leaves of the sugarcane are not utilized, they have much potential as a biorefinery feedstock. Interestingly, only 1% of the agricultural land in Brazil is used for sugarcane which supplies 50% of the countries fuel requirements. This indicates that Brazil could become a large exporter of bioethanol and also has the potential to establish a chemical industry based on sugar, ethanol, or other agricultural by-products. In the USA, the bioethanol industry is based on corn starch and has rapidly grown due to high crude oil prices and the Energy Policy Act of 2005. Most gasoline in the US contains 10% bioethanol and there needs to be a technological leap in car engines in order to process higher blends. Flex-fuel cars have proven to be a great success in Brazil and motorcycle manufacturers have also started producing such models. However with there being over 250 million cars in the US, it may take up to two decades before most cars are flex-fuel. In 2006, 5 billion gallons of bioethanol were produced in the US and in 2010 this figure reached over 10 billion gallons. With this rate of growth, it is likely to become a large exporter [1] if the price of crude oil is higher than about $100 a barrel. Further demand could arise from the diesel market as it has been established that up to 15% hydrated ethanol can be blended into conventional diesel with the aid of emulsifiers [2]. The rapid rise in bioethanol production in the US will require a larger proportion of agricultural land to be used for nonfood production. Furthermore, local water and nutrients may be diverted to intensive biofuel crop growing regions from food growing regions. Due to increasing concern about food versus fuel competition and the need to improve carbon balance, industry is shifting toward lignocellulosic feedstocks such as crop straws, paper waste, and wood. These feedstocks do not interfere with food production; however, some feedstocks such as straws are used as livestock feed and this large-scale diversion to fuels could have an indirect effect on meat supplies. However in many areas of the world there is a surplus of straw available which would not create such a problem [3]. Similar to straws, corn cobs are rich in cellulosic material and could be used to produce ethanol, supplementing the starch-to-ethanol production. In Brazil, sugarcane bagasse is already being utilized to generate bioelectricity for the sugar mills and the local grid. Many companies such as Abengoa are now actively working on demonstration plants that produce bioethanol from waste straws and the key challenge globally is to reduce the high cost of production. Lignocellulosic-derived ethanol is currently
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The Ensus plant, the largest wheat to ethanol plant in Europe, commenced production in February 2010. Permission obtained from Ensus. Figure 6.2
competing with low-priced gasoline and sugarcane/corn-derived bioethanol which makes it difficult for this technology to become substantial in the short to medium term without government subsidy. However the utilization of lignin other than as a solid fuel would improve the situation and although several applications such as carbon fiber [4, 5] have been identified, nothing of value has been developed. With the increasing recognition of the benefits of the bioethanol industry as demonstrated in Brazil, and especially the resulting independence from volatile crude oil prices, other countries are now developing similar plans. The UK is sourcing some of its bioethanol from locally grown animal feed wheat. Ensus, a company based in the north east of England, opened its 400 million liter bioethanol plant in 2010 as shown in Figure 6.2. The coproducts, such as 350 000 tonnes of high-protein dried grain, will be used as animal feed and 300 000 tonnes of carbon dioxide will be used in the production of soft drinks and food each year. Tate and Lyle, a large sugar beet processor in the UK, will use some of its sugar for ethanol production. Worldwide, we see that many countries that grow sugarcane or have the potential to grow it such as Pakistan and Tanzania are rapidly developing bioethanol projects. Companies such as Petrobras which have well-established systems in Brazil are working with governments throughout the world to develop this technology in their countries, and Pakistan is now the second largest exporter of ethanol to Europe after Brazil [6, 7]. As more ethanol will be required to be transported over long distances, the use of existing pipelines will become important.
6.2 Current and Future Outlook for Biofuels
6.2.2 Biobutanol
The transportation of ethanol through existing pipelines is not possible due to its hygroscopic nature, which is a major disadvantage. Due to this, many in the industry are focusing on biobutanol, which does not have such problems and can be produced in a similar method to ethanol using Clostridium acetobutylicum or beijerinskii [8]. Furthermore biobutanol has energy content similar to gasoline, which is higher than bioethanol and can be used in diesel or gasoline combustion engines without modification. Biobutanol can be blended with conventional fuels at any ratio in existing crude oil refineries, and unlike bioethanol it does not damage pipelines, tanks, and other equipment. Biobutanol has a lower vapor pressure than ethanol, which means it is well within the required specification of gasoline and allows low-value octane enhancers such as butane to be used during warm weather [9]. Biobutanol is also an alternative to synthetic butanol which is currently used in the chemical industry as a platform chemical and solvent. Little is known about the effects of biobutanol on car engine materials such as the metal and plastic; therefore further research is required in this field. A recent joint venture of BP and Dupont called Butamax will be producing and marketing biobutanol as a fuel. A technology demonstration plant is expected to be functional by 2010 and will use feedstocks such as corn, wheat, and sugarcane [10]. Other companies such as Cobalt Biofuels and Gevo are also working on developing biobutanol as a transport fuel which has a significant future potential. Gevo has obtained funding from Khosla Ventures, Virgin green fund, Burill & company, and Malaysian Life Sciences Capital Fund [11]. Cobalt has received $25 million from a number of investors such as Pinnacle Ventures, Vantage Point Venture Partners, Malaysian Life Sciences Capital Fund, @Ventures, LSP, and Harris & Harris [12]. Some of the facilities which Cobalt has developed are shown in Figure 6.3. 6.2.3 Biodiesel
Although the majority of cars run on gasoline, a significant and growing number of cars run on diesel, particularly in Europe; therefore alternative sources of mineral diesel are important. Biodiesel has been produced from a wide range of feedstocks such as Jatropha, palm, soya, rape, sunflower, animal fat, and used cooking oil via the transesterification process. In Europe, the biodiesel market has been severely affected in recent years by the US government subsidized biodiesel exports. However, strong lobbying by the industry has resulted in the EU imposing tariffs on international biodiesel exporters from summer 2009 [13]. The main challenge for the industry is to produce biodiesel economically and at prices competitive with conventional diesel. The economics of biodiesel production can be significantly improved by employing more environmentally friendly processes during the manufacturing process.
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Figure 6.3 Cobalt biofuels facility in Mountain View, California, USA. Permission obtained from Cobalt Biofuels.
For example, biodiesel manufacturing generates large amounts of salt, soap, waste water, and waste catalyst (alkali), which are largely seen as being a problem due to waste treatment and disposal costs. Clearly a more efficient method would involve recycling the catalyst and it has been shown that by using easily recyclable heterogeneous catalysis [14] less catalyst and less energy are wasted. Furthermore, the use of crude oil derived reagents such as methanol raises questions about whether the final product is actually bio-derived [15]. The use of biomethanol would solve this issue; however due to its relatively high price, it is currently not widely used by biodiesel manufacturers. The enzymatic transesterification of triglycerides has been shown to be a greener alternative to traditional alkali-based methods; however the high enzyme cost is a disadvantage. Research has shown that efficient methanolysis of Jatropha oil is possible using immobilized Enterobacter aerogenes lipase catalysis [16]. This research will be important for countries which are fully supportive of biodiesel production such as in India, where the government has designated 400 000 ha of waste land for the production of Jatropha. Engineered microorganisms can be used to produce diesel as well as a variety of chemicals. Amyris Biotechnologies Inc. has recently opened a demonstration facility, as shown in Figure 6.4, where up to 10 000 gallons of “green” diesel and chemicals can be manufactured. The company uses sugar as a feedstock to produce hydrocarbon diesel, which is comparable to current crude oil derived fuel and, therefore, can be directly used in current cars without blending or modification, unlike fatty acid methyl esters. The facility is located within a major sugarcane processing area in Campinas,
6.2 Current and Future Outlook for Biofuels
Figure 6.4 Amyris renewable products demonstration facility in Campinas, Brazil. Permission
obtained from Amyris.
Brazil, and also applies genetic engineering to transform microorganisms to convert sugar into any one of 50 000 different molecules used in the energy, pharmaceutical, and chemical industries. Furthermore the company has transferred technology for producing artemisinin, an antimalarial drug to the pharmaceutical company Sanofi-Aventis for large-scale development. Biodiesel, being a high-volume product, currently results in large amounts of glycerol by-product which can be used as a feedstock for commodity chemical products, feed applications, materials, and energy. The EU-funded Sustoil [17] project has identified a number of potential applications for glycerol which could result in commercial opportunities. Some of the applications of glycerol are discussed later in this chapter. 6.2.4 Microalgae
As a high-volume biomass source, microalgae have attracted great interest, in particular for biodiesel production. These microscopic photosynthetic organisms are significantly more efficient in converting solar energy into biomass in their phototrophic form; however, they can also switch to heterotrophic growth where they depend on glucose as a feedstock. Microalgae can be grown in photobioreactors and open pond systems. Photobioreactors require high capital infrastructure costs, and low-value products such as biodiesel do not make the process economically viable. In open pond systems, there are serious problems of
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contamination by other organisms which can only be alleviated by the use of extreme conditions, which means only a limited number of tolerant algae organisms can be used. Furthermore, the costs of harvesting and drying make the process difficult to commercialize on a large scale. Due to the high efficiency of photosynthesis and the yields of biomass being significantly higher per area of land, many companies and investors have tried to reduce the costs and take on the above challenges head on. Some of these are shown in Table 6.1. ExxonMobil has invested $600 million in algae technology and this is the boldest move made by the industry so far. In partnership with Synthetic Genomics, the algae cells have been engineered to secrete the triglyceride oil. This means the oil floats on top of the culture vessels so there is no need to harvest the algae [19].
Table 6.1 Key achievements of some companies which use algae as a feedstock [18].
Company
Key achievements – Scientific and commercial
AlgaeVenture Systems
The process can reduce the cost of dewatering by 98% compared to centrifugation.
Algenol–Dow Chemical
The company will build and operate a 24-acre Texas-based algae biorefinery demonstration farm that will produce ethanol as a chemical intermediate at a target cost of $1 per gallon.
Aquatic Energy
Open-pond system that is yielding 2500 gallons per acre without using an external CO2 source.
Aurora Biofuels
Projected $1.30 cost for algae in its second-generation technology, due in 2013. The company completed an 18-month pilot earlier this year.
OriginOil
A one-step process for algae dewatering and oil extraction.
Petro Algae
The company’s model farm is 12 500 acres and produces 60 Mgy of fuel. Licensing commenced in 2009 with an Asian deal focused on China and part of southern Japan.
Sapphire Energy
The company has raised $100 million of funding. It has indicated it will be at 1 Mgy in production by 2011 and 100 Mgy by 2018.
Seambiotic
Agreement with NASA Glenn Research Center to develop an on-going collaborative R&D program for optimization of open-pond microalgae growth processes.
Solazyme
Recently raised $57 million of funding.
Solix Biofuels
Has raised $16.8 million funding which will be used to finance construction and commencement of operations at the company’s Coyote Gulch Demonstration Facility, which should be operational by late 2009.
6.3 Chemicals from Renewable Resources
There is the possibility that in a photobioreactor system, the oil and algae water may become an emulsion-type mixture and cause further separation problems. In an open pond system, a thick layer of oil may prevent the light penetrating to the algae and inhibit the algal growth.
6.3 Chemicals from Renewable Resources
The demand for chemicals derived from renewable resources is growing due to a volatile and generally rising crude oil price, concerns over the long-term supply of petrochemical commodity chemicals, and consumer demand for “greener” alternatives. Governments, notably the EU, are also seeking to encourage the use of bioresources and the production of sustainable bioproducts including chemicals. It is of great importance that the principles of green chemistry are applied when manufacturing such chemicals [20]. A report by the US Department of Energy in 2004 identified a large number of chemicals and materials that can be derived from biomass, as shown in Figure 6.5, out of which 12 value-added chemicals were shortlisted. We have examined the most recent developments in the synthesis and commercialization of the bioresource-derived chemicals below. 6.3.1 Succinic Acid
Succinic acid is an important commodity chemical with uses in a wide variety of applications such as food additives, soldering fluxes, pharmaceutical products, surfactants, green solvents, and biodegradable plastics. It is used as an intermediate for the synthesis of 1,4-butanediol, tetrahydrofuran, γ-butyrolactone, and linear aliphatic esters [21]. Novel biodegradable plastics such as polybutyrate succinate and poly(1,3-propylene succinate) can be made using succinic acid. In 2006, the US market for succinic acid was 4.5 × 108 kg/year with a market price of $2.8/ kg [22]. Succinate is currently produced from hydrocarbons for all nonfood applications and from sugar fermentation for food applications [23]. It is well known that glycerol can be converted to succinate salts by fermentation with engineered Anaerobiospirillum succiniciproducens [24] and Escherichia coli. Due to the high costs associated with separation and purification of the succinates from the broth and the formation of by-products, further optimization of the process is required [25]. Yields need to be above 2.5 g/l/h and the costs associated with converting the salts to free acids have to be reduced or eliminated for the process to become economical. The Green Chemistry Centre at the University of York in collaboration with the Satake Centre for Grain Process Engineering at the University of Manchester, both in the UK, has developed a novel method of converting the salt to the free acid in the fermentation broth by direct crystallization, which results in a yield of succinic acid of 70% and a purity of 95% [26]. Furthermore, a novel starch-derived
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Figure 6.5 Examples of chemicals that can be derived from lignocellulosic feedstocks.
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6.3 Chemicals from Renewable Resources
mesoporous solid acid (STARBON®) developed in the Green Chemistry Center has been used to successfully convert succinic acid via esterification to mono/ diesters in high yields and selectivities. Most significantly, it has been shown that Starbon acids can esterify succinic acid while it is in the fermentation broth, in other words in a dirty, dilute aqueous solution. This is important because the separation of hydrophilic, bioresource-derived chemicals from water is likely to be a major challenge for future biorefineries, and esterification is a good, generic method for making the fermentation chemical less hydrophilic and easier to separate. In late 2009, it is expected that a demonstration plant in Lestrem, France, will be fully operational and producing succinic acid from starch using novel enzyme technology. This will allow the process to be optimized and the plans are to produce the chemical at industrial scales by 2011/2012. The project is being financed through a joint venture between DSM (Netherlands) and Roquette (France). A similar joint venture called Bioamber of DNP Green Technology (USA) and Agro-Industrie Recherches et Développements (ARD; France) is now developing second-generation technology in conjunction with the National Research Council of Canada Biotechnology Research Institute (NRC-BRI) for producing succinic acid. The study will be focusing on the use of sugar streams from different feedstocks such as corn, sugarcane, wheat, lignocellulose, and glycerol [27] for succinic acid production. 6.3.2 Aspartic Acid
Aspartic acid can be produced chemically by amination of fumaric acid with ammonia; however, these are asymmetric and hinder the further development of the process. Using biotransformation, aspartic acid can be produced from oxaloacetate (Krebs cycle) via fermentative or enzymatic conversion. Aspartic acid is used to make chelating agents and sweeteners and can be reduced to produce amino analogs of carboxylic acids. The dehydration reaction can be improved by employing solid catalysts (replacing liquid catalysts). The resulting aspartic anhydride can be used as a chemical intermediate. Through esterification, polyaspartic acid (PAA) and polyaspartates can be synthesized but controlling the molecular weight is a challenge. These polymers have several uses and can be used as alternatives to polyacrylic acid and polycarboxylates. It is expected that in the near future, the world’s first sugar-to-(thermal) polyaspartic acid (TPA) plant will be in commercial operation. The plant is being developed in Alberta by Nanochem and the sugars will be locally sourced from sugar beet. The renewable TPA has a market opportunity of $350 million per annum in the dish and laundry detergent industry alone. In the agricultural industry, TPA is known to increase crop yields and in North America the wholesale market is worth $2 billion per annum. Furthermore, the use of biodegradable TPA is mandatory under environmental legislation, for treating oilfield water in some European countries.
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6.3.3 Levulinic Acid
Acid-catalyzed dehydration of sugar feedstocks from lignocellulosic biomass waste produces levulinic acid in yields of 20–25%. The production involves a one-step process using 4.5% hydrochloric acid in water and a temperature of 200 °C for 45 min [28, 29]. The yields can be further improved up to 70% by employing a novel two-reactor system. In this case, sulfuric acid is used with feedstocks from agricultural residues, paper sludges, and organic municipal waste. The method has been validated by two pilot plants in the US [30]. Although the yield is significantly higher, the net energy requirements for the two-reactor system could be higher than normal, which raises environmental and economic concerns. These could be alleviated to a certain extent by generating in-house energy from burning the lignin residues produced during the process. The first commercial facility for the production of biolevulinic acid is currently being commissioned in Caserta, Italy, and will process 50 ton per day [31]. Levulinic acid can be converted to a wide variety of chemical derivatives that serve the industrial and specialty chemicals markets. Reduction leads to methyl tetrahydrofuran (MTHF), which can be used as a fuel additive and a solvent; further reduction of LA yields 1,3-propanediol, a potential alternative building block for the polyester market. Oxidation of levulinic acid leads to acrylic molecules which can be polymerized and blended to change the properties of numerous materials. The damaging health effects associated with bisphenol A (BPA) and resulting concerns over its use in baby bottles, for example, are now well known; however, BPA provides the desirable properties of hardness in polycarbonate materials. Diphenolic acid derived from levulinic acid via condensation can show similar properties to BPA and hopefully put an end to the problems associated with BPA. The synthesis of diphenolic acid can be made more environmentally friendly by employing efficient, reusable, and water-tolerant solid acid catalysts such as mesoporous H3PW12O40/SBA-15 [32]. The polycarbonate resin is valued at around $4/kg and the market is estimated at 2 billion kg/year. Other derivatives such as delta (δ) aminolevulinic acid are valued at $4/kg with a market of over 100 million kg/year in the herbicide industry. An intermediate in the synthesis of delta (δ) aminolevulinic acid is β-acetylacrylic acid which can be used in the production of mass volume acrylate polymers. LA can be converted to lactones which can be used as solvents replacing pyrrolidonones. 6.3.4 Sorbitol Acid (SBA)
Sorbitol acid can be produced in yields close to 100% from glucose via hydrogenation. This makes it very interesting as a chemical for industrial use in the food and nonfood sectors. Every year 350 000 tonnes of SBA is manufactured by companies such as Cerestar–Cargill, Roquette, and Tate & Lyle. For example, isosorbides can be synthesized from SBA via dehydration and can form polymers, which
6.3 Chemicals from Renewable Resources
have similar properties to polyethylene. Polylactic acid, a popular biodegradable plastic currently available on the market can be derived from SBA via hydrogenolysis. Hydrogenolysis leads to glycols which can be used as additives in a wide range of applications such as antifreeze, polyurethanes, and alkyd resins. International Polyol Chemical Inc. (ICPI) has invested in a 200 000 tonne plant which was originally planned to start in 2007 but has been delayed. The plant will produce glycols such as propylene glycol, ethylene glycol, glycerin, and butanediol, starting from sorbitol/glucose. It also aims to use molasses or waste streams such as various pentoses (xylose/arabinose) and lactose derived from whey as feedstocks. 6.3.5 Glycerol
The rapid increase in biodiesel production in the world has resulted in the availability of large quantities of glycerol by-product. The importance of valorizing this by-product is an urgent commercial and scientific challenge as the European biodiesel industry is being crippled by subsidized US biodiesel imports [33]. Glycerol can be used as a building block for many commodity chemicals such as 1,3-propanediol, lactate, and succinate esters. In fact many companies have initiated commercial plans to manufacture high-value chemicals such as epichlorohydrin (Solvay SA) and proplylene diol (Ashland/Cargill) from glycerol feedstocks. The volatility of the price of glycerol and unstable biodiesel volumes has caused concern for these projects. Glycerol has been known since 2800 BC mainly as a by-product of soap production [34]. Currently glycerol has numerous applications in markets such as personal care, food, polyols, alkyd resins, tobacco, detergents, cellophane, explosives, and pharmaceuticals [35]. Leffingwell and Lesser identified 1582 applications for glycerol in 1945 [36]; however in recent times, many glycerol production plants are closing and new plants utilizing glycerol as a raw material are opening [37]. Global glycerol production has increased from 60 000 tons in 2001 to 800 000 tons in 2005 partly due to biodiesel production. The amount of glycerol being used in technical applications is around 160 000 tons and this is expected to grow at a rate of 2.8% per year [38]. Glycerol is a raw material for the production of flexible foams and rigid polyurethane foams. It provides properties such as flexibility, pliability, and toughness in surface coatings and paint [39] regenerated cellulose films, meat casings, and special quality papers. Glycerol has the ability to absorb moisture from the atmosphere and is therefore used in many adhesives and glues to prevent early drying. In food applications glycerol, which is nontoxic, is used as a solvent, sweetener, and preservative. Many polyols such as sorbitol, manitol, and maltitol are used as sugar-free sweeteners; however they are facing fierce competition from glycerol. Glycerol has similar sweetness to sucrose and has the same energy as sugar. Furthermore, it does not raise blood sugar levels and does not feed plaque bacteria. Glycerol is used as an emollient, humectants, solvent, and lubricant in many
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products in the personal care industry such as toothpaste, mouthwashes, shaving cream, and soaps [40].
6.4 The Role of Clean Technologies in Biorefineries
The production of green chemicals depends heavily on clean and efficient technologies which will clearly play a significant role in current and future biorefineries. The fractions from crude oil are separated using well-established fractional distillation processes which are cost-effective and the products are used in various industrial sectors and consumer products. The biorefinery is much more complex than the crude oil refinery as it has to cope with varying feedstocks which need to be processed using several different technologies into chemicals, materials, and energy. Some of the key green chemical technologies are discussed below. 6.4.1 Separation Technologies
Separation technologies are required pre- and post-treatment of the biomass feedstock, which makes them important in the biorefinery. Separating lignin, hemicellulose, and cellulose would significantly increase enzyme digestibility of cellulose to yield higher amounts of sugar. Depending on the type of sugars produced, different derivatives can be synthesized and the resulting fermentation broth can contain a cocktail of chemicals which are required to be separated in an efficient and sustainable way. Other processing technologies such as pyrolysis lead to complex unstable bio-oils, which contain a series of valuable chemicals; however their separation is currently a major challenge. In the US, the production of ethanol is currently based on corn feedstocks and the economics of the process can be improved by extracting valuable products prior to the starch being processed. For example the “zein” which is prolamine-rich is a co-product in the dry corn to ethanol process and has uses in a wide variety of markets including coatings and biodegradable plastics [41]. Zein contains around 50% of the protein in corn and although only a small amount is currently extracted it commands a price of US$10–40/kg. A cost-efficient method of extracting the zein in the dry-grind ethanol industry involves a one-step process based on ethanol [42]. The corn is extracted with 70% v/v ethanol and the extract is then processed using size-exclusion chromatography. The zein can be excluded with 90%+ yields using aqueous ethanol as the mobile phase and other value-added products such as xanthophylls are also readily separated. Therefore an ethanol plant producing 50 million gallons of ethanol per year could produce 13 million kg of zein and 7.5 tonnes of xanthophylls. With zein and xanthophylls having a value $4.4/kg and $5000/kg, respectively, these products could generate $95 million of additional revenue per year.
6.4 The Role of Clean Technologies in Biorefineries
In a biorefinery, the cellulose needs to be separated from the hemicelluloses and lignin to obtain optimal yields of downstream products. There are a number of well-defined processes for the removal of hemicellulose such as alkali extraction with nanofiltration and the organosolv process which is well known for removing lignin. During pretreatment by acid hydrolysis or steam explosion, a number of fermentation inhibitors such as aliphatic acids, furan derivatives, and phenols are also produced alongside the sugars. The removal of these inhibitors is an additional cost to the whole process and therefore improved, low-cost methods are needed. Clearly, depending on the source of the lignocelluloses various concentrations of inhibitors will exist and different processes may be required for different feedstocks and products. For example, volatile components such as acetic acid can easily be removed through evaporation; fractions with a higher boiling point can be removed using a solvent such as ethyl acetate although the solvent needs to be recovered for recycling. The most efficient current method for removing the inhibitors is ion exchange which can remove 84% of the acetic acid from sugarcane bagasse – enough to prevent inhibition and increase the ethanol yield by 30%. Furthermore, the exchange resin can be setup for continuous operation, and specific arrangements of the cationic and anionic exchangers can be applied. Other novel techniques for removing inhibitors include enzyme technology although the costs are still relatively high. In the future, costs can be significantly reduced if hybrid systems are employed which remove the inhibitors, increase fermentation yield, and use less water; these may include extractive-fermentation, membrane pervaporation-bioreactor hybrid, and vacuum membrane distillation-bioreactor hybrid technologies [43]. 6.4.2 Supercritical CO2 Extraction
The technology is based on using CO2 as a solvent which when in the supercritical phase can be tuned to provide a useful range of solvent properties. Although it is costly to achieve the temperatures and pressures required, supercritical CO2 has significant benefits over conventional solvents such as low cost, nontoxicity, nonflammability, and recycling ability [44]. In terms of lignocellulosic conversion, it has been shown that supercritical CO2 improves the enzymatic digestability of hard and softwood [45]. Lignin can be efficiently removed using supercritical CO2 with cosolvents such as ethanol or acetic acid with water [46] which increase solvent polarity. In terms of CO2 as a reaction medium, a novel one-step process involving supercritical CO2 and enzymatic hydrolysis of cellulose has been shown to produce a 100% glucose yield [47]. However, to maintain the high pressure and temperature (160 bar and 50 °C) means the technology may have limited viability for industrial production, but it is an ideal technology for specialty products and possibly for other applications. For example, butyl butyrate can be synthesized via enzymatic esterification and transesterification using a lipase, Novozym 435, under supercritical CO2 conditions. Butyl butyrate is a component of pineapple flavor used by
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the food and beverage industry and due to the use of enzymes is regarded as natural [48]. Another feature of SC–CO2 is that it has a higher diffusion constant and lower viscosity than organic solvents which allows faster travel of reactants and product molecules to and from the enzyme’s active site [49]. The supercritical CO2 technology has been successfully established in a number of industries, including the plant oil processing industry, and therefore has great potential to be integrated in an oil-crop biorefinery. The extraction of premium products such as specialty oils and deodorizer distillate has been well established at the commercial level. As the technology is capital intensive, it does not make sense to process large-volume low-value products but if the technology is a part of a larger biorefinery then it could become feasible. As well as acting as a carbon sequestration technology, it could have multiple uses in a plant oil-based biorefinery; for example it could first be used to extract the oil from the seed and then convert it to products such as biodiesel or edible oil depending on the market conditions. Residual lignin could also be depolymerized yielding valuable aromatic compounds and furthermore the technology would be used to extract valuable components of the plant straw by or using enzymes produce sugars which could be converted to valuable chemicals and bioethanol. A continuous system to process oilseed at commercial level has not been proven and is a future challenge [50]. 6.4.3 Cellulose Hydrolysis
The success of utilizing cellulosic materials for the production of fuels, such as bioethanol, and chemicals depends heavily on reducing the costs of enzyme technology. Enzyme use for the production of bioethanol from sugar and starch has grown significantly and as a result Novozymes is investing $160–200 million in a new enzyme production facility in Nebraska, USA. As discussed elsewhere, the presence of lignin can reduce the efficiency of the enzyme conversion of cellulose to sugars. The lignin forms a barrier between the cellulases and the cellulose and it has also been shown to bind to the enzyme [51]. The yields of sugar can also be increased by genetically engineered enzymes or discovering new microorganisms which manufacture enzymes. The novel enzymes are designed to increase specific activity and operate at high temperatures and specific pH. Novozymes and Genecor have developed very efficient enzymes but are only specific to one substrate. Further research has been undertaken to recycle the enzymes and due to degradation and denaturization during the process, the method has only been proven at lab scale. Due to the complexity of hemicelluloses, a mixture of enzymes is required which increases the cost of production significantly. Carbon Sciences Inc. has developed technology which encapsulates enzymes in a protective shell which has shown to increase the enzyme activity and functional lifespan. The enzymes convert CO2 into gasoline, diesel fuel, jet fuel, and other fuels [52]. Researchers in the US have developed novel genetically modified corn crops, as shown in Figure 6.6, which contain all the enzymes required for cellulose breakdown. Genes found in cow stomachs have been used to modify
6.4 The Role of Clean Technologies in Biorefineries
Figure 6.6 A member of Professor Mariam Sticklens research group working with SPARTAN
III, a genetically modified corn crop for bioethanol production. Permission obtained from Mariam Sticklen.
these crops and the enzymes are only released from the vacuoles with mechanical grinding after harvest [53]. Although the costs of acid hydrolysis have prevented it from being extensively used in biomass conversion processes, HCl Cleantech Ltd has now developed a novel process based on the old industrially proven Bergius method. During the Second World War in Germany, high yields of sugars were obtained from biomass such as wood chips using cold fuming hydrochloric acid (HCl). However, the high costs of recovery and reconcentration of the HCl acid made the process economically unviable. HCl Cleantech Ltd. has now developed a process which allows the HCl gas to be recovered directly from the solution. Thus there is a potential to use this technology on a variety of feedstocks unlike enzymatic hydrolysis which is substrate-specific. The lignin residues are obtained intact and they can be used in other applications or depolymerized. As the process requires small quantities of water and is energetically self-sufficient, it is estimated that the ethanol manufactured using this concept could cost as little as $1 per gallon. Furthermore, the environmentally friendly technology could be applied in other industry sectors
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such as the manufacture of polyvinylchloride. In May 2009, the company announced that it had received venture capital funding from Khosla ventures and Burill & Company. The funds will be used to continue R&D and build a pilot plant in the US [54]. 6.4.4 Thermochemical Processing
A method of converting biomass into desired fuels and chemicals is by using thermal gasification or pyrolysis technology. Gasification technology converts various forms of biomass into gaseous mixtures containing hydrogen, carbon monoxide, methane, and carbon dioxide and these molecules can be used as building blocks for a variety of chemicals and fuels. The gasification system depends heavily on the type of feedstock and correct matching is required for optimal results. The technology for large-scale biomass processing and subsequent gas cleaning using advanced catalysts has still not been demonstrated. Furthermore, the conversion of syngas to biofuels via the Fischer–Tropsch reaction has not been demonstrated and further research into catalysis and technology is required [55]. There are a number of gasification plants around the world which generate electricity such as Guessing, Austria (2 MWe), Lahti, Finland (15 MWe), and Vermont, USA (15 MWe). Cofiring of syngas in existing pulverized coal and natural gas combustors has been successfully commercialized. In order to make gasification technology feasible for fuel and power production, any potential largescale plant will require vast amount of biomass to be transported to the site. The transportation of biomass to central processing locations such as gasification sites or power stations could be made more efficient by using technologies such as pyrolysis. The products of pyrolysis are in the form of gas, liquid, and solid which have direct uses for chemical, heat, fuel, and power applications. Pyrolysis occurs in the absence of oxygen and a variety of biomass feedstocks have been investigated such as wood chips, straws, and energy crops. Furthermore pyrolysis technology could be integrated in biorefineries, for example, glycerin from biodiesel production could be processed to produce valuable products. Lignin is an abundant coproduct of cellulose hydrolysis and has no use in fuel production. Due to evolution, its structure has developed to resist chemical and microbial attack from the environment and, therefore, it is an extremely difficult material to process. Lignin can be easily broken down using pyrolysis to biochar and bio-oil. The bio-oil can be used directly as a fuel in modified combustion engines, and as it contains a cocktail of chemicals it can be used as a feedstock for the chemical industry. The biochar can also be used as a fuel for energy production in coal-fired power stations and biomass boilers. However, there still remain significant challenges with separating the chemicals within the bio-oil. Furthermore stability of the bio-oil is a key issue and as yet no commercialization of the oil has taken place. The biochar can be used as a soil additive or as a solid biofuel; however, research on the effectiveness of the char still remains to be done.
6.6 Conclusions
6.5 The Size of Future Biorefineries
There has been significant debate on the scale of biorefineries and because the “biorefinery” concept can be applied to hundreds of processes, the size is dependent on various factors including biomass availability, economies of scale, and product demand. The transport of biomass is regarded as a key limiting factor for the size of the biorefinery as moving biomass long distances is not efficient due to the presence of futile oxygen and water. However, practically we see that biomass power stations in countries such as the UK will be using biomass imported from thousands of miles away to generate electricity. It seems likely that we will see the development of both small, localized biorefineries that utilize local biomass to satisfy local needs (but may also produce specialty products for export) and larger scale units that are either based on existing infrastructure (typically petrochemical plants, e.g., Rotterdam) or new largescale biorefinery plants (e.g., cofiring power station, bioethanol production, etc.).
6.6 Conclusions
The use of biomass for the production of biofuels and energy faces significant challenges due to the presence and emergence of competing technologies. Many governments around the world are actively pursuing policies to expand nuclear, wind, and solar power generating capacity. The production of clean electricity with very little or no carbon emissions and the security of supply are key drivers for these technologies. Although some countries have sufficient biomass to secure fuel production, many countries would have to import vast volumes of biomass to meet biofuel targets, which means the issue of security would still remain. If in the future the car industry shifts to electric cars, then there will be further demand for electricity generation which could be supplied by nuclear, wind, solar, and biomass. However for aviation and truck transport, there is no real alternative to liquid fuel. Chemicals and materials can only be sourced from earth resources such as crude oil or biomass, unlike energy. Therefore biomass-derived chemicals and materials are the only alternatives to crude oil derived chemical products, which means the future is promising for such applications of biomass. As the price of crude oil increases, traditional petro-platform chemicals such as ethylene and benzene will become more expensive and less widely available. Therefore we have to rethink both our feedstocks for future chemical manufacturing and the platform molecules from which all downstream products will be generated. Braskem is a large petrochemical company in Brazil and it initiated the “green polyethylene” project on April 22, 2009, with an investment of R$ 500 million.
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Commercial operations are scheduled to begin in 2011 with a production capacity of 200 thousand tons per year [56]. This is based on direct substitution of petroderived ethylene, with the same molecule derived from biomass. In most future scenarios, however, we need to think of renewable platform molecules to create the products and effects required by society. While it is possible to reduce the highly oxygenated and functionalized biomass material to hydrocarbons and then use these as substitutes for petro-hydrocarbons, this is an energy-demanding, destructive process which is bound to lead to more expensive feedstocks that we have been used to. It also seems perverse to take away all the functionality which nature provides only to put it back using our less than efficient, and resourceintensive chemistry. The “green polyethylene” project is an illustration of industry only tackling a small part of the problem. The real problem with ethylene-based polymers is that they are not biodegradable, which means they cause considerable harm to the environment including many of the creatures that live in it. For highvolume consumer products such as plastic packaging, we need to take a full life cycle approach.
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7 Economic and Social Implications of the Industrial Use of Renewable Raw Materials Antonio Lopolito, Maurizio Prosperi, Roberta Sisto, and Pasquale Pazienza
7.1 Introduction
The agricultural sector represents the main land use in the countries of the European Union (EU-27), accounting for about 50% of the total land area. By considering its social and economic relevance related to its function as a food producer, agricultural activity is a relevant source of renewable raw materials, playing a key role in the management of natural resources such as soil, water, biodiversity, and landscape [1, 2]. A broadly accepted definition of renewable raw materials refers to “products derived from the agricultural and forestry sectors being used for purposes other than nutrition” [3]. Clear examples can be seen in starch-bearing plants such as potatoes and wheat used for producing paper, cardboard, and adhesives, flax, hemp, and jute used as natural fibers, corn and sugarcane for ethanol production, and rape for biodiesel. With regard to the last two cases, renewable raw materials represent the substitute to fossil energy sources (i.e., coal, gas, and crude oil), which may contribute to the reduction of emissions of greenhouse gases (GHGs), with beneficial effects on the climate change problem. Agriculture has the potential to become a major contributor to bioenergy production in the EU-27 area, by playing a significant role in supporting the huge effort to increase the share of renewable energy sources in relation to total energy production [1]. The formal recognition of agriculture as a source of renewable raw materials started in the early 1990s, when the excess of food crop supply became a controversial issue during the Uruguay Round of the General Agreement on Tariffs and Trade. Since then, the Common Agricultural Policy (CAP) has emphasized the role of nonfood crops for reducing the oversupply of some agricultural commodities. Later, in 1997, the European Agriculture Council defined the so-called European Model of Agriculture as a context in which the agricultural sector does not only play the role of food producer but it also contributes to generate services aimed at rural landscapes protection, biodiversity preservation, promotion of new job opportunities, and enhancing the viability of rural areas. The EU emphasized the relevance of the multifunctional role of agriculture by stressing the strong Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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interdependency between agriculture and regional development [4–6]. In general, multifunctionality refers to a wide range of socioeconomic and environmental aspects generating positive impacts on local communities and rural development. As a result, in June 2003 a reform of the CAP was introduced and changed the way of supporting the farming sector. The CAP was shifted from paying farmers subsidies – which encouraged overproduction – toward measures to support sustainable farming, rural development, and environmental safeguarding. The core aspect of the reform is the introduction of a “decoupling” mechanism on the basis of which payments are no longer linked to production levels, but subject to crosscompliance conditions, which refer to the maintenance of agricultural and environmental resources in good conditions. With regard to the use of raw materials, CAP reform introduces payments for nonfood agricultural products, such as dedicated crops for biofuel production and generation of electrical and thermal energy from biomass [7]. In fact, the production of nonfood crops for energy purposes and biomass started to be a significant source of income for many farmers and an opportunity of employment for many households [8]. The availability of a large quantity of raw materials and the technology for their industrial processing aimed at producing high valuable outputs are the basic conditions for the development and the success of the biorefinery industry in rural areas. According to one of the most accepted definitions, a biorefinery refers to a system of “integrated bio-based firms, using a variety of different technologies to produce chemicals, biofuels, food and feed ingredients, biomaterials (including fibers) and power from biomass raw materials” [9]. A biorefinery may exert different sorts of socioeconomic and environmental impacts. On the one hand, some scholars highlight that biomass production may stabilize the energy supply by reducing the dependence on fossil energy sources. In addition, biomass production represents an additional source for farmers’ incomes [7]; contributes to create new job opportunities [10, 11]; fosters rural economic development [12]; generates environmental benefits such as soil and groundwater protection [2]; reduces GHGs emission [13, 14]; improves forests’ conditions [12]; and reduces toxicity, pathogens, and, as a result, farm-operating costs by lowering agricultural herbicides use [14]. On the other hand, some environmental concerns are related to biodiversity reduction [7, 10, 15], introduction of alien industrial crops [7], acceleration of soil erosion and compactness due to the conversion of grassland to dedicated crops [2], and increases in traffic movements [10]. Furthermore, local citizens may be concerned about the release of particulate matter originating from the combustion devices [2]. With specific regard to the socioeconomic impacts – that is the focus of this study – one can observe how they are very different and vary according to the nature of raw materials, technology, organization of local infrastructure, economic structure, and social profiles of the local context. As emerges from the literature review, there are a number of studies showing various theoretical and methodological approaches to investigate the socioeconomic implications of the intensive use of raw materials in biorefinery industry schemes. The social implications are basi-
7.1 Introduction
cally related to any effect generated by the production of biomass and energy in terms of employment, education, health, and other issues. The economic aspects include financial benefits, local industry creation, infrastructure developments, and others [16]. Under a social and economic perspective, the production of agricultural biomass for energy purposes also opens some questions related to food security and volatility of prices toward agricultural commodities [17]. These are all aspects that are commonly used to evaluate the local, regional, and/ or national implications of implementing particular development decisions. These impacts are typically measured in economic and monetary terms, such as employment and monetary gains, although not all of them are directly measurable. There is a plenty of other intangible aspects, which are normally related to social, cultural, and environmental issues, such as the reputation and the amenities of the area (i.e., natural landscape), which are not always considered in a decision-making process. However the literature seems to be scarce of studies devoted to the analysis of local stakeholders’ expectations and perceptions, which may play a key role in the acceptance and the development of this kind of industry in rural areas. In fact, the nature and the extent of the social and economic impacts of any specific plant will depend on a number of factors: the level and the nature of capital investment, the various institutional and energy policy-related factors (i.e., capital grants and subsidies), the availability of local goods and services that need to be organized locally, and so on. The specific aim of this chapter is to identify, among the large number of socioeconomic aspects, those perceived by local stakeholders as the most relevant in the development of the biorefinery industry.1) Apart from the uncertainty of economic profitability, the success of the biorefinery in rural areas also depends on social acceptance by the local community which may be negatively affected by the lack of the convergence of expectations or the sharing of common fears toward the new industry. Regarding the methodological approach, the economics of complex systems appears to be a promising analytical approach suitable for the analysis and understanding of the phenomenon in which various aspects interact and are mutually influenced, causing emergence, irreducible uncertainty, internal causality, and ignorance. In this way, the analysis provides some knowledge from complexity that may be helpful for the decision-making process [18–20]. With this in mind, and through a case study based on the application of a fuzzy cognitive maps (FCMs) for the territory of the province of Foggia (Italy), a qualitative analysis on the perceptions of local stakeholders has been performed to validate the feasibility of establishing a biorefinery in the area. The result of the analysis is a cognitive map in which the knowledge of stakeholders is drawn. The cognitive map allows the identification of the most-relevant social and economic 1) It is assumed that a technical realization of a large-scale industrial use of renewable resources is possible, and for all discussed scenarios this assumption is
taken as granted. If, for what purpose ever, the technologies should turn out to be not realizable, all scenarios would be invalid.
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aspects related to the development of a biorefinery firm, and to discriminate them into three groups: (i) driving forces, (ii) context variables, and (iii) effects. The structure of the chapter is organized as follows. In the following section, an overview of the role of the biorefinery industry for the development of EU rural areas is described. In Section 7.3, a theoretical framework suitable for an in-depth investigation of the socioeconomic aspects related to the biorefinery industry is presented. The advantages of the economic paradigm based on complex system theory in comparison to the neoclassical one are discussed. In Section 7.4 the results of the application of FCMs to the case study are reported, with the purpose of drawing some elements of discussion regarding the development of the biorefinery industry in rural areas. Finally, the concluding remarks and some suggestions for further research are provided.
7.2 Biorefinery Industry and the Development of EU Rural Areas 7.2.1 Overview of Different Models of Biorefinery Industry
Before entering into the main discussion related to the role of the biorefinery in the rural areas through the analysis of a specific case study, a focus will be made on the differences between the so-called global and local models of this industry. The “global model” is characterized by large-scale production, based on massive investments in countries endowed with natural resources (e.g., Latin America for bioethanol). Raw materials are shipped to industrialized countries, where they are processed by biorefineries and converted into biofuel or ethanol. The existence of relevant economies of scale and the massive investments in agricultural inputs in developing countries is the basis of the large scale of biorefineries and blending companies. The final output is traded to industrialized countries. Both the United Nations Environment Program and the EU Energy Policy assert that producer countries could benefit from the creation of new jobs in this sector. However, whether such development will actually happen strongly depends on which type of agrofuel development will be promoted, which detains its control. Decisions concerning the use of natural resources, or infrastructure developments, have the potential to damage a community’s social well-being if the outcomes are perceived to be unfair. It could be the case where financial groups and multinational corporations are among the most powerful actors of such a system. Other actors may only have a marginal role, acting as peripheral members of the network (e.g., farmer groups and local stakeholders in developing countries). In addition, the system might generate environmental externalities [21], causing discontent and turmoil in local communities. The alternative to the “global model” is based on a smaller scale of production, and could be named “local model.” This model is characterized by the fact that all the phases of its production process are located in the same geographical area,
7.2 Biorefinery Industry and the Development of EU Rural Areas
with a reduction of the economic and thermodynamic inefficiencies related to transportation costs or storage operations. Small-scale producers could (and should) maximize the exploitation of biomass by means of cooperative agreements which would allow them to overcome possible limitations deriving from the scale of production. Hence, in opposition to the global model, the emergence of an innovating niche in rural areas with economies lagging behind represents an opportunity to be considered both within the EU agricultural policy framework and within an overall sustainable energy policy framework. Among the expected benefits, there are: (i) positive environmental effects such as soil protection from erosion, control of the full functionality of streams and rivers, and absorption sinks for CO2; (ii) enhancement of rural amenities; (iii) production and activities diversification; (iv) increases in economic opportunities (energy selling); (v) improvement of local development; and (vi) reduction of depopulation process. Furthermore, by introducing a new biofuel industry, new competencies are required to strengthen the social relations with urban centers, and to revitalize remote areas. Some concerns are related to ecological and social effects. This especially occurs in the case of increased competition between the food and the fuel industries for land to cultivate the dedicated crops. Another aspect is linked to the so-called crossindustry effects, related to what is known as the “Dutch Disease,”2) where the exploitation of natural resources seems to have a relationship with a decline in activity and/or productivity in the manufacturing sector, and/or in traditional forms of agribusiness [22]. This concept works against the idea that rural areas may proceed through paths of industrialization or establish more value-adding activities. An encouraging trend is that in many countries, policy makers are beginning to perceive the potential economic benefits of commercial biomass, for example, employment/earnings, regional economic gains, contribution to security of energy supply, among others. This represents a significant policy change with regard to the old view in which biomass was considered as a noncommercial rural source, or poor man’s fuel [23]. However, it is important to distinguish the potential effects of the establishment of a biorefinery according to the nature, global or local, of the respective schemes. 7.2.2 Potential Effects of the Global Model
Social Aspects Often the social acceptance of large-scale projects, as in the case of a biorefinery, depends on perceptions toward environmental and health 2) The “Dutch Disease” is a term first adopted by The Economist (November 28, 1977, pp. 82–83) to describe the apparent relationship between the increase in exploitation of natural resources and a decline in the manufacturing sector. In 1982, the economists W. Max Corden and J. Peter Neary modeled this
phenomenon by considering two sectors: the booming sector (e.g., the extraction of oil or natural gas, but can also be the mining of gold, copper, diamonds, or bauxite or the production of crops) and the lagging sector (e.g., manufacturing or agriculture).
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questions. On the one hand, there is some evidence supporting the existence of public benefits (such as avoiding carbon emissions, ensuring environmental protection, and security of energy supply at national level). On the other hand, there are strong concerns about the negative implications associated with large-scale production of agrofuels and bioenergy. In this respect, bioenergy has often been associated with overexploitation of natural resources and health hazards. An example of this analysis is presented in Costa and Foley [24] in which it is claimed that while the Brazilian biofuel industry has provided numerous socioeconomic benefits, it has also contributed to agriculture-induced environmental degradation. This study predicts that the deforestation of the Amazon basin will escalate with growing amounts of virgin rainforest being cleared for farmland. In this regard, Charles et al. [25] highlight that greater soil degradation also emerges and the distilling process that converts sugarcane into bioethanol causes odor and dust problems. Further deforestation, especially of high conservation value forests, would lead to a considerable loss of biodiversity. Local climate change as a result of deforestation stemming from biomass production could have irreparable effects, particularly with regard to decreasing levels of rainfall. The social concerns toward these environmental issues are the basis of the low social acceptance by local communities.
Economic Aspects Gilbertson et al. [26] highlight that there is a number of reasons why agrofuels clean development mechanism (CDM) within the Kyoto Protocol may not provide the expected development for local communities. They argue that the structure of the CDM is such that it is usually an option reserved for large companies. These can provide the capital necessary not only to implement the project but also to go through the long process of accreditation and certification, with all the attendant expenses of carbon consultants, third-party verifiers, ongoing project monitoring, and so forth – the CDM is an arrangement under the Kyoto Protocol allowing industrialized countries with a GHG reduction commitment to invest in ventures that reduce emissions in developing countries as an alternative to more expensive emission reductions in their own countries. Therefore, this “reinforces a system in which, ironically, the main entities recognized as being capable of making ‘emission reductions’ are the corporations most committed to a fossil-fuel burning future, while indigenous communities, environmental movements, and ordinary people acting more constructively to tackle climate change are tacitly excluded, their creativity unrecognized, and their claims suppressed” ([26], p.45). Therefore, it would seem very unlikely that small holders would benefit from carbon funding, since money is captured by the big corporations that possess the capital and capacity to enter into the CDM process. According to these views, the promotion and the implementation of biofuels may result in the worsening of problems currently faced by developing countries. Apart from the reduction of food available at regional and/or national levels, the implementation of large-scale schemes of biofuel production might also result in an increase in the food price [27]. Other views highlight how underdeveloped agrarian-based economies rely heavily on food produced either within national boundaries or in
7.2 Biorefinery Industry and the Development of EU Rural Areas
neighboring states. However, a large amount of food is very often imported with significant effects on the increase of national debt [28]. Furthermore, while greater reliance on biomass fuels could promote economic growth in developing countries, it is not clear whether the income generated is shared equally [22]. 7.2.3 Potential Effects of the Local Model
Social Aspects Environment and health issues can be considered as a primary importance for local communities. Usually, small-scale biomass production systems result in local health benefits, either as a result of better wood stove design for people living in rural areas, as a consequence of avoiding emissions of sulfur dioxide or particles when biomass replaces coal in modern power plants, or, even more, as a result of reduced pollution by using biofuels for those living in the many urban centers [23]. Economic Aspects Regarding the economic feasibility of small-scale biorefinery schemes two aspects are particularly relevant, the job opportunities created and the economic gains related to the new industry [23]. In the document “A European Strategy for Sustainable, Competitive and Secure Energy,” the EU Commission has estimated approximately one million new jobs in the EU by 2010 and two million by 2020 deriving from the development of green energy [13]. There is a large consensus on the fact that bioenergy can foster rural development and significantly contribute to employment at local, regional and national level [23, 25, 26]. In many cases it has been proved that bioenergy provides large employment opportunities, and evidence of this is given in some case studies from the rural areas of the EU [23]. Particularly in the EU, biorefinery (together with the other renewable energy technologies) is promoted, with strong government support measures such as targets, tax breaks, and subsidies. Moreover, there is the recognition that the deployment of bioenergy has the potential to improve industrial competitiveness, regional development, and the increase of a strong export industry. For this reason, the EU is planning to introduce a 10% (energy content) agrofuel target for the transport sector by 2020. Establishing sustainability criteria to justify this policy has become a key issue in the international debate on agrofuels and bioenergy, and discussions on the topic are moving ahead at a swift pace [26]. 7.2.4 Which Biorefinery Model for EU Rural Areas?
In addition to the previous observation, large-scale schemes are not strongly linked with local agricultural systems and the rural community since they are highly responsive to biomass world markets (e.g., vegetable oils from Asian or North African countries) instead of locally produced biomass (the so-called zero-miles supply system). Consequently, in rural areas, the large-scale schemes may not activate any virtuous economic effects on local communities and, at the same time,
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local communities could be negatively affected by a high concentration of air particles deriving from intense burning activities of large quantities of biomass. In the case of small-scale schemes, these disadvantages should be avoided since (i) the biorefinery promotes the development of other types of economic activities (e.g., logistics, research and development of green products) and (ii) advantages for energy efficiency due to lower transportation distances. Therefore, in the rural areas small-scale models should be preferred to largescale centralized models.
7.3 From Analytic to Systemic Modeling Methodology of the Biorefinery Industry 7.3.1 The Search for a Theoretical Framework Capable of Dealing with Novelty, Uncertainty, Ignorance, and Unpredictability
The utilization of raw materials in rural areas is an old concept from a historical point of view, since human societies have always used local agricultural goods to satisfy their basic needs (food, heating, housing, clothing). The novelty introduced with the concept of biorefineries relies on the transformation of a large variety of low economic value materials into coproducts and by-products to be used in different manufacturing industries. This brings plenty of uncertainty with regard to the suitability of new materials, the technology necessary for undertaking an industrial transformation, and the discovering of new products devoted to further traditional manufacturing processes. This complexity is the reason for the adoption of a greater variety of approaches to study the main effects of the establishment of a new industry such as a biorefinery. Some of the main theoretical approaches are summarized below.
䉴 A Methodology Review Several approaches have been adopted to study the main effects of the establishment of a new industry such as a biorefinery. At the farming level, Caserta et al. [29] and Ericsson et al. [30] measure the profitability of some energy crops that relies on the calculation of the gross margin and the threshold price. Others focus on the production cost analysis such as a biomass production cost analysis [31], the cost of renewable energy [32], the analysis of cost and benefit flows per unit of carbon [33], the financial returns (gross margin) of energy crops required by farmers [10], and on farmers’ willingness to grow switchgrass for energy production. Jensen et al. [15] used a two-limit Tobit model to ascertain the effects of various farm and producer characteristics on the share of farmland they would be willing to convert. Finally, the study of Yiridoe et al. [14]
7.3 A Methodology Review
evaluates the financial feasibility of alternative investment opportunities through net present value, internal rate of return, benefit/cost ratio, and payback period. Madlener and Myles [34] in their work have systemized socioeconomic impacts according to four different dimensions: social aspects, macro level, the supply side, and the demand side, using the Austrian Biomass Model based on a computable general equilibrium (CGE) model. Other approaches integrate environmental assessments with economic ones. For example, the study of Schneider and McCarl [35] is based on the agricultural sector model ASMGHG that is a US agricultural sector model that also incorporates production and trade activity in the rest of the world. It is a modified and an expanded version of the (ASM) by McCarl used in many economic appraisals of environmental policies to include GHG emission accounting and mitigation possibilities. ASMGHG solutions provide projections for land use and commodity production within the 63 US areas, commodity production in the rest of the world, international trade, crop, and livestock commodity prices, processed commodity prices, agricultural commodity consumption, producer income effects, consumer welfare effects, and various environmental impacts. Krajnc and Domac [11] estimate socioeconomic and environmental aspects of increased use of biomass applying SCORE model. It is based on calculations of costs and normal cash-flow analysis to establish the net impact of bioenergy projects on the chosen region, and it applies the traditional Keynesian Income Multiplier methodology with a strong regional approach. Some studies assess the sustainability by means of the life cycle assessment (LCA) [2]; evaluate the economic, energetic, and ecological sustainability through the integrated farm energy cogeneration (IFECO) approach based on the assumption that farm is an “island economy,” a net energy exporter, as the energy output exceeds the direct energy (cultivation, cropping, plant protection, transport, harvesting, storage) and indirect energy (fertilizer, pesticide, machinery, plantation force, others) used in sunflower cultivation [13]; and estimate the environmental benefits achieved with perennial energy crops replacing annual food crops (value of increased productivity of the soil based on the decrease in cultivation costs, and the value of municipal waste treatment on reduced treatment costs. To calculate the economic value of reduced emissions to water and air, the author used the substitution cost method) [36].
In this chapter, it is argued that the characteristics linked with the uncertainty of the establishment of a new industry are the premises for the adoption of the economics of complex systems, as an alternative to the neoclassical paradigm. The theory of complex systems deals with the evolution of economics, the process of becoming, the structural change, and the emergence of novelty. While neoclassical economics focus on the exchange of goods and services among economic agents aimed at reaching a final equilibrium, the economics of complex systems brings a necessary understanding to disentangle complexity (emergence, irreducible
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uncertainty, internal causality, ignorance) and provides suggestions for decision making [18–20]. The neoclassical approach to natural source and environmental economics deals with scarcity and pollution according to a “mechanical” approach, where the achievement of the general equilibrium guarantees the best solution for all human societies [20]. The perfect and complete information, the achievement of the equilibrium, the rational behavior of economic agents, and the ceteris paribus condition are the main underlying assumption causes of the inadequacy of the neoclassical paradigm. Since the real world is complex, it is assumed that whole multidimensional features are impossible to be fully understood and rationally modeled. Therefore, emphasis is given to empiricism, where the knowledge of the world is generated by experience, rather than by reason [37]. Heckman ([38], p.3) claims that “empirical research is intrinsically an inductive activity, building up generalization from data, and using data to test competing models, to evaluate policies and to forecast the effects of new policies or modifications of existing policies.” 7.3.2 FCMs to Find Knowledge in Complex Systems
The development of computer sciences, the availability of computational equipment at a relatively low cost, and the increasing critical mass in terms of knowledge and competence are the main determinants of the growing interest toward the modeling of complex systems. At present, a large variety of tools and methods are available to tackle the complexity in economic studies. Artificial neural networks, genetic algorithms, nonlinear equation systems, and agent-based modeling are some types of models capable of dealing with the complexity of economic systems. Among the variety of methods available in this work, the FCMs have been chosen to investigate the specific domain of biorefinery development in the context of rural areas. The reasons are various and can be referred to as the following. Firstly, this method is complex enough to model the complexity of the real world. Secondly, it deals with qualitative information that can be obtained by local stakeholders, allowing us to overcome the lack of reliable quantitative data. Thirdly, it is easy to build from the knowledge of local people, and although it does not make quantitative predictions, it is suitable for investigating the effects of the changes in certain conditions affecting the whole system [39]. Basically, FCMs are conceived to draw the causal relationship among the mostrelevant variables describing the behavior of a complex system. Cognitive maps have been introduced for the first time by Tolman [40], as an application for psychology research. Later, FCMs have been applied in several fields, such as anthropology, to represent different social communities in human society [41], ecology, to study the relationships among benthic organisms [42], and policy analysis, to modeling policy scenarios [43]. More recently, Ozesmi and Ozesmi [39] built a model to study the effects of the institutional change on a lake ecosystem based on the perception of the local stakeholders. Coban and Secme [44] modeled the effects of privatization policies on the distilled alcohol sector of Turkey based on
7.3 From Analytic to Systemic Modeling Methodology of the Biorefinery Industry
the perceptions of the employees of alcohol factories, civil servants, and other social groups. The FCM allowed for the prediction of the effects of the policy, under the “what-if” scenario. The assumption underlying this method is that since the real world is complex, knowledge can be obtained from the perception of people involved with a certain issue [43–46]. Although the investigation of complex cognitive maps cannot be very easy, the graph theory from matrix algebra provides a suitable analytical framework. Empirical studies in social sciences are referred to social network analysis (SNA), which is considered a key technique in organizational studies. The first step is to put the map into a matrix form. The variables are listed both on the vertical axis and on the horizontal one forming a matrix, technically called the adjacency matrix [47]. It shows the existing connections between each couple of variables. By examining the adjacency matrix, it can be determined how stakeholders perceive the system. To analyze the features of a cognitive map, several social network indices can be calculated. SNA distinguishes among punctual indices, which refer directly to variable issues, and network indices, which describe the characteristics of the system as a whole. Two useful punctual indices are in-degree (iDvi) and out-degree (iOvi). The indegree shows the cumulative strength of connections (aki) entering the variable i and coming from other variables k: N
iDvi =
∑a
(7.1)
ki
K =1
where N is the number of variables. The out-degree shows the cumulative strengths of connections (aik) exiting the variable i and reaching the other variables k: N
iOvi =
∑a
(7.2)
ik
K =1
On the bases of their in and out degree, it is possible to distinguish three types of variables in a map, which are sender, receiver, and transmitter [44] (Figure 7.1).
S
T
R
iOvi ≠ 0 iDvi = 0
iOvi ≠ 0 iDvi ≠ 0
iOvi = 0 iDvi ≠ 0
Figure 7.1 Types of variables. Abbreviations: S: senders, T: transmitters, R: receivers.
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Sender variables (also called forcing functions, or givens, or tails) have a positive out-degree, and zero in-degree. Receiver variables (also called utility variables, or ends, or heads) have a positive in-degree and zero out-degree. Transmitter variables (means) have both a nonzero in-degree and out-degree. Another punctual index is the centrality (or total degree) [47] of a variable (Ci). It describes the contribution of a variable in a cognitive map showing how connected the variable is to the other variables and the cumulative strength of these connections. This index is calculated as the sum of the variable in-degree and outdegree indices [47–49]: Ci = iDvi + iOvi
(7.3)
Five network indices are commonly used to describe whole network features. The first is the number of variables (N) and accounts for the whole dimension of the system. The second is the number of connections (C), describing the total interaction activities among variables. The number of variables and connections gives a first indication about the complexity of the system. The third is the density, and is calculated as the ratio of the number of connections present (L) to the maximum possible. The maximum number of possible connections depends on the number of variables. If there are N variables in the system, there are N(N − 1)/2 possible unordered pairs of variables and thus N(NN − 1)/2 possible connections among them. The network density is calculated as D=
L N (N − 1)
(7.4)
When its value is 1, the network is fully connected (all possible ties actually exist). If it is 0, no connections are present (completely disconnected system). If the density of a map is closer to 1, it means that the interviewee sees a large number of causal relationships among the variables. The fourth is the index of complexity, calculated as the total number of receiver variables. Indeed, many receiver variables indicate that the cognitive map considers many outcomes and implications that are a result of the system [48]. However, a more advanced measure of complexity is calculated as the ratio of the number of receiver to transmitter variables (R/T). Complex maps will have larger ratios, because they define more utility outcomes and less controlled forcing functions. Finally, the fifth is the hierarchy index (h) [50], based on the out-degree of variables:
h=
12 (N − 1)N (N + 1)
∑
(∑
)
iOvi − iOvi N
(7.5)
When h is equal to 1, the map is fully hierarchical; however, when h is equal to 0, the system is fully democratic. Sandell [51] points out that democratic maps are
7.4 Stakeholders’ Perceptions of Biorefinery in Rural Areas
much more adaptable to local environmental changes because of their high levels of integration and dependence. Thus, stakeholders with more democratic maps are more likely to perceive that the system can be changed [39].
7.4 Stakeholders’ Perceptions of Biorefinery in Rural Areas: Issues and Lessons from the South of Italy
In this section, we report on the organization and results of our analysis conducted in April 2009 in the province of Foggia (Apulia region, Italy). The interest in the area lies in the fact that it is one of the largest agricultural areas in the south of Italy and has a huge potential for producing agricultural raw materials (coproducts and by-products) suitable for biorefinery processing. At the same time, the area is of interest for a broad investigation of the aspects related to the development of biorefinery in rural areas. The large availability of raw materials is basically represented by wheat straw, tomatoes stems, residue from the processing of vegetable crops, arundo grass growing along the river sides, and algae from the natural lake of Lesina. At present, stakeholders are considering the use of biomass for energy purposes, while the concept of a biorefinery is still vague and not yet fully understood. Similar to other rural areas, a traditional chemical industry connected with traditional oil refineries is totally absent. For this reason, recent informative initiatives and academic meetings have been held to stimulate firms toward the opportunities of developing fine chemicals and energy, but other interested stakeholders are mostly concerned about the use of biomass for energy production. To draw the cognitive map, a group of 10 people were interviewed about their perceptions and expectations toward the socioeconomic aspects related to the development of the biorefinery and the use of raw materials. According to the existing related literature [2, 10, 11, 14], different groups of stakeholders are considered. The most recurrent groups reported in the literature are farmers, private entrepreneurs, researchers, technological transfer agents, consumers, local citizens, policy makers, and institutions. The participants were asked to respond to the question “What sort of effects do you expect to derive from the development of a biorefinery industry in this area?” At first, stakeholders verbally expressed and individually described the most relevant aspects. This phase was necessary to share the information in the group. Once they reached a sufficient consensus of perception and expectations among them, they were asked to code the concepts expressed into a concise form, to achieve a compromise between the precision required by the logical definition of concepts, while keeping the necessary vagueness of natural human language. Finally, participants were asked to specify the qualitative causal relationships among every variable. They were also asked to specify the sign (positive or negative) and the intensity of the causal relationship, according to three increasing degrees: weak, moderate, and strong. The final outcome of the participatory meeting was the FCM in graphical form, representing the starting point for the network analysis.
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7 Economic and Social Implications of the Industrial Use of Renewable Raw Materials
7.4.1 A Network Analysis of Stakeholders’ Knowledge
The outcome of the participatory group has been the collection of knowledge from stakeholders on socioeconomic aspects related to the biorefinery industry (Figure 7.2). The resulting map is based on the adjacency matrix (Table 7.1), which shows the whole set of relationships identified by the participants. It consists of 27 variables connected by 34 links, of which a few of them result as being more central than others, depending on the number of connections. The various connections (denoted in the map with directed arrows) assumed a positive effect (black arrows), or a negative (gray arrows), with low, medium, and high degrees of relevance (represented by the thickness of the arrows). A more comprehensive analysis of the emerged system and an objective and rational interpretation of the results are allowed by calculating some network and punctual indices.
Network Indices Table 7.2 describes the system features. The whole network is made of 27 variables, which are classified into 5 senders, 11 receivers, and 11 transmitters. The low density of the network (0.048) can be explained by the fact that stakeholders identified only a small part of the possible connections. This means that, according to their perception, only some paths of interaction are activated among sender, receiver, and transmitter variables. The hierarchy index (0.12) denotes a wide democratic system with few hierarchical relations. This partly depends on the high proportion of transmitters that makes the whole system much more adaptable to context changes by means of their interactions. The insight is that local stakeholders perceive the situation to be easily changable, and may be affected by several variables. Since receivers are much more numerous than senders, a high degree of complexity emerges (2.2). The high value of this index highlights that the system generates a lot of outcomes, while only a few controlling forces are the determinants of its behavior. The other characteristic denoting the complexity of the system is the great number of transmitters, which are playing a relevant role in spreading the stimulus produced by senders to the whole system. According to the perception of stakeholders, the transmitters form a sort of “connective fabric” that can consolidate the whole system. In fact, without the mediating function of transmitters, the senders could directly reach only 4 of the 10 receivers. Punctual Indices By focusing on the logical meaning of each variable, it is possible to classify the variables among four relevant dimensions. Participants agreed on the following four dimensions (see also on Figure 7.3): 1) 2)
Economy, containing 14 variables, related to the local economic system; Territory, including nine elements associated to the sociopolitical and territorial context;
9
Figure 7.2 The local stakeholders biorefinery cognitive map.
4
3
8
5
7.4 Stakeholders’ Perceptions of Biorefinery in Rural Areas 157
17 18 19 20 21 22 23 24 25 26 27
6 7 8 9 10 11 12 13 14 15 16
1 2 3 4 5
Public information and stakeholders’ training Subsidies for biorefinery Competition between food/nonfood crops Geographic dispersion of biomass sources Availability of biomass from spontaneous species Development of biorefinery industry Technological innovation Enhanced use of regional agronomic vocation Transport costs Industrial diversification Partecipatory in public decision making Economies of scale Land use change Market distortions Induced industrial development Uncert. toward the settlement of the new industry Valorization of residues and wastes Job opportunities Biomass supply from dedicated crops Agricultural sector profitability Consumer goods prices Territory’s reputation Well-being of residents Dispersion of biorefinery plants Concentrated biorefinery setlements Competitiveness of firms not involved in BR Technological transfer
N. Variable
R R R R R R R R R R R
T T T T T T T T T T T
– – – – – –
−1
3
3
2
– – – – – 2
S S T
S S S S S S S S
4 5 6
Type 1 2 3
Table 7.1 Adjacency matrix coded from the FCM in Figure 7.15.
2 3
−2
– – – – – – 3 3
T T T
7 8 9
2 2
– –
T 2 –
T
−3
– –
T
T
2
– – – 2 −2
T
2
– –
T
R
3 3
−2 – – –
T
2
2
1
– –
R
3
–
R
3
– –
R
2
– –
R
2
– –
R
−2
– –
R
2
– –
R
2
– –
R
R
−1
– 2 −1 –
R
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
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7 Economic and Social Implications of the Industrial Use of Renewable Raw Materials
7.4 Stakeholders’ Perceptions of Biorefinery in Rural Areas 7
No. of variables
6 5 Economic 4
Terrirorial
3
Enviromental Research
2 1 0 Trasmitter
Ordinary
Receiver
Figure 7.3 Number of variables for each kind. Table 7.2 Indices for the stakeholders’ social cognitive map.
No. of variables Senders Transmitters Receivers Complexity: Ratio No. of receiver/No. of senders (R/S) No. of connections Connection/variable Density Hierarchy index
3) 4)
27 5 11 11 2.2 34 1.26 0.048 0.12
Environment, containing only 2 variables, which impact on the local environmental status; Research, including two variables, that are linked to scientific research and technological transfer.
Table 7.3 shows the specific features of each variable. Among the 5 senders, three of them belong to the economic dimension (subsidies to biorefinery, competition between food/nonfood crops, availability of biomass from spontaneous species), while the others belong to the territorial dimension (public information, geographic dispersion of biomass sources). The most important variable in terms of centrality is public information (centrality: 6). subsidies for biorefinery, competition between food/nonfood crops and geographic dispersion of biomass sources are equally important (centrality: 5), while the availability of biomass from spontaneous crops shows the lowest relevance (value 2 of centrality). Regarding transmitter variables, 6 belong to the economic dimension, while 3 belong to the territorial dimension, 1 to the research dimension, and 1 to the environmental domain. The most central transmitter is development of the biorefinery industry, which is also the most central in absolute. Its connections are many and carry heavy weights. This variable acts as a pulse amplifier. In fact, it receives inputs from two senders and three other transmitters for a total in-degree of 11,
159
Technological innovation
Enhanced use of regional agronomic vocation
Transport costs
Industrial diversification
Partecipatory in public decision making
Economies of scale
Land use change
Market distortions
9
10
11
12
13
14
Transmitters
8
Total
7
–
Availability of biomass from spontaneous species
5
Development of biorefinery industry
–
Geographic dispersion of biomass sources
4
6
E
Competition between food/nonfood crops
3
E
En.
E
T
E
E
T
R
E
T
E
E
Subsidies for biorefinery
2
T
Nature
Public information and stakeholders training
Senders
Variable
1
No.
Table 7.3 Variables list.
4
2
3
2
4
5
6
2
11
–
0
0
0
0
0
0
1
3
3
4
4
3
3
8
19
–
23
2
5
5
5
6
5
5
6
6
8
8
9
10
30
–
23
2
5
5
5
6
2
1
1
1
2
2
2
1
5
–
0
0
0
0
0
0
1
1
1
2
2
1
1
3
9
–
11
1
2
2
3
3
Out-degree
In-degree
Centrality
In-degree
Out-degree
Dichotomic indices
Weighted indices
3
2
2
2
4
3
3
4
14
–
11
1
2
2
3
3
Centrality
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7 Economic and Social Implications of the Industrial Use of Renewable Raw Materials
2 43
T – –
Uncertainty toward the settlement of the new industry
Total
Receivers
2 31
R –
Biomass supply from dedicated crops
Agricultural sector profitability
Consumer goods prices
Territory’s reputation
Well-being of residents
Dispersion of biorefinery plants
Concentrated biorefinery setlements
Competitiveness of firms not involved in biorefinery
Technological transfer
Total
20
21
22
23
24
25
26
27
Abreviations: E: economic; En.: environmental; R: research; T: territorial.
E
T
T
T
T
E
E
E
2
2
2
2
2
2
3
3
5
19
E
Job opportunities
6
18
En.
Valorization of residues and wastes
17
–
2
16
E
Induced industrial development
0
0
0
0
0
0
0
0
0
0
0
0
–
51
1
2
31
2
2
2
2
2
2
2
3
3
5
6
–
92
3
4
15
1
2
1
1
1
1
1
1
1
3
2
–
19
1
1
0
0
0
0
0
0
0
0
0
0
0
0
–
23
1
1
Out-degree
In-degree
Centrality
In-degree
Out-degree
Dichotomic indices
Weighted indices
15
Nature
Variable
No.
15
1
2
1
1
1
1
1
1
1
3
2
–
42
2
2
Centrality
7.4 Stakeholders’ Perceptions of Biorefinery in Rural Areas 161
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7 Economic and Social Implications of the Industrial Use of Renewable Raw Materials
and spreads the impulse to six receivers and three other transmitters with an outdegree of 19. This confirms the initial expectation and is consistent with a social cognitive process built around the item of biorefinery. On the whole, the transmitters capture eight links from the senders (73% of total links departing from the senders), interact within themselves through 11 links (with a total absolute weight of 24), and direct 12 links toward the receivers (for a total absolute weight of 26). This characteristic reflects the property of “connective fabric,” which is essential for the development and success of the biorefinery industry. Concerning receivers, this group of variables receives stimulus from 15 others variables for a total in-degree of 31, thus they act as utility variables or ends of the system. The most relevant variable is the valorization of residues and wastes, which is an environmental variable having an in-degree of six (receiving impulse directly from two transmitters: development of biorefinery industry and technological innovation). In general, economic variables seem to play the most relevant roles in the cognition of interviewees. Indeed, they are the most present in all three types of variables (Figure 7.1). Specifically, in the economic variables we have three senders, six transmitters, and five receivers. Also the territory elements are present in the three groups of variables but their role as transmitters and receivers seems to be less important. Finally, concerning, the environmental and research variables, these are only present in the group of transmitters and receivers but not in the group of senders. 7.4.2 Interpretation of Results
The technical classification of the variables into senders, transmitters, and receivers is the basis for the economic interpretation of the variables reported in the cognitive map, helpful in generalizing the findings of the case study to other rural areas in the EU. For this purpose, the senders are considered as economic determinants of the development of the biorefinery, the transmitters are the influential conditions, while the receivers represent the effects. 7.4.2.1 Determinants A possible interpretation of sender variables is that they could be treated as policy measures aimed at fostering the development of the biorefinery industry.
Public Information The diffusion of adequate information is one of the most important drivers for the development of new technologies. As pointed out by Mayfield et al. [12], the lack of information can leave people with a vague and potentially distorted understanding of the new industry, which may obstruct the complete development and operation of the industry. Public information should be diversified according to the different types of stakeholders. Farmers could be interested in the technical details of cropping practices referred to nonfood crops,
7.4 Stakeholders’ Perceptions of Biorefinery in Rural Areas
the detailed outcomes from local experiments undertaken in small-scale plots, as well as the terms of economic transactions with the biorefinery industry (vertical integration). Private entrepreneurs need information to evaluate their business opportunities, such as details about the market structure and outlook, and the marketing of raw materials (e.g., opportunities from suppliers offering alternative raw materials), and that of the processed products (e.g., threats from concurrent firms producing substitutive products). Local citizens are concerned about the impact of the industry on their quality of life, but also the creation of job opportunities. The information provided to consumers may stimulate the emergence of new expectations and needs (e.g., the substitution of traditional goods with more environmentally friendly ones derived from biorefinery processes). However, the (partial) substitution of petroleum-based technologies with those derived from the biorefinery industry may cause a significant increase on production costs, leading to an overall increase in the consumers’ final goods price. Research centers and technological transformation agents play a primary role in the creation of scientificbased knowledge and its diffusion. Their suggestions and predictions may provide the necessary support for the decision-making process. The adequate availability of information to stakeholders facilitates participatory public decision making, which may have a pervasive influence on crucial economic issues (e.g., transportation cost reduction, achievement of economies of scale, reduction of uncertainty).
Subsidies for Biorefinery The literature identifies government support as a typical incentive for biorefinery schemes [12, 26]. Such incentives are conceived as especially important at the start-up stage, for industrial research and for investments. This aspect appears as the most influential force for the development of a biorefinery industry. Tax breaks and direct support to biorefinery enterprises are among the most traditional policy measures. In addition, there are also other types of indirect support, such as the voluntary or mandatory targets for the supply and demand of biorefinery products (e.g., municipal transportation committed to substitute a part of fuel need with biofuel). Such incentives are justified on the grounds that biorefinery production could bring local environmental and socioeconomic benefits. However, if they last for a long time, they may cause market distortions, as well as a competitive loss for the firms not involved in biorefinery schemes. Competition between Food/Nonfood Crops The equilibrium between food and nonfood crops allows an enhanced use of regional agronomic vocation. In this regard, the CAP reform has already adopted a new orientation by fostering the diversion of farmland toward the use of nonfood purposes, while reducing the direct support for the traditional food crops. However, these policy measures may induce a critical reduction of agricultural land devoted to food crops causing great concerns for the food security issues either at local or global levels. Geographic Dispersion of Biomass Sources The dispersion of biomass sources is an obstacle to the settlement of concentrated biorefinery plants. This effect may not be relevant in so far as diffused biorefinery schemes can be set in the region.
163
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For instance, the creation of a network of preprocessing plants for raw materials may represent a strategy to overcome the problem of distance and transportation costs, since they may be very relevant for the economy of the biorefinery industry. To a certain extent, infrastructural policies may be conceived to enhance the local transportation network to overcome such natural barriers. In addition rural development policies may promote preprocessing plants to collect and concentrate raw materials and to reduce transportation costs.
Availability of Biomass from Spontaneous Species The recent policy for protecting fragile ecosystems is based on the balancing of natural elements and anthropic activities. In this context, the prospective trend of a further enlargement of protected areas will increase the potential supply of heterogeneous and low-cost biomass. Environmental services devoted to the maintenance of these ecosystems will also be conceived to supply a consistent quantity of raw materials at a very low cost. 7.4.2.2 Influential Conditions The technical analysis has highlighted the role of the stronger contribution played by the technological innovation, and the opportunity of enhancing the use of the regional agronomic vocation, which are fundamental components of the territorial capital endowment (physical, natural, social capital). These elements appear strictly interlaced showing evident auto-reinforcing loops which may act as a multiplier effect on the outcomes of the biorefinery system. On the contrary, transport costs may obstruct the opportunity for achieving economies of scale with negative effects on the development of biorefinery. Under this situation, efficient policy making and the enhancement of the transportation system would also effectively pursue the economies of scale. Finally, the biorefinery settlement may originate in a new industrial nucleus from which industrial diversification may emerge. This may lead to the creation of a new industrial district increasing job opportunities. 7.4.2.3 Effects The elements included in the receivers are the aspects that should be monitored to evaluate the possible impacts of the biorefinery industry in the rural area. In most cases, they are political objectives, of great concern to the local stakeholders. From the monitoring of their evolution over time, the contribution of the industry to the socioeconomic development of the area can be assessed. Among them, the value of residues and waste seems to be the most relevant outcome of the industry. This aspect reinforces the concept of biorefinery based on the best use of low-cost materials. The creation of job opportunities is the second-most important effect, which is a very relevant social objective. In fact, employment is among the most important aspects affecting the demographic trend, one of the most critical aspects in rural areas. The biomass supply from dedicated crops deserves to be monitored, to avoid imbalance between the food and the nonfood sector. This may cause the loss of tradition in local foods, implying the loss of a cultural asset. The last relevant issue is represented by the agri-
7.5 Concluding Remarks
cultural sectors’ profitability, which is the primary objective of the CAP and represents one of the most important indicators for the rural development.
7.5 Concluding Remarks
The work in this chapter is aimed at identifying how the implementation of biorefinery schemes is perceived and accepted in rural areas. The experience referred to the province of Foggia (south of Italy) offered the opportunity to undertake an in-depth qualitative analysis of the socioeconomic aspects related to industry development. For this purpose, some of the main local stakeholders (i.e., representatives of farmers’ unions, R&D centers, industry, consumers, and residents) were invited to attend a workshop where, after having been appropriately oriented in the discussion, they were expected to refer to their perceptions on the economic, social, and environmental determinants and effects resulting from a hypothetical implementation of a biorefinery industry. The replies, analyzed by the FCM, highlighted that the development and the implementation of a biorefinery depends on some main determinants or “drivers,” and also on some preconditions, which we have called “influential conditions.” Another category of aspects is represented by final effects or impacts. For a better specification, drivers can be related to aspects that can be handled by policy decisions. On the other hand, “influential conditions” are all the aspects that may already exist in the territorial context and behave as a sort of accelerator or decelerator of the final effects or impacts generated by the drivers through a series of direct and indirect dynamics. From the specific case study, it is possible to observe how public information and the existence of subsides are perceived and hierarchically ranked among the main determinants, since they are felt to play a positive role in the implementation of a biorefinery. With regard to the “influential conditions,” technology innovation, industrial diversification, and the existence of a significant agronomic vocation of the territory are hierarchically ranked among the most relevant. Finally, in relation to impacts, the significant impacts are perceived as aspects such as job creation, the increase of the agricultural sector profitability, and enhancement of environmental quality through the valorization of residues and waste. Of no less importance are the concentration level of the biomass source (which is categorized as a driver) and the transport cost which is seen as an “influential condition.” For the sake of synthesis, what must be noted is the relevance of the variable represented by public information which – although indirectly – seems to be perceived as the key aspect for a broadly accepted development of a biorefinery at local level. Another relevant role is felt to be played by subsides, which are perceived to transmit a positive feedback directly to the development of a biorefinery, although it is also clear that it is capable of generating negative effects on markets distortion since it may destabilize the equilibrium of the whole local economic system. As it is clear that we are dealing with a complex system, whose observation is not straightforward because of the lack of quantitative data and/or any other
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complete information. In such a situation, the methodology of the construction of cognitive maps can support the policy-making process in identifying the variables which are felt to be among the most important. This can help to build a scale of priorities according to the levels of perceptions and acceptance of the local communities or their institutional representatives. In other words, the construction of cognitive maps can help a policy decision maker in identifying those variables, which should be taken into account for identifying and organizing a policy strategy for the implementation of a biorefinery in a rural area. Certainly, the results arising from the use of cognitive maps are strictly based on the perceptions of the interviewed people. This means that the application of this same method to another place or country is unlikely to give the same results. For this reason, an extension of this application to other rural areas in the EU may provide a comprehensive view of the most-relevant aspects (determinants, influential conditions, and final effects), which can be helpful to address the EU policy in the domain of rural development, bioenergy, and agriculture.
Acknowledgments
The authors are grateful for the constructive comments and suggestions provided by the editor and the anonymous referee. The authors acknowledge the financial support from the European Union 7FP SUSTOIL research program (grant agreement no.: 213637, activity codes ENERGY2007-3.3-03: Developing biorefinery concepts). This research program, started in June 2008 and finished in May 2010, is titled “Developing advanced biorefinery schemes for integration into existing oil production/transesterification plants,” and is coordinated by the University of York.
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analysis. Biomass Bioenergy, 9 (1–5), 45–52. Ericsson, K., Rosenqvist, H., Ganko, E., Pisarek, M., and Nilsson, L. (2006) An agro-economic analysis of willow cultivation in. Poland Biomass Bioenergy, 30, 16–27. Brechbill, S. and Tyner, W. (2008) The Economics of Renewable Energy: Corn Stover and Switchgrass, Bioenergy, ID 404 W, Department of Agricultural Economics, Purdue University, West Lafayette, IN. The Economic Affairs Committee (2008) The Economics of Renewable Energy. Vo.1: Report, the Authority of the House of Lords, The Stationery Office Limited, London. De Jong, B.H.J., Tipper, R., and Montoya-Gòmez, G. (2000) An economic analysis of the potential for carbon sequestration by forest: evidence from southern Mexico. Ecol. Econ., 33, 313–327. Madlener, R. and Myles, H. (2000) Modelling socio-economic aspects of bioenergy systems: a survey prepared for IEA Bioenergy Task 29. Paper prepared for the IEA Bioenergy Task 29 Workshop in Brighton/UK, 2 July 2000. Schneider, U.A., and McCarl, B.A. (2001) Economic potential of biomass-based fuels for greenhouse gas emission mitigation, Working Paper 01-WP 280, Center for Agricultural and Rural Development Iowa State University Ames, Iowa 50011-1070, www.card. iastate.edu (accessed June 2009). Börjesson, P. (1999) Environmental effects of energy crop cultivation in Sweden: economic valuation. Biomass Bioenergy, 16, 155–170. Ramsay, J. (1998) Problems with empiricism and the philosophy of science: implications for purchasing research. Eur. J. Purch. Supply Manag., 4, 163–173. Heckman, J.J. (2001) Econometrics and empirical economics. J. Econom., 100, 3–5. Ozesmi, U. and Ozesmi, S.L. (2004) Ecological models based on people’s knowledge: a multi-step fuzzy cognitive mapping approach. Ecol. Modell., 176, 43–64.
40 Tolman, E.C. (1948) Cognitive maps in rats and men. Psychol. Rev., 55 (4), 189–208. 41 Hage, P. and Harary, F. (1983) Structural Models in Anthropology, Oxford University Press, New York. 42 Puccia, C.J. (1983) Qualitative models for east coast benthos, in Analysis of Ecological Systems: State-of-the-Art in Ecological Modelling (eds W.K. Lauenroth, G.V. Skogerboe, and M. Flug), Elsevier, Amsterdam, pp. 719–724. 43 Axelrod, R. (1976) Structure of Decision, the Cognitive Maps of Political Elites, Princeton University Press, Princepton, NJ. 44 Coban, O. and Secme, G. (2005) Prediction of socio-economical consequences of privatization at the firm level with fuzzy cognitive mapping. Inf. Sci. (Ny), 169, 131–154. 45 Kosko, B. (1986) Fuzzy cognitive maps. Int. J. Man Mach. Stud., 24 (1), 65–75. 46 Kosko, B. (1987) Adaptive inference in fuzzy knowledge networks. Proceedings of the First IEEE International Conference on Neural Networks, vol. II, San Diego, CA, 261–268. 47 Harary, F., Norman, R.Z., and Cartwright, D. (1965) Structural Models: An Introduction to the Theory of Directed Graphs, John Wiley & Sons, Inc., New York. 48 Bougon, M., Weick, K., and Binkhorst, D. (1977) Cognition in organizations: an analysis of the Utrecht Jazz Orchestra. Admin. Sci. Quart., 22, 606–639. 49 Eden, C., Ackerman, F., and Cropper, S. (1992) The analysis of cause maps. J. Manage. Stud., 29, 309–323. 50 MacDonald, N. (1983) Trees and Networks in Biological Models, John Wiley & Sons, Inc., New York. 51 Sandell, K. (1996) Sustainability in theory and practice: a conceptual framework of eco-strategies and a case study of low-resource agriculture in the dry zone of Sri Lanka, in Approaching Nature from Local Communities: Security Percieved and Achieved (ed. A. Hjort-af-Ornãs), Linköping University, Linköping, Sweden, 163–197.
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8 Biobased Products – Market Needs and Opportunities Rainer Busch
8.1 Introduction
The use of renewable resources as raw materials for technical applications is not at all new. Mankind has already used natural materials in the early civilizations in order to meet their basic needs, and the first industrial activities were also largely based on the use of renewable resources [1]. This continued until the beginning of the industrial revolution. Until 1850, all organic consumer products and industrial raw materials were plant based. Within a relatively short period of 150 years, however, society changed from a mainly plant-based economy to an economy based on fossil resources: coal until the end of the 19th century, mineral oil until approximately 1970, and nowadays more and more natural gas. In 1870, wood supplied 70% of the fuel demand, in 1920 70% came from coal, and in 1970 70% from mineral oil. Thus, the use of renewable materials declined significantly over time, mainly due to the extremely low prices for petrochemical resources. Currently, approximately 96% of all organic chemical substances are based on fossil resources. Nevertheless, a substantial number of industries are still based on renewable raw materials (RRMs). Still half of the fibers used in the textile industry are natural materials (cotton, wool, flax) and the oleochemical industry satisfies society’s daily hygienic needs for soaps with detergents that are based on vegetable oils. The building industry continues to use natural fibers for construction insulation purposes. It is well known that petroleum-based chemistry not always offers a realistic alternative to the use of renewable materials. Classic examples are the production of antibiotics and drugs where fermentation processes are much more favorable in terms of yield, selectivity, and process costs and play an increasingly dominant role. Moreover, industrial or “white” biotechnology frequently shows further significant performance benefits compared with conventional chemical technology, that is, higher reaction rates, increased conversion efficiency, improved product purity, lower energy consumption, and significantly reduced waste generation. Process and catalysis technology revolutionized the chemical industry in the 20th century. Now the same thing is happening in the production of industrial Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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chemicals from biomass. A wave of project initiatives is underway globally, which aims to convert renewable resources into industrial chemicals. Industrial biotechnology uses biological systems in conjunction with existing and new conventional chemistry, for the production of useful chemical entities. Biotechnology is mainly based on biocatalysis and bioprocessing (the use of enzymes and cells to catalyze chemical reactions) and fermentation technology (directed use of microorganisms), in combination with recent breakthroughs in the forefront of molecular genetics and metabolic engineering. The application of biobased materials offers significant ecological advantages. Agricultural crops are the preferred starting raw materials, instead of using fossil resources such as crude oil and gas. This technology consequently has a beneficial effect on greenhouse gas (GHG) emissions and at the same time supports the agricultural sector producing the raw materials. The OECD has collected and analyzed case studies for the application of biotechnology in such diverse sectors as chemical, plastics, food processing, textiles, pulp and paper, mining, metal refining, and energy. These case studies show that biotechnology not only reduces the cost but also the environmental footprint for a given level of production. In some cases, capital and operating costs were decreased by 10–50%. In others, energy and water use was decreased by 10–80%, while the use of petrochemical solvents was reduced by 90% or eliminated completely. In a number of cases, biotechnology enabled the development of new products whose properties, cost, and environmental performance could not be achieved using conventional chemical processes or petroleum as a feedstock.
8.2 Definition
The terms “biobased” and “biobased products” will be used very often in this chapter and it is therefore essential to understand what is meant by them. There are many definitions around in the technical and scientific community and in the public and they all not always mean the same. In the United States, the Department of Agriculture defined “biobased products” as “commercial or industrial products other than food or feed that are composed, in whole or in a significant part, of biological products or renewable domestic agricultural materials (including plant, animal, and marine materials) or forestry materials” [2]. The European Commission defines biobased products as “nonfood products derived from biomass (plants, algae, bacteria, crops, trees, marine organisms, and biological waste from households, animals, and food production). They may range from high value-added fine chemicals such as pharmaceuticals, cosmetics, food additives, etc., to high volume materials such as general biopolymers or chemical feed stocks.” The concept excludes traditional biobased products, such as pulp and paper, wood products, and biomass as an energy source [3]. Both definitions consider biobased products as nonfood products, but only the European proposal excludes fossil resources explicitly. It is also essential to under-
8.3 Basic Technology for the Conversion of Renewable Raw Materials
stand that the characteristic “biodegradability” does not play a role in these definitions. A recent work on standardization of biobased products however puts a strong focus on sustainability [3].
8.3 Basic Technology for the Conversion of Renewable Raw Materials
The total annual biomass production on our planet is estimated to be 170 billion tons and consists of roughly 75% carbohydrates, 20% lignin, and 5% of other substances such as oils and fats, proteins, terpenes, alkaloids, etc. Table 8.1 translates this into absolute numbers. Of this total biomass production, only 3.5% or a little less than 6 billion tons is presently being used for human needs, distributed as
• • •
3.7 billion tons for human food use, possibly via animal breeding as an intermediate step; 2 billion tons of wood for energy use, paper, and construction needs; 300 million tons to meet the human needs for technical (nonfood) raw materials (clothing, detergents, and chemicals).
The remainder of the biomass is used in natural ecosystems or is lost through burning or natural mineralization processes [1]. This material is in part available for the production of biobased products. There are in principal four different methods to use biomass as a resource for biobased products. They differ from each other in the degree of chemical processing involved. 1)
Nature already produces the desired structures, and isolation of these components mostly requires only physical methods without chemical modification. Examples comprise polysaccharides (cellulose, starch, alginate, pectin, agar, chitin, and inulin), disaccharides (sucrose and lactose), and triglycerides, lecithin, natural rubber, gelatin, flavors and fragrances, etc. Some present-day production volumes for such products are shown in Table 8.2. The possibilities of producing organic chemicals directly by and from the plant by means of plant biotechnology will increase dramatically. The plant is the “chemical plant” of the future.
Table 8.1 Global annual biomass production [1].
Global renewable resources
Million tonnes/year
Carbohydrates Lignin Others
127 500 34 000 8500
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8 Biobased Products – Market Needs and Opportunities Table 8.2 Volumes of natural products [1].
Chemical product
Amount (million tons per annum)
Sucrose Triglycerides Natural rubber Natural cellulose fibers
115 85 55 20
2)
One-step chemical or biochemical modification of naturally produced structures under (1). Above examples are cellulose and starch derivatives, glucose and fructose, glycerol, fatty acids, ethanol, citric acid, glutamic and lactic acid by fermentation, lactulose, lactitol, and lactobionic acid by isomerization, hydrogenation, and oxidation, respectively, from lactose. Mother Nature offers definitely a variety of fine starting materials for speciality chemicals.
3)
Chemical or biochemical modification of naturally produced structures under (1). In several steps to produce organic chemicals and organic materials. Ethanol can be converted to ethylene, sorbitol and mannitol can be obtained by hydrogenation of glucose and sucrose, respectively. Vitamin C can be produced in several steps from glucose, fatty alcohols, and amines from triglycerides and succinic acid from glucose and CO2.
4)
“Back to C1”-chemistry by degrading biomass chemically or biochemically into small fragments (synthesis gas or methane) and building it up again into the desired structures in a controlled way. This technology is well known under the name “Fischer–Tropsch synthesis” and has been currently studied and improved by many academic and industrial research groups.
8.4 Classes of Bioproducts
Many different industrial bioproducts produced today can be divided into four major classes, based on the respective plant raw materials.
•
Sugar and starch-based bioproducts are derived from, that is, sugarcane, sugar beets, corn, wheat, rice, potatoes, barley, grain, and wood through fermentation and thermochemical processes.
•
Oil and lipid-based bioproducts are derived from, that is, soy, canola, sunflower, or other oil seeds and include mainly fatty acids, oils, glycerin, and a variety of vegetable oils.
•
Cellulose derivatives, fibers, and plastics include products that are derived from cellulose, including cellulose acetates (cellophane) and other cellulose derivatives.
8.5 Current Status
•
Wood chemicals are derived from trees and include tall oil, alkyd resins, rosins, pitch, fatty acids, lignin, and turpentine.
Other classifications cluster biobased products around their potential applications, regardless of which raw material they were made. Biochemical products
• • • • •
bioplastics/biopolymers biosurfactants biosolvents biolubricants chemical building blocks. Enzymes
• • •
technical enzymes food enzymes animal feed enzymes.
8.5 Current Status
Potential markets for bioproducts are wide-ranging, and include polymers, lubricants, solvents, adhesives, herbicides, and pharmaceuticals. While bioproducts have already penetrated most of these markets to some degree, new products and technologies are emerging with the potential to further enhance the performance, cost competitiveness, and market share. In the United States, a strong motivation has developed in the past decade to reduce the nation’s dependence on imported oil and to increase their own energy supplies by using a more diverse mix of domestic resources. A Presidential Order triggered a series of initiatives for the promotion of the use of renewable resources in 1999. The Biomass Research and Development Act in 2000 led to the establishment of the Biomass Research and Development Technical Advisory Committee, which issued the “vision for bioenergy and biobased products in the United States” and the “roadmap for biomass technologies in the United States.” For the production of biobased chemicals and materials, long-term goals have been established, which predict a substantial increase from 5% of the current production of target US chemical commodities in 2001 to 12% in 2010, 18% in 2020, and 25% in 2030. By 2030, a well-established, economically viable, bioenergy, and biobased products industry is expected to create new economic opportunities for rural America, protect and enhance the environment, strengthen US energy independence, provide economic security, and deliver improved products to consumers [4]. In Europe, RRMs as industrial feedstock for the manufacture of chemical substances and products have received attention from policy makers already at the beginning of the last decade. It was recognized that the use of RRMs as industrial
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feedstock is already well established in energy and transport sectors. In 2002, cropderived raw materials entered the political agenda with the establishment of a working group “RRMs” within the European Climate Change Programme. The objective of this working group was to quantify the possible reduction in GHG emissions arising from a wider use of RRM-based materials in manufacturing. This expert group identified four major growth areas for biobased products in Europe [5]:
• • • •
polymers lubricants solvents surfactants.
These four classes of chemicals will be discussed in more detail in the following. 8.5.1 Polymers
Biobased polymers or bioplastics, how they are often called, are chemical products made from monomers from plant- or crop-based resources. They have petrochemical equivalents with the same chemical structure and same properties against which they have to compete in the market. They can win this competition only through a lower price, tax advantages or governmental subsidies. 8.5.1.1 Polylactic Acid Polylactic acid (PLA) is probably the best-known biobased polymer. It is made from glucose by fermentation to its monomer lactic acid. Two molecules of lactic acid are then condensed into the dimer lactide, which is subsequently ring-opened and polymerized to PLA in the presence of a catalyst. There is a remarkable number of industrial processes for this polymer (i.e., Purac, Uhde Inventa-Fischer, Galactic), which are all based on fermentation technology. It should be noted here that there exists no economically competitive industrial petrochemical route to PLA. Among the mentioned biotechnical routes, the NatureWorks® process has probably gained the most attention in the past few years, as it delivers a very pure polymer. NatureWorks is the former joint venture of Cargill and Dow, who developed this process and erected a 140 000 t/a plant in Blair, NE in 2003. PLA finds applications in many areas, preferably in textiles and packaging. Textile applications include clothing, fiberfill for bedding, industrial fabrics such as wall panels, carpet tile, and nonwovens (wipes, diapers, and geotextiles). Packaging applications include coated paper and board for milk, and fresh yoghurt containers, bottles and jars for milk, juice and food oils, candy wraps, compost bags, and thermoformed containers for food and fast food [6]. For the year 2015, a volume of 800 000 tons of PLA has been forecast for packaging applications only in Europe [7].
8.5 Current Status
PLA can also be blended with other polymers. BASF has introduced Ecovio, a polymer blend of 55% of BASF’s biodegradable polyester Ecoflex and 45% PLA, in the market very successfully and has started a major investment to increase both Ecoflex and Ecovio capacities at its Ludwigshafen site in Germany in early 2009 [8]. 8.5.1.2 Polyethylene A classical example for a biobased polymer, which can be made from renewable bioproducts, is polyethylene (PE), which is nowadays produced exclusively by the catalyzed polymerization of ethylene coming directly from the steam cracker, a 100% petrochemical process. Ethylene, however, can also be produced via ethanol coming from glucose fermentation. This is a typical “bio” process. Environmental- and cost-efficiency of the process depend on the feedstock choice. First-pass economic calculations indicate that it will be much more efficient to derive ethanol from sugarcane than from corn or sugar beets. Brazil would therefore be an ideal place for such an ethylene production based on sugar due to its huge sugarcane production. Consequently, two major ethylenefrom-sugar complexes have been announced in recent years. The Brazilian sugar and ethanol producer Crystalsev and the North American plastics manufacturer Dow Chemical had announced a joint venture in mid-2007 to make PE from sugarcane in a 350.000 tons integrated facility in Brazil [9]. Originally projected to come on stream in 2011, the project was however suspended in early 2009 [10]. For the time being, the future of this $1 billion investment remains unclear. Another Brazilian company, Braskem, has already started with the construction of a 200.000 tons plant in Triunfo, Rio Grande do Sul, which is also supposed to start up in 2011 [11]. The current global bioethanol production volume of more than 30 million tons, however, would allow us to cover only 30% of today’s global PE production. Braskem has also taken polypropylene, another bulk plastic, in its focus. At the end of 2009, they announced a research partnership with the world’s leading producer of industrial enzymes, Novozymes. The focus of this cooperation will be on the development of a large-scale production of polypropylene from sugarcane [12]. 8.5.1.3 Others Other biobased polymer types that are currently commercially available in the market, but only in limited quantities, are either derived from starch or cellulose or produced using biotechnological instead of chemical processes. The Italian company Novamont manufactures materials based on plant starch and biodegradable polyesters for more than 10 years. Stanelco in the UK, BIOP in Germany, and Plantic in Austria produce similar starch-based materials. Metabolix and ADM have formed the joint venture Telles to produce and market polyhydroxyalkanoate (PHA) resins based on corn sugar. The Japanese company Kaneka has just recently announced to launch a 1000 mt production facility for the manufacture of Kaneka PHBH, a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate [13].
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8 Biobased Products – Market Needs and Opportunities Table 8.3 Overview of other biobased plastics on the market according to [16].
Renewable base
Manufacturer (trade name)
Application
Starch-based polymers
Novamont (MaterBi) Rodenburg (Solanyl) Plantic Technologies Bioplast (Biotec) Biop
Films, molding, extrusion
Polyhydroxyalkanoates
Kaneka Telles (Mirel) PHB Industrial
Molding, films
Cellulose derivatives
Innovia Films (NatureFlex) FKuR
Films, injection molding
Solvay has announced the production of a 60.000 mt/a PVC plant in Brazil which will produce ethylene from sugarcane ethanol [14]. Genencor and Goodyear presented their concept for the manufacture of tires from synthetic rubber based on renewable biomass during the Copenhagen climate conference in December 2009 [15]. A short overview of these activities for new materials and possible applications is given in Table 8.3. 8.5.1.4 Potential The development of alternative plastics and materials based on renewable resources is already providing opportunities today, and will definitely continue to do so in future. Based on the current state of technology at 5–10% of the plastics market, biobased plastics’ long-term potential is significantly higher. This will not merely involve replacing conventional plastics in individual application areas but also completely new ones will be developed. Biobased plastics’ success will not only be based on compostable types, but also on durable biobased plastics. Biobased plastics will move into new application segments, which traditionally use conventional polymers. It is very uncertain how rapidly this can be realized and depends on multiple factors, as, for example, the legislative framework conditions, price developments of raw materials, and the general economic climate [16]. Biobased plastics are rightly regarded as a technology, which offers multiple perspectives to both industry and society. Never before has a class of materials based on principles of sustainability and having the goal of producing in closed loops been so obviously realized from the outset. COPA, the “Committee of Agricultural Organisation in the European Union” and COGEGA, the “General Committee for the Agricultural Co-operation in the European Union” have estimated the potential of biobased plastics in different sectors of the European economy in 2001 [17]. They forecasted a potential of 2 million tons per year, split to the following sectors as shown in Table 8.4.
8.5 Current Status Table 8.4 Forecasted potential of biobased plastics in Europe [17].
Application
Amount (tones per annum)
Catering products Organic waste bags Biodegradable mulch foils Biodegradable foils for diapers Diapers, 100% biodegradable Foil packaging Vegetable packaging Tire components
450 000 100 000 130 000 80 000 240 000 400 000 400 000 200 000
It should be noted though that this list includes biodegradable and compostable polymers. European bioplastics trade group predicted the annual capacity of 1.5 million tons by 2011 [16], a number that is very similar to the COPA/COGEGA estimate. 8.5.2 Lubricants
In industry, there is no generally accepted definition of the term “biobased lubricants” and therefore, the use of the term “biobased lubricant” is confusing, as it generally refers to a lubricant that is biodegradable, but does not necessarily guarantee the presence of the biobased material. There is a strong need for a standardized nomenclature to describe vegetable oil-based lubricants both in the US and in Europe. The European Commission has recently issued a mandate to the European standardization body CEN to elaborate technical standards including a definition for biobased lubricants (and polymers) [18]. In this context, biobased lubricants are considered as biobased products using the definition in Chapter 2. As such, they are produced from
• • •
unmodified vegetable oils modified vegetable oils synthetic esters from modified vegetable oils.
According to a market opportunity study published in 2008 by the United Soybean Board [19], the total global lubricant demand through 2010 is expected to be about 41.8 million metric tons with an expected growth rate of about 2% per annum. The fastest growth will be in the Asia-Pacific region, particularly in China. The world market is segmented into four application areas as shown in Figure 8.1. According to a Frost and Sullivan study [20], the 2006 European market for biolubricants was 122 000 tons (2.6% of the total lubricant use) with a growth rate of 6.6% per annum from 2006 to 2013. This means a biobased lubricant market volume of 190 000 tonnes in Europe in 2013, where Germany and Scandinavia are the top markets with the Benelux countries set to show a significant growth in
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Figure 8.1 The global lubricants’ market split by application segment.
individual market segments. Other countries, such as France, Spain, and the UK are below 1% [19]. Modern biobased lubricants are mainly based on rapeseed oil, sunflower oil, soybean oil, and animal fats. These oils easily undergo oxidation due to their content of polyunsaturated fatty acids such as linoleic acid and linolenic acid. Efforts have been made to modify the oils to provide a more stable material and a product more competitive in performance to mineral oil-based lubricants. This modification can involve partial hydrogenation of oil and a shifting of its fatty acids to high oleic acid content [21]. Other reported changes that address the problem of unsaturation include alkylation, acylation, hydroformylation, hydrogenation, oligomerization (polymerization), and epoxidation [20, 22]. There is a lot of research work being performed on the genetic modification of vegetable oils to reduce both saturated and polyunsaturated fatty acids. Recent advances in biotechnology have led to the development of genetically enhanced oilseeds that are naturally stable and do not require chemical modification and/or use of antioxidants. A soybean seed developed through DuPont technology presents more than 83% oleic acid as compared to only 20% oleic acid content in conventional soybean oil. High oleic varieties of canola oil, rapeseed, sunflower, and soybean are now becoming standard base oils for biodegradable lubricants and greases. Other research work in the chemical industry puts the focus on the development of monomers from vegetable oils that can be used as polyols in the production of polyurethanes or directly as lubricating fluids. Dow Chemical has developed a polyol from soy oil that is currently being used in its Renuva® process for PU foams and may be suitable, according to Dow, for chemical transformation into the lubricants market [19]. Modern biobased lubricants and greases are biodegradable and nontoxic and therefore especially suitable for environmentally sensitive applications such as agriculture and forestry or any operations at or close to water bodies and in protected areas. The predominant application for biobased lubricants is in hydraulic oils, especially for mobile hydraulic systems, which consume about half the amount of bio oil. Construction machines are the largest application segment within the mobile hydraulic market with about 60% of the sales volume. The second largest segment is agro-machines with 15% of the total sales volume [23].
8.5 Current Status
In these applications, the lubricants are used in engines, gearboxes, chainsaws, tractor transmission hydraulic fluid, industrial hydraulic fluids for process and machinery applications, food-grade hydraulic fluids and greases, greases for use in automotive, rail, road and machinery applications, chainsaw bar oil, gear lubes, compressor oil, and transformer and transmission line cooling fluids, and even as releasing agents in construction. Currently, field tests are continuing on twocycle engine oils, metalworking fluids, and other speciality lubricants. Their market potential is estimated at 90% of the total market volume. It is interesting to note that of the 20 largest lubricant suppliers around the world, only two companies have an oil on the US – BioPreferred list, namely ExxonMobil and Fuchs [19]. Although the market share of biobased lubricants and hydraulic fluids is steadily increasing, these products are more expensive than their conventional equivalents, due to relatively high raw material prices and a not yet fully optimized economy of scale. While the total market of lubricants in Germany was shrinking in 2003, the quantity of premium biobased lubricants has increased by 12% annually during the last 4 years. The goal is to increase sales in other European countries and with this be able to carry out price reductions due to higher turnover quantities [23]. A government-sponsored Market Introduction Program (MIP) for biolubricants in Germany, which was launched in 2000 and came to an end in December 2008, was very successful and helped to increase the market share of biobased hydraulic fluids by 150% between 2000 and 2008 [24]. 8.5.3 Solvents
Industrial solvents are used in adhesives, paints and coatings, pharmaceuticals, inks and printing, semiconductor manufacturing, and metal cleaning. According to SRI Consulting, the annual global consumption of solvents in 2005 was estimated at nearly 20 million tonnes [25]. Solvents can be classified by their chemical structure as shown in Table 8.5. Biosolvents, or solvent replacements from biological sources, have the potential to dramatically reduce the amount of environmentally polluting VOC released to the atmosphere. They also have the advantage that they are sustainable. However, there remains much work to be done to make their production cost-effective enough for them to compete with traditional solvents. Table 8.5 Solvent classes [25].
Solvent family
Typical types
Oxygenated solvents Hydrocarbon solvents Halogenated solvents Miscellaneous solvents
Alcohols, ketones, esters, and glycol ethers Aliphatics and aromatics Methylene chloride, perchloroethylene, and trichloroethylene Nitrogen-containing solvents
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Examples for biobased solvents include
• • • •
methyl soyate (soy oil methyl ester) ethyl lactate (fermentation-derived lactic acid reacted with ethanol) D-limonene (extracted from citrus rinds) PHA (from fermentation of sugars or lipids).
Fatty acid methyl ester of soybean oil is an excellent biobased solvent, and is produced by transesterification of soy oil with methanol resulting in a mixture of soy fatty acid methyl esters. Methyl soyate-based solvents have been introduced in the market in the recent years. They match or even surpass the performance of some conventional solvents while being cost competitive. Methyl soyate exhibits superior solvency, is readily biodegradable, and has a low toxicity when compared to other common chemicals. The diversity of the structure and inherent functionality of vegetable oils make them prime candidates for use in polymers and resins. The fatty acid chain in vegetable oils, which is of hydrocarbon nature, can be transformed with a spectrum of traditional and breakthrough chemistries to yield high-performance products with desirable properties. The chemistries that are being considered to modify and functionalize vegetable include transesterification, epoxidation, hydroformylation, and metathesis. Transesterification and epoxidation are already being used to modify soy oil for use in industrial products. Hydroformylation and metathesis are well developed for use in petroleum feedstocks. The challenge will be to develop similar catalyst systems that are effective and efficient on vegetable oils. Ethyl lactate is the ethyl ester of lactic acid and is used today in food, pharmaceuticals, cosmetics, and in the manufacture of semiconductors. The global production of ethyl lactate is estimated to be 14–18 000 tonnes per year at a selling price of 2.30–3.00 EUR kg-1 [26]. This price has been a hurdle in the expansion of ethyl lactate beyond its use as a specialty solvent and kept sales volumes low. An increasing production capacity of lactic acid, which is currently seen in the market, has the potential to drive down the price of ethyl lactate and expand the market for solvent applications. Other so-called green solvents available in the market place are propylene and dipropylene glycol, glycol ethers, butanediol, γ-butyrolactone, tetrahydrofurane from hemicelluloses, pine oil, and orange oil. 8.5.4 Surfactants
Surfactants or surface-active agents are organic chemicals that can enhance cleaning efficiency, emulsifying, wetting, dispersing, solvency, foaming/de-foaming, and lubricity of water-based compositions. These properties are derived from the bipolar and amphiphilic character of the surfactant molecules. Surfactants can be produced from petrochemical or oleochemical feedstocks. Consequently they are divided into two classes: synthetic and natural surfactants.
8.5 Current Status
The basic petrochemical feedstocks are ethylene and benzene which are converted to the surfactant intermediates ethylene oxide, linear alkyl benzene (LAB), and detergent alcohols. Oleochemical or natural surfactants are commonly derived from plant oils (coconut and palm oils), from plant carbohydrates such as sorbitol, sucrose, and glucose or from animal fats such as tallow. Oleochemical feedstock sourcing for natural surfactants has been changing in recent years. Animal fats have lost ground in favor of vegetable oils, including the growing utilization of soybean oil [27]. Classical synthetic surfactants are classified by their ionic properties in water and show up in the market as
• • • •
anionic surfactants cationic surfactants nonionic surfactants amphoteric surfactants.
Anionic surfactants are the largest group accounting for approximately 40% of the world production. They show very good wetting and emulsifying properties, but are known for strong foaming. Nonionic surfactants are the second largest group by volume at about 35%. Some of them are based on sugars (polyglucosides, sorbitan esters, sucrose esters) with a strongly increasing demand due to their low toxicity. Cationic surfactants typically have both excellent antibacterial and good corrosion protection properties. Amphoteric surfactants are “mild” and increasingly used in personal care products. Their behavior strongly depends on the pH. Synthetic surfactants have caused huge environmental problems in the past due to their limited degradability and their partial biotoxicity. Improvements in legislation in the industrial countries have led to a significant reduction of this undesired behavior, but in many less developed countries, pollution caused by surfactants is still a problem. Synthetic surfactants can be found in almost any aspect of human life. Their importance is illustrated in Table 8.6, which shows the main application areas and market segments for surfactants.
Table 8.6 Surfactant market segments [28].
Market segment
Market share (%)
Household detergents and cleaners Auxiliaries for textile, leather, and paper Chemical processing Cosmetics and pharmaceuticals Food industry Agriculture Others
54 13 10 10 3 2 8
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In 2000, the total worldwide market for surfactants amounted to approximately 19 million tons [29] with an estimated global growth rate of 3–4% per year and about 2% in the European Union. Nearly half of this amount accounted only for soap. About 3 million tons of all produced surfactants in 2000 were based on renewables such as carbohydrates and/or vegetable oils [29]. The primary plant-based materials are coconut, palm, castor, rapeseed, and soybean oil, with the majority being coconut and palm oil. The use of RRMs for surfactant production currently exceeds by far the amount used for all other purposes (polymers, lubricants, and solvents). Biobased surfactants are surface-active compounds, which are produced extracellularly by microorganisms from carbon sources such as hydrocarbons, crude oil, glucose, sucrose, glycerin, olive oil or fructose. Biobased surfactants have special advantages over their chemically manufactured counterparts because of lower toxicity, biodegradability, and effectiveness at extreme conditions. In addition, they possess surface-active properties differing in many cases from synthetic surfactants. Several biobased surfactants have been reported to have manifold biological activities covering antibiotics, fungicidal, insecticide, antiviral and antitumoral agents, immunomodulators or specific toxins, and enzyme inhibitors [30]. Consequently, their most important applications are anticipated in areas where such properties are desirable like bioremediation of oil spills during offshore drilling [28], as emulsifiers in food additives [31], cosmetics or pharmaceuticals [32], herbicide [33], and pesticide [34] formulations. Biobased surfactants are typically divided into glycolipids, lipopeptides, phospholipids, functionalized fatty acids, and polymeric biosurfactants. Typical representatives of these groups are rhamnolipids, trehaloselipids, sophoroselipids, cellobioselipids, surfactin, liposan, and emulsan. Although the interest in biobased surfactants has globally increased considerably in recent years, they still compete with difficulty against the chemically synthesized compounds on the surfactant market, due to their high production costs. A lot of research efforts have therefore been currently invested to facilitate their industrial development by reducing their production costs, developing alternative production routes, and by a convenient valorization of their specific properties.
8.6 Outlook and Perspectives
The area of biobased products represents a major new market opportunity for domestically grown biomass resources [1]. It will be a new source of revenue for not only those who produce the feedstocks, but also for the farmers and others who are involved in the production of biobased products themselves. Continued research can significantly increase opportunities for biobased products, expand
8.6 Outlook and Perspectives
existing markets, and open entirely new markets. Currently, markets for bioproducts are wide ranging, including polymers, lubricants, solvents, adhesives, herbicides, and pharmaceuticals and their production volume is estimated at several million tons per year. Total production in these markets (biobased and nonbiobased), however, is in the hundreds of millions of tons. The growth opportunities for biobased products are, therefore, enormous. While bioproducts have already penetrated most of these markets to some degree, new products and technologies are emerging with the potential to further enhance performance, cost competitiveness, and market share. McKinsey recently estimated that sales of chemical products based on either biobased feedstock, fermentation, or enzymatic conversion (or a combination of the three) would triple form 50 billion EUR in 2000 to 150 billion EUR in 2012 [35]. Through advanced research, new concepts in the industrial biorefinery could become a reality. In the industrial biorefinery, any combination of biofuels, electric power, materials, chemicals, and other products could be produced from local biomass resources. Using plants as feedstock instead of petroleum or natural gas can potentially reduce the amount of carbon dioxide emitted to the atmosphere. Globally, about 62 Gt of carbon is taken-up by plants annually via the photosynthesis process. Producing chemicals and industrial products form biomass directly reduces the associated carbon released during the production of fossil-based products. Sustained economic growth depends on having a secure supply of raw material inputs. With rapid world growth and continuing changes in consumer demands, there is a need to find additional, and preferably renewable, resources for industrial production and energy needs. The needs are growing to explore the developing technology front to capture opportunities that are provided by renewable resources. Technology advances are beginning to make an impact on reducing the cost of production of industrial products and fuels from biomass, making them more competitive with their equivalents produced from petroleum-based hydrocarbons. Developments in pyrolysis, gasification technology, separation technologies via centrifuges or membranes, and the use of enzymes and microbes as biological factories are enabling the extraction of value-added chemicals and intermediates from plant-based materials at competitive cost. As a consequence, industry is investing in the development of new bioproducts that are steadily gaining the market share [1]. The vision for bioenergy biobased products in the United States has put forward an ambitious goal for bioproducts. The share of target chemicals that are biobased is set at 25% by 2030. In Europe, the Lead Market Initiative, which was launched in 2006 as the European policy for six important sectors, one of which is “biobased products,” aims to facilitate an early adoption of technological innovation on various markets [36]. It is well known that research and innovation for such products has reached a stage where products are ready for market introduction. However, RRMs were only used in small market niches and mostly manufactured
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in small volumes. The long-term growth potential for biobased products will depend on their capacity to substitute fossil-based products and to satisfy various end-user requirements at a competitive cost to create product cycles that are neutral in terms of GHG and to leave a smaller ecological footprint by generating less waste, using less energy and water. Europe is well placed in the markets for innovative biobased products, building on a leading technological and industrial position. Perceived uncertainty about product properties and weak market transparency however hinder the fast take-up of products. Environmental regulations, standardization, labeling, and other measures encouraging Member States to set up demonstration plants have a role to play, as does the Common Agriculture Policy. While a vision looks forward and points to the future potential, it is also recognized that change must start today. Change itself is often continuous, while breakthrough occurs at infrequent intervals. Successful progress in this field of new technology will be achieved by an integrated and multidisciplinary research in a phase approach. Many of the current limitations regarding the use of renewable materials arise from attempts to fit carbohydrate chemistry into a hydrocarbonbased chemistry pattern. In many cases, this is difficult. The use of renewable materials requires the development of concepts around alternative processing. In the short term, modified processes will allow economic use of renewable resources, while long-term opportunities exist via the smart combination of chemistry with advanced engineering and with recent biotechnology advances. Doing the research and development in sequential manner will be slow and take many years. The optimum approach is to ensure coordinated, parallel processing of research results, and key target area. Such an approach should also encourage partnership between the public and private sectors. Plant-based renewable resources are a strategic option to meet the growing needs for industrial building blocks. There will be economic, environmental, and societal advantages from the development of this new resource base. The appropriate mix of R&D, technology development, in combination with market and public policies, can support the development and demonstration of viable chemicals, intermediates, and materials, in combination with fuels, heat, and power supply. The impetus for new bioproducts will continue to come from favorable government policies, the implementation of biorefineries, and the desire to reduce the need of and dependence from imported oil. Perhaps the greatest factor driving the growth of bioproducts will be acceptance by the public, business enterprises, and government that biomass can provide a solution to some of the most pressing global resource problems. The impact of the bioindustry on rural development and economics has not yet been quantified, but could be impressive. Development of a bioindustry will require increase in production and processing of biomass and could provide a boost to rural areas. It could create new income for farmers and foresters. Development of a larger bioindustry would require new processing, distribution and logistics, and new service industries. This could potentially result in positive economic impacts on rural economic growth in many parts of the world.
References
References 1 Thoen, J. and Busch, R. (2006) Industrial chemicals from biomass—industrial concepts, in Biorefineries: Industrial Processes and Products Vol.2 Status Quo and Future Directions (eds B. Kamm, P. Gruber, and M. Kamm), Wiley-VCH Verlag GmbH, Weinheim. 2 US Farm Security and Rural Investment Act of 2002 (H.R. 2646). 3 European Commission (2008) Mandate addressed to CEN, CENELEC and ETSI for the elaboration of a standardization programme for biobased products, issued by the European Commission on 10 October 2008 (Mandate 52/2008). 4 U.S. Department of Energy, Washington, DC (2002) Vision for Bioenergy and Biobased Products in the United States. 5 Current Situation and Future Prospects of EU Industry Using Renewable Raw Materials, A Status Report on a Novel Industry Sector, European Commission, DG Enterprise Unit E.1: Environmental Aspects of Industry Policy, Working Group (2002) Renewable Raw Materials. 6 Malveda, M. (2006) CEH Marketing Research Report Lactic Acid, its Salts and Esters. 7 Gerlach, F. (2009) Biowerkstoff-Report 6, 17. 8 Market Publishers (2008) BASF Announces Major Bioplastics Production Expansion, News Release 18 April 2008, http://marketpublishers.com/lists/2942/ news.html (accessed 12 December 2010) 9 CleanTech (2007) Dow and Crystalsev to make bioplastic in Brazil, http:// cleantech.com/news/1496/dowcrystalsev-bioplastic-brazil (accessed 7 November 2009). 10 Business News Americas (2009) Dow, Santelisa postpone “green” polyethylene project, 5 February 2009, http://www. bnamericas.com/news/petrochemicals/ Dow, (accessed 11 December 2010). 11 Braskem (2007) Braskem Has the First Certified Green Polyethylene in the World, Press Release 21 June 2007 www. braskem.com.br. 12 Braskem (2009) Braskem and Novozymes to make green plastic, Press
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Release 14 December 2009 www. braskem.com.br. Kaneka Corp. (2009) Full-scale Development of the World’s First Completely Bio-based Polymer with Soft and Heat-Resistant Properties, Press release, 10 March 2009. Solvay, S.A. (2007) Solvay Indupa will produce bioethanol-based vinyl in Brasil & considers state-of-the-art power generation in Argentina, Press Release, 14 December 2007. Danisco US Inc. Genencor Division (2009) The world’s first Goodyear concept tires made with BioIsoprene technology arrive in Copenhagen in time for United Nations Climate Change Conference, Press Release, 2 December 2009. European Bioplastics (2010) http://www. european-bioplastics.org/index. php?id=143 (accessed 26 May 2010). Committee of Agricultural Organisation in the European Union (COPA), General Committee for the Agricultural Cooperation in the European Union (COGECA) (2001) Bioplastic market – an overview. European Commission (2008) Mandate 53/2008: CEN mandate for the development of European Standards and CEN Workshop Agreements for Bio-Polymers and Bio-Lubricants in relation to Bio-Based products aspects. Bremmer, B.J. and Plonsker, L. (2008) BIO-BASED LUBRICANTS A Market Opportunity Study Update, Omni Tech International Ltd. Frost & Sullivan Research Service (2007) European Biolubricant Markets. Honary, L.A.T. and University of Northern Iowa (2001) Biodegradable/ Bio-based Lubricants and Greases, Machinery Lubrication Magazine. Schneider, M. (2006) Plant-oil-based lubricants and hydraulic fluids. J. Sci. Food Agric., 86 (12), 1769–1780. Festel Capital (2005) Market Study on the Potential of Renewable Raw Materials Fachagentur Nachwachsende Rohstoffe (FNR) (2010) Annual Report 2008/2009.
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8 Biobased Products – Market Needs and Opportunities 25 Linak, E. (2006) Global Solvent Report: THE GREEN IMPACT, SRI Consulting. 26 Bray, R. (2003) Bio-based Solvents, SRI Consulting, Report No. 206A. 27 Rust, D. and Wildes, S. (2008) Surfactants: A Market Opportunity Study Update, December 2008 Omni Tech International Ltd. 28 Rahman, P. and Gakpe, E. (2008) Biotechnology, 7 (2), 360. 29 Hill, K. (2007) Industrial development and application of bio-based oleochemicals. Pure Appl. Chem., 79 (11), 1999–2011. 30 Deleu, M. and Paquot, M. (2004) From renewable vegetables resources to microorganisms: new trends in surfactants. Compt. Rend. Chim., 7, 641. 31 Bloomberg, G. (1991) Designing proteins as emulsifiers. Lebensmittel-Technologie, 24, 130–131.
32 Stanghellini, M.E. and Miller, R.M. (1997) Biosurfactants: their identity and potential efficacy in the biological control of zoosporic plant pathogens. Plant Dis., 81, 4–12. 33 Rosenberg, E. and Ron, E.Z. (1999) High- and low-molecular-mass microbial surfactants. Appl. Microbiol. Biotechnol., 52, 154–162. 34 Patel, M.N. and Gopinathan, K.P. (1986) Lysozyme-sentive bioemulsifier for immiscible organophosphorus pesticides. Appl. Environ. Microbiol., 52, 1224–1226. 35 McKinsey & Company (2009) White Biotechnology, Press briefing 27 February 2009, http://pdfcast.org/pdf/ white-biotechnology (accessed 12 December 2010). 36 European Commission (2007) A lead market initiative for Europe, COM 860 final, Brussels, 21 December 2007.
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9 Life-Cycle Analysis of Biobased Products Liselotte Schebek
9.1 Introduction: Why Life-Cycle Analysis of Biobased Products?
One major reason for the interest in biobased products is their potential contribution to mitigation of climate change: biobased products are made from renewable resources – products from agriculture, forestry, or biogenic waste – which, during their growth, take up the same amount of CO2 as is released by biological degradation or energetic conversion in the end of the product’s life. This is a generic advantage compared to the use of fossil resources, which releases the inventory of carbon accumulated and stored in the ground millions of years before. Already in 1996, the IPCC Second Assessment Report examined one group of biobased products, namely biofuels, as a possible mitigation option [1]. Since then, specifically biofuels have not only been in the focus of climate policy but also the interest in other groups of biobased products like biopolymers or biobased composite materials has risen continuously. Given the above-mentioned generic advantage of biomass, what are the issues of life-cycle analysis? The analysis of the life cycle, that is, the process chain from resource extraction, processing, use, and end of life, aims at a comprehensive assessment of environmental impacts of a product. Taking into account the full process chain, the first finding is that obviously the “zero-CO2-balance” of biobased products is not the whole story: crop growing as well as processing and transport of biomass consumes energy, which is either provided by fossil fuels or consumes part of the energy provided by renewable materials themselves. In the end, net reductions of CO2 might be far less than that expected when accounting only for the use of the product. Above this, not only CO2 contributes to the greenhouse effect: in the case of biomass, notably the use of nitrogen fertilizers in agriculture results in the release of nitrous oxide (N2O, laughing gas), which is produced by microbial processes in soil. The global warming potential (GWP) of N2O is nearly 300-fold that of CO2, and already early studies on biofuels showed that N2O from agriculture might lead to a major reduction as to the benefit of greenhouse gas (GHG) mitigation.
Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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Talking of environmental impacts of biobased products, there are also other relevant issues apart from climate change. During agriculture, herbicides and pesticides may be used; during production processes, emissions of diverse substances in air or water may take place, and if energetic conversion is the ultimate use, release of fine particulate matter may occur. Aiming at a holistic view on the environment, these possible impacts have to be taken into account as well. Thus, the core issue of life-cycle analysis is to answer the basic questions of “what is the contribution of upstream and downstream processes of a technology or of a product” and of “what environmental problems matter.” The methodological tool to answer these questions is life-cycle assessment (LCA). The development of LCA started in the early ’90s; today, international standards provide a harmonized methodological framework to perform LCA studies. Despite standardization, however, many procedural steps have to be worked out individually for each study due to the complex nature of the problems investigated. This is specifically true for the issue of biobased products: looking back to the first studies on the environmental impact of the use of biomass, the focus of investigation has moved from the rather simple analysis of single processes, for example, the use of fertilizers during farming, to the current debate on indirect land use induced by the global demand for crops for biofuels. In order to provide adequate support for addressing the most urgent real-world problems, LCA itself is subject of a broad research area aiming at developing tailored approaches for coverage of certain areas of economy as well as of specific environmental problems. In this sense, LCA is not a finalized instrument, but rather a dynamic tool for research and analytical insights. This chapter will enlighten the framework and scope of LCA as well as present major findings from LCA studies on biobased products.
9.2 The Methodological Framework of LCA 9.2.1 General Goal and Framework of LCA
LCA generally serves to systematically study environmental impacts of products and services, covering the complete life cycle from cradle to grave and all relevant impacts on the environment. An LCA study covers all processes of production and use as well as of recycling and end-of-life; it assesses flows of materials between these processes and the environment, and aims at establishing a quantitative relation of possible damage to the environment. Because of this comprehensive concept, an LCA study may end up quickly in a rather complex modeling system, where many kinds of information bases, submodels, as well as assumptions and valuations have to be handled. Therefore, transparency and reproducibility of a study are indispensable in order to make use of LCA for research as well as for decision making. Beginning already during the early ’90s, considerable efforts
9.2 The Methodological Framework of LCA
have been undertaken to standardize LCA. A first milestone was the international “Code of Practice” of the Society of Environmental Toxicology and Chemistry (SETAC) [2]. In 1997, the International Standardization Organization published the standard ISO 14040, the first of a series of standards for LCA. This series has been revised in 2006 and subsumed to two standards, ISO 14040 and 14044, which comprehend the methodological framework of LCA and are the general basis for performing an LCA study [3] (ISO 14044: 2006) [4]. 9.2.2 Phases of LCA 9.2.2.1 General Scheme According to the ISO standards, an LCA consists of four stages (see Figure 9.1): goal and scope definition, inventory analysis, impact assessment, and interpretation. In principle, these stages are dealt with in a consecutive manner. However, as further information on the system is revealed only during the course of work of an LCA, adjustments may become necessary and in consequence the stages might rather be reworked in an iterative process. ISO 14040 states an application of LCA, for example, product development and improvement, strategic planning, or public policy making. LCA can be used to not
Figure 9.1 Stages of an LCA (DIN EN ISO 14040, p 17) cited from “Environmental manage-
ment – Life cycle assessment – Principles and framework” (ISO 14040: 2006); German and English version EN ISO 14040: 2006 [3].
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only analyze the process chain of one product in order to identify processes with the highest environmental impacts, but also to compare different products or products with services having an identical function. LCA, according to ISO 14040, cannot be applied for a plant- or location-related analysis without any reference to a specific product or function (e.g., accident analysis or environmental compatibility study). 9.2.2.2 Goal and Scope Definition The clear statement of goal and the intended application and audience (e.g., the commissioner of a study) is the main prerequisite of transparency of an LCA. At the same time, it is the basis for defining the systems boundary of modeling as to space and time as well as to the production systems investigated. Generally, LCA aims at comparing different products, processes, or services in order to support decision making. Such a comparison requires that the function of those products, processes, or services to be compared is clearly defined and is identical as to the benefit for the user. In the ISO Standard, this requirement is expressed by the definition of a so-called functional unit: “The functional unit defines the quantification of the identified functions (performance characteristics) of the product. The primary purpose of a functional unit is to provide a reference to which the inputs and outputs are related. This reference is necessary to ensure comparability of LCA results. Comparability of LCA results is particularly critical when different systems are being assessed, to ensure that such comparisons are made on a common basis.” [3]. Consequently, all results of an LCA will be expressed in relative terms to the functional unit. If the function is, for example, the packaging of a beverage, results will be given in specified per liter of beverage packaged, for example, 100 g CO2eqivalent per liter beverage packaged. For each functional unit, a reference flow will be defined: this is the amount of a product which is required to fulfill the function, for example, in the case of beverage the respective amount of packing. The first phase may also incorporate procedural decisions of how to perform the LCA, for example, the incorporation of a review panel. Specifically, ISO 14040 asks “whether the results are intended to be used in comparative assertions intended to be disclosed to the public”; if so, a critical review, that is, a validation of the study by independent experts, has to be scheduled. 9.2.2.3 Life Cycle Inventory (LCI) An inventory analysis compiles the flows of materials and energy into and out of the system. Necessary work consists of construction of a flow model, data collection, and calculation of results. In other words, the phase of life-cycle inventory (LCI) provides the systems model of the technical system (“product system”) under study, complying with the goal and scope definition. This model consists of certain elements, which in terminology of the ISO standards are the following:
• •
Product flow – products entering from or leaving to another product system. Elementary flow – an elementary flow (also called “intervention”) is any material or energy flow between the natural environment and the product system.
9.2 The Methodological Framework of LCA
There are input and output elementary flows, for example, crude oil entering the system, and carbon dioxide leaving the system, respectively.
•
Intermediate flows – output from a unit process that is input to other unit processes that require further transformation within the system.
•
Process – a process is any activity that transforms inputs into outputs; for example, a chemical reaction, a plan, but also transportation of good. One process can be further divided in subprocesses. The most detailed is called unit process. This is a process which is modeled as “black box” with inputs and outputs (product as well as elementary flows), but is not any more subdivided.
Summing up, the product system is defined as the “collection of unit processes with elementary and product flows, performing one or more defined functions, and which models the life cycle of a product.” In constructing and calculating this product system, there are some methodological problems encountered quite often. First, in a complex product system it will not be possible to tract virtually all flows in every subsystem occurring. According to the standard, all relevant flows have to be assessed and in order to identify those, “cut-off-criteria” may be applied. Mass, energy, and environmental significance may be chosen as criteria; inputs and outputs are included in the assessment if their cumulative contribution is higher than a defined percentage of the overall input or output or environmental impact, respectively, of the system. Another problem is that quite often one process delivers more than one product. Examples may be a chemical reaction with several products, also a power plant generating electricity and heat at the same time. In these cases, input and output flows have to be divided between these products (“allocation”). The way how this problem is dealt with may be decisive for the result of an inventory calculation and is, therefore, one of the most critical procedural steps to be handled in an LCA study. According to ISO 14044, one should in the first place try to avoid allocation, if possible by dividing the unit process into two or more subprocesses, or by “expanding the product system to include the additional functions related to the coproducts.” The latter is known as the approach of systems expansion. As an example, imagine the production of electricity by two types of a power station: type A generates only electricity, that is, only one function, while type B generates electricity and heat, that is, two functions. For comparison, the product system for the additional function – generation of heat – is modeled based on a state-of-the-art technology. The flows connected to that product system are taken into account in one of the following ways: either they are added to the product system of type A power station, augmenting its elementary flows by those generated from the separate production of heat. Or, they are subtracted from product system type B, acknowledging that the joint production of heat in a power station avoids the production of heat elsewhere (“avoided burden approach”). However, it is not always possible or useful to follow these procedures. In that case, ISO 14044 recommends a step-wise approach for the choice of an appropriate method of allocation. In the first place, the division of flows between the respective
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products or functions shall be performed “in a way that reflects the underlying physical relationships between them.” In practice, most often this means a division in relation of the mass or energy content of products. It is acknowledged, however, that this may not be possible or appropriate in every case. So alternatively, allocation may also be carried out between the respective products and functions “in a way that reflects other relationships between them.” Most often, this means that input and output flows are allocated in proportion to the economic value of the products, reflecting the economic interest of the parties in charge of a process. For example, the extraction of ore does not take place because of its bulk mass and in some cases not because of its main metal, but because of the most precious element whose content may be minor but represents the most part of economic value of the ore. A special case of allocation occurs if outputs might be either regarded as coproducts or as waste. The ISO standard requires to identify the ratio between coproducts and waste “since the inputs and outputs shall be allocated to the coproducts part only.” Quite often, it is not clear only by the physical nature of a compound whether it is a coproduct or a waste. Instead, the economic value has to be taken into account: if it is positive, it is considered a coproduct, and if it is negative, a waste. Summing up, it turns out that the problem of allocation often cannot be solved remaining strictly on a natural science based procedure, but that economic issues implying choices and preferences have to be a part of the decision which approach to choose. 9.2.2.4
Life Cycle Impact Assessment (LCIA)
Steps of LCIA According to the ISO Standards The assessment of environmental impacts aims conceptually at understanding complex cause–effect chains, starting, for example, from the emissions of a certain substance into the environment and ending up with a possible damage to man or the environment, for example, the destruction of an ecosystem. Many steps may be necessary to connect the information from LCI – that is, elementary flows – to an ultimate potential damage. The full cause–effect chain has to be described in life-cycle impact assessment (LCIA) at least qualitatively to understand the mechanism for potential damage as far as possible and based on the present state of science. However, the quantitative assessment may take place at an intermediate step of this chain. If so, it is possible to remain at a natural science based assessment of impacts, whereas assessing damage requires a subjective weighting step in order to prioritize, aggregate, and value results from natural science based models. In addition, assessing damage may be connected with a high degree of uncertainty due to the complex nature of many environmental problems which may not yet be fully understood by science. The quantitative assessment of impacts making use of natural science based indicators along a cause–effect chain is the so-called concept of category indicators, on which LCIA according to the ISO Standards is based. It implies three manda-
9.2 The Methodological Framework of LCA
tory steps: at first, the impact categories have to be defined which are relevant for the objectives of the study. Each impact category stands for a certain environmental problem, for example, the issue of climate change. Along with the selection of an impact category, the scientific model to describe the respective environmental problem has to be chosen. Within this “characterization model,” the “category indicator” as well as one or more “category end points” are specified: the category indicator represents the parameter which can be quantified for one impact category, whereas the end points indicate the nature of a possible damage resulting ultimately; in the words of ISO 14044 they describe an “attribute or aspect of natural environment, human health, or resources, identifying an environmental issue giving cause for concern.” The second step of LCIA, called classification, consists in the assignment of each elementary flow resulting from LCI to the impact categories chosen for LCIA. One flow may contribute to several impact categories; vice versa, usually many flows contribute to one impact category. The third step, characterization, is the calculation of category indicator results. This is done by multiplying LCI results with the respective characterization factor provided for the substances contributing. One example of the respective terms used above is presented in Table 9.1 for the impact category climate change. After finishing characterization, all results from LCI as well as LCIA shall be compiled and presented comprehensively before proceeding by further steps. Three optional elements of LCIA are offered within the standards which may follow the mandatory ones: normalization, grouping, and weighting. They aim to support the evaluation of the importance of each category.
Table 9.1 Example of terms for life cycle impact assessment [4].
Term
Example
Impact category
Climate change
LCI results
Amount of a GHG per functional unit
Characterization model
Baseline model of 100 years of the Intergovernmental Panel on Climate Change
Category indicator
Infrared radiative forcing (W/m2)
Characterization factor
Global warming potential (GWP100) for each GHG (kg CO2-equivalents per kg gas)
Category indicator result
kg CO2-equivalents per functional unit
Category end points
Coral reefs, forests, crops
Environmental relevance
Infrared radiative forcing is a proxy for potential effects on the climate, depending on the integrated atmospheric heat adsorption caused by emissions and the distribution over time of the heat absorption.
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Normalization means to compare the result of the characterization to a reference value in order to outline the specific share of the product, process, or service under study. The value derived from characterization is divided by the value for a reference system. An example may be to relate the category impacts of the product under study to the total category impacts of a country or a region. Grouping serves to sort characterization results into several sets, for example, as to geographical relevance (local, regional, globally). In addition, the sets may also be ranked, for example, as to high, medium, or low priority. By weighting, various impact indicator results are converted into comparable figures using numerical factors. Weighting serves to either convert the indicator results or normalized results with selected weighting factors, or to aggregate them across impact categories. ISO 14044 explicitly states that “Weighting steps are based on value-choices and are not scientifically based.” Consequently, transparent documentation and sensitivity check of different weighting systems or procedures are crucial issues. As to the question, which impacts should be considered and which models should be chosen, ISO 14040 states that “the impact categories, category indicators and characterization models should be internationally accepted, i.e. based on an international agreement or approved by a competent international body.” However, the ISO standards themselves do not provide a list of categories or models to be used. Practical Approaches for Impact Assessment The concept of impact categories has been developed during the early ’90s: a working group of the SETAC proposed a first comprehensive list of fields of environmental impacts, the Centre for Environmental Studies of the University of Leiden published in 1992 its methodology, which includes a set of impact categories with characterization and normalization factors [5]. The CML concept has been updated in 2001 and published as “Operational guide to the ISO standards” [6]. Several other comprehensive methodologies for impact assessment and a multitude of models for single impact categories have been developed until now. Generally, models for impact categories can be grouped in two ways: first, according to the type of environmental problem they address, and second, as to the stage in the cause–effect chain for which they provide an indicator. As to environmental problems, the so-called areas of protection (AoP) represent the respective ultimate area in which a damage might occur and which has a societal value that has to be protected. Regarding the latter, these areas are also denoted as “safeguard subjects.” Generally, three AoP are discerned: resource use, human health, and ecological consequences. Thinking in terms of the cause–effect chain, they represent the last stage where effects may take place. Following ISO 14044, the category indicator can be chosen anywhere along this chain. If it is chosen to represent the last stage, it is termed “end-point indicator”; if it represents a medium stage in the cause–effect chain, it is called “midpoint indicator.” Usually, midpoint indicators are based on natural science based models only, whereas endpoint indicators imply far more modeling steps which may take into account also societal values. An example for a comprehensive set of impact categories providing midpoint as well as end-point indicators is the methodology IMPACT2002+ which
9.2 The Methodological Framework of LCA
links 14 midpoint categories to four damage categories, adding climate change as the fourth one to the other three mentioned above [7]. In practice it can be observed that some impact categories are common in nearly every LCA study, whereas others are encountered only rarely. As to their application in practical use of LCA, Baumann et al. sort impact categories in three groups [8]: the first group is baseline categories, for which scientifically accepted characterization methods exist and which are generally included in most LCA studied. The second group is study-specific categories, whose inclusion depends on the goal and scope and on the availability of data. The last group is all other categories, which are or may be environmental relevant but where no scientifically accepted method for assessment is available at present. The group of baseline categories comprises climate change, stratospheric ozone depletion, photo-oxidant formation, acidification, eutrophication, ecotoxicity (freshwater, marine, terrestrial), human toxicity, and land use. Several other approaches for impact assessment exist which do not or only in parts comply with the ISO approach of impact categories. These may be favorable as to be more convenient for the practitioner, for example, in terms of less data necessary or “ready-made” schemes for weighting and aggregation, but there are also assessment methods based on different philosophies for the evaluation of environmental effects. A typology of methodologies can be found in Hofstetter et al. [9]. The most simple approach for the assessment is to use only one indicator, where consumption of material or energy is the most common one: the MIPS concept developed by Schmidt–Bleek [10] quantifies the material intensity per service unit by adding up the overall material input which is needed to produce a product or provide a service. For energy, the framework of the cumulative energy demand (CED) has been developed in a German technical guideline revised in 1997 [8, 11]. These indicators may be used in a set of other indicators; if used on their own, however, they are interpreted as proxies: that is, it is assumed that in some way not defined precisely they represent a broader scope of environmental effects assigned to the use of material and energy, respectively [8]. Huijbregts et al. propose the indicator of nonrenewable energy use (NREU), stating that it represents a practical approach of a proxy because many environmental impacts are related to energy use [12]. Far more sophisticated are “ready-made” LCIA methods which aggregate impacts to even a single score. The most well-known is ecoindicator 99 [13]. The ecoindicator is based on the assessment of impact categories (in this part complying with the ISO standards), which are further outlined to results for three damage categories (human health, ecosystem, quality resources). These, in turn, are combined into a single score using default weighting factors based on cultural theory and gained by a panel approach. Another approach which also provides a “single-score” assessment, but is based on a different concept, is represented by the method of environmental scarcity developed at the Swiss federal environmental agency [14]. It assesses environmental impacts relative to politically defined limit values by providing so-called ecofactors, which are calculated by comparing the annual actual flow of a pollutant
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to its annual flow considered as critical (critical flows) in a defined area (country or region). Summing up, it has to be emphasized that the goal of impact assessment in LCA is not to assess a real damage at a specific environmental site but to assess the generic potential of damage. In spite of this, LCIA uses models and information from environmental science or toxicology which are also used in “real-world assessment,” and the scientific discussion on if and how to make regionalized impact assessment in LCA is on-going. 9.2.2.5 Interpretation The phase of interpretation is important for transferring the detailed and often complex results from LCI and LCIA to a clearly understandable message for the audience of an LCA study. The ISO standards do not describe precise methods for interpretation, but highlight some important issues: results should be clearly related to the defined goal and scope; limitations should be explained; and significant issues as well as to the results itself as to methodological choices during the study should be outlined. As a whole, interpretation should investigate the robustness of the results and provide “a readily understandable, complete and consistent presentation of the results of an LCA.” 9.2.3 Databases and Software for LCA
Comprehensive information and data are required to carry out an LCA. Generally, their acquisition has a major share in the expenditure needed for a study. Depending on the task and means available, data are compiled newly or either obtained from literature searches, or taken from existing databases. For foreground processes, that is, such processes which are specific for the issues of the study, for example, for a certain technical process of the properties of one real product, specific data have to be gathered. For background processes, for example, electric current from the grid, generic data may be used which usually are provided by databases. Several software tools for LCA are in the market. These in most cases provide datasets for important processes in LCI as well as common methods for impact assessment which facilitates the performance of an LCA study considerably. A survey of software for LCA has been published by the Swiss oebu network (http://www.oebu.ch/de/).
9.3 Specific Methodological Aspects for LCA for Biobased Products 9.3.1 Methodological Outline
Different methodological approaches are encountered when surveying LCA studies for biobased products, which have to be taken into account when evaluat-
9.3 Specific Methodological Aspects for LCA for Biobased Products
ing results from studies. First, this applies to the definition of a functional unit. As has been pointed out earlier, the choice of a functional unit is not only a necessary convention for calculation, but it also mirrors the rationale of an LCA study. In case of biobased products, the functional unit may be chosen to be simply the amount of a product, given in kg or tons. If so, the interest concentrates on the production process, neglecting the use phase or assuming that it is the same as for a petrochemical product. However, often the end-of-life phase is included for a comprehensive assessment of the carbon balance. A different rationale is based on the insight that land is the basic resource for the production of biobased products and that this land is limited. If the interest is to assess the most efficient use of limited land for the production of biomass, the functional unit is chosen to be the amount of biomass produced from a certain area, for example, 1 ha of land. This provides the possibility to compare different uses, especially energetic to nonenergetic use of biomass. Last but not the least, if there is a strong interest in the use phase, this has to be mirrored in the functional unit which in this case is chosen according to the specific application, for example, the transportation of goods over a certain distance in the case of biofuels. Accounting for CO2 is indispensable for LCA of biobased products and seems to be straightforward. Still, there are different perceptions encountered in literature [15]. Looking at the full life cycle, CO2 uptake by plants may be counted as a “negative” emission and CO2 output from by incineration of biomass as a “positive” emission. However, it is also a common practice especially in LCA on energetic use of biomass to omit CO2 uptake as well as CO2 emission from incineration. Guinée et al. show that results of inventory may be dependent from which choice for CO2 accounting has been made [16]. In addition, Rabl argues that by explicitly counting CO2, analysis is consistent with the polluter pays principle, and that otherwise CO2 flows may get lost if only part of the life cycle is assessed [15]. Coproduct generation is frequently encountered in process chains for bioproducts. Procedures for expansion of the product system as well as allocation are very different. Larson enumerates six approaches to allocate coproduct credits found from a review of more than 30 LCA studies and concludes that allocation is the main methodological factor for divergent results from LCA [17]. Another issue is the selection of impact categories. Quite often, impact assessment is restricted to the essential categories of climate change and (fossil) energy consumption. Other impact categories included frequently are eutrophication and acidification, which are relevant for agricultural production of biomass as well as for energetic use. As to the latter, also ozone depletion and smog are included in many cases. The impact categories of human and ecotoxicology may be important for the use of pesticides in agriculture; however, they are reported rather seldom due to a lack of data and due to the high complexity of characterization models which causes a higher degree of variation in the assessment results. As to the issue of land use, most studies acknowledge its major importance; still its treatment in LCA studies is limited [18]. Existing methodological approaches are presented in more detail below.
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9.3.2 Accounting for Land Use in LCA 9.3.2.1 Conceptual Aspects for Treatment of Land Use in LCA Apart from the use of biogenic waste, the feedstock for biobased products is provided from agricultural production of crops or from harvesting of silvicultural products. In both cases, land is the primary resource. However, it has become obvious that land is not simply “used” continuously in more or less the same way, but that major changes in land use may be induced by a rising demand of biobased products, for example, the conversion of tropical forests into plantations for sugarcane, which alter the quality of land and the respective ecosystems. This already points to a basic methodological issue as to accounting for land use in LCA: regarding only the fact that a certain amount of, for example, farmland is used for the production of a feedstock, land use may be treated in the framework of LCA simply as a quantitative information in the phase of LCI. The acknowledgment of the environmental relevance of different ways how land may be used, however, is closely related to environmental safeguards, which makes the assessment of land use a native part of impact assessment. Given this double-fold nature, several conceptual ways to treat land use in LCA have been developed. 9.3.2.2 Land Occupation and Land Transformation In LCI, main attention is given to the insight that surface of land is a limited resource. In this sense, land use is included in LCI in the same way as other limited resources, that is, as an input elementary flow. This is the so-called concept of occupancy, where the total area or the area for a certain use (e.g., farm-land or forest) is reported in hectare or some other square measure. The use of land specified in this way is termed as “occupation process.” As an additional information which reflects specifically the competition for available area of land, time of occupation is reported, that is, area of exclusive land use for a given period of time [8]. The latter is termed as “occupation interventions” and is measured in surface-time units (e.g., hectare per year), representing a certain area of land of a given type used over a certain time period (e.g., occupation of 1 ha for farming of corn for 1 year) [19]. Within the above-mentioned concept of occupancy, no information is provided as to what happened to an area of land before or after it was occupied for a specific use. This question is addressed by the concept of transformation. Lindeijer gives the definition that “a transformation process implies the change of a land area from one occupation process to a new type of occupation process (e.g., forest to plantation)” [20]. In LCI, information on transformation of land (transformation intervention) is specified in surface units being transferred from one occupation to the other (e.g., 1 ha of forest converted into road) [19]. Baumann et al. point out that two types of changes may occur due to a transformation process: a change in competition between uses and a change in quality of land [8]. The assessment can only be done relative, and a transformation may lead to a higher or lower quality, regarding what the indicator is used.
9.3 Specific Methodological Aspects for LCA for Biobased Products
9.3.2.3 Impacts of Land Use The scientific discussion on impacts of land use tries to answer the basic question of how to measure the quality of different ways of land occupation. Lindeijer distinguishes three basic types of assessment for land use impacts, acknowledging that they may be overlapping to some part [20]. These types are the functional approach, land use classes, and key indicators. The functional approach, as its name indicates, is based on different natural functions of land. Examples of functions are groundwater protection, habitat resource function, or human resort function. For these functions, scientific measures have been developed, for example, species density as a measure of habitat resource function. As these functions may be highly variable and dependent on regional conditions, generic systems for operationalization in LCIA have been developed [20]. As to the approach of land use classes, different classification systems have been proposed, based, for example, on the IUCN classification of five land use classes ranging from natural systems to systems degraded by pollution and loss of soil or vegetation. The respective classification systems are derived from the discipline of landscape ecology; they account for the naturalness of land and are based on the so-called concept of hemeroby [21]. The development of key indicators aims at a single score indicator to measure effects of land use, which – as pointed out for single-score indicators in general – requires the use of weighting factors. Lindeijer presents several sets of weighting factors for land use classes as well as other approaches for aggregation [20]. One of these is the so-called PAF concept applied in ecoindicator 99. It measures the potentially affected fraction of species, that is, the part of the total number of species in an area which is potentially affected in terms of laboratory test effects. For the implementation of a land use category in the ISO methodological framework of LCI, several category indicators have been proposed. Milà i Canals et al. present an overview of currently used indicators of land use quality, differentiating between three impact pathways: impacts on biodiversity, on biotic production potential, and on ecological soil quality [19]. They also discuss which kind of information is needed from the inventory to apply the respective indicator, which is considerably more than the simple information for occupation interventions. Milà i Canals et al. [19] also define a “transformation impact” which represents the difference between a reference state, where land use would not have been changed compared to the actual changes in the system under study. Taking into account the above-mentioned concepts, the comprehensive assessment of land use in LCA has to be based on three “dimensions” affected:
• • •
area, that is, the amount of surface used; time, that is, the duration of the occupation and transformation processes; quality, that is, description of land quality and the reference situation before, during, and after the land use.
Full application of impact assessment for land use in LCA studies, however, is still scarce because of two main reasons. One of these is the perception that “there is
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a contrast between the major environmental importance of land use and the lack of consensus of how to treat it methodologically” [19], a statement which obviously refers especially to the issue of how to describe the quality of land. Second, impact assessment for land use requires that detailed data on each of the relevant aspects have to be assembled on a regional scale in LCI. This kind of information is not yet readily available in databases for LCA and consequently has to be provided by labor-intensive investigations during an individual LCA study.
9.4 LCA Studies for Biobased Products: Major Findings and Insights
Early LCA studies on biobased products have been carried out already during the ’90s, covering “traditional” materials, for example, for packaging [22] as well as novel ones, like starch-based polymers [23]. Due to the large variety of biobased products, LCA studies may be quite diverse covering a broad scope of applications with often very tailored goal and scope. In order to gain some general insights, this chapter focuses in the first place on groups of biobased bulk or intermediate products which are of interest because of large production amounts and consequently high potential for saving GHG. The selected groups are biofuels, biopolymers, and biocomposites. Above this, there are studies focusing rather on a specific technology, notably biotechnological processes, whose results are included as well. As to biobased consumer products, a short survey on LCA studies from the building sector and for packaging is presented focusing on effects from the inclusion of the use phase rather than providing results for a specific material or product. 9.4.1 Biofuels
Driven by the boost of biofuels worldwide, a large number of LCA studies has been carried out on this group of biobased products. Biobased fuels are generally assessed in comparison to petrochemical fuels, where the reference products are gasoline, diesel, and natural gas. In addition, process chains for several biofuels are compared to each other, differing in technology and raw materials. Results are reported for fuel production only (“well-to-tank analysis”), or including fuel efficiency and emissions for vehicle use (“tank-to-wheel analysis”) – the first resulting in a functional unit per energy content of the fuel, whereas the latter is specified per distance of transportation. Also a functional unit per area of land used is reported frequently. Results of studies on biofuels are of interest also beyond the scope of the transportation sector, as compounds like ethanol or plant oils may also serve as intermediates to be used in future “green chemistry.” Biofuels comprise so-called first-generation and second-generation technologies. First-generation or conventional biofuels use part of a plant only. Technology has been applied since several years, so usually reliable data exist for LCA. In
9.4 LCA Studies for Biobased Products: Major Findings and Insights Table 9.2 First- and second-generation biofuels [17].
First generation
Second generation
Biodiesel, i.e., fatty acid methyl or ethyl ester from rapeseed, soybeans, sunflowers or palm oil; waste oils, e.g., from food
Bioethanol from lignocellulosic biomass
Pure plant oils, e.g., rapeseed oil, palm oil, soy oil Bioethanol from starch-containing crops (corn, wheat, potato)
Fischer–Tropsch diesel Dimethyl ether (DME) from lignocellulosic materials: waste wood, short-rotation woody crops (poplar, willow), switchgrass
Bioethanol from sugar (sugar beets, sugarcane)
contrast, second-generation biofuels make use of the full plant. They are based on either microbiological fermentation or thermochemical processes; technology is under development still or just about to enter the market; so often data for LCA are not fully available or have to be derived from lab experience. Table 9.2 presents an overview of biofuels from first- and second-generation technologies included in recent LCA studies. Due to the large number of existing literature, some comprehensive reviews of LCA studies on biofuels are available. In 2004, a report carried out by the German IFEU Institute on behalf of the Research Association for Combustion Engines (FVV), the Union for the Promotion of Oil and Protein plants, and the German association for Research on Automobile Technique surveyed 63 single studies dating from 1996 to 2004 [24]. As impact categories, energy as sum of nonrenewable primary energy use (NREU) and climate change are reported. Other impact categories are evaluated in a qualitative way due to the limited number of studies covering these categories. Assessments are presented for well-to-tank, tankto-wheel analysis, and also in terms of savings per hectare land. Figure 9.2 presents results for primary energy and GHG savings of biofuels compared to fossil counterparts per kilometer. All biofuels perform better compared to their fossil counterparts with the exception of liquefied hydrogen (LH) and gasified lignocellulose. There are, however, significant differences between different technology routes and for different feedstocks: savings are high for ethanol from sugarcane and sugar beet and for biogas from waste; they are low for ethanol from wheat, corn, and potatoes and for biodiesel from soy, coconut, and rapeseed (canola). Waste as a feedstock is favorable because no expenditures for farming have to be accounted for. However, large variations may result if alterative use of waste is taken into account which is indicated in Figure 9.2 by arrows with question marks. As to the impact categories acidification and eutrophication, distinct differences are found between cultivated biomass and waste biomass, which result from nitrogen emissions from agriculture; notably, this also implies the contribution of N2O (laughing gas) to GWP. For further impact
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Figure 9.2 Results of energy and greenhouse gas balances for biofuels and respective fossil counterparts in MJ-saved primary energy and g-saved CO2-equivalent per km [24].
categories, the authors state limited understanding of photo smog as well as knowledge gap for toxic emissions from vehicle use. A more recent survey comprehending the biofuels ethanol, methanol, biodiesel, and biogas has been commissioned in 2007 by Swiss federal administration (Bundesamt für Energie BFE, Bundesamt für Umwelt BAFU, Bundesamt für Landwirtschaft BLW) in 2007 [25]. It not only covers Swiss production but also biomass
9.4 LCA Studies for Biobased Products: Major Findings and Insights
100% Rape ME CH
Biodiesel
100% Rape ME RER 100% Palmoil ME MY 100% Soy ME US 100% Soy ME BR 100% Recycled plant oil ME CH 100% Recycled plant oil ME FR Methanol fixed bed CH Methanol fluidized bed CH
Alcohol
Ethanol grass CH Ethanol potatoes CH Ethanol sugar beets CH Ethanol whey CH Ethanol wood CH Ethanol sweet sorghum CN Ethanol rye RER Ethanol corn US
Methane
Ethanol sugarcane cane BR Methane grass biorefinery
Infrastructure Infrastructure
Methane manure
Cultivation Cultivation
Methane manure+cosubstrate Methane manure, optimized
Production Production
Methane manure+cosubstrate, optimized Methane biowaste
Transport Transport
Methane sewage sludge
Operation Operation
Fossil
Methane wood Diesel, low sulfur EURO3 Petrol, low sulfur EURO3 Natural gas, EURO3
–0.05
0.00
0.05
0.10
0.15
0.20
0.25
CO2-eq. (kg/pkm)
Figure 9.3 Comparison of greenhouse gas emissions in kg CO2-equivalents per km for biofuels and fossil fuels [25].
imported from main production regions worldwide. The state of technology taken into account is 2004. Results presented in Figure 9.3 for a functional unit per kilometer transport distance are dependent not only on the type of fuel but also on the kind and regional origin of the feedstock. High GWP is seen for ethanol made from potatoes, rye, and corn, and for biodiesel made from soya from Brazil and from rapeseed. The reason for this is the agricultural production, where low yields per hectare (e.g., potatoes) and high use of nitrogen fertilizer along with the emissions of N2O (nitrous oxide) for certain techniques of agriculture, for example, for corn from US, are the two major influencing factors. Generally, these results confirm those reported by Quirin et al. [24]. In the case of soy from Brazil, there is an additional factor: here, land transformation has been included, namely fire
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clearance of rainforest, which is supposed to take place for the production of soy. In contrast to the results presented by Quirin et al. [24], biodiesel performs worse compared to fossil diesel. Looking at further impact categories, not surprisingly energy consumption (reported as CED) correlates closely to GWP. Other impact categories perform different. As to photo-oxidant formation, mainly feedstock from tropical regions shows high impact because of either fire clearance or burning of dry leaves before harvesting. As to eutrophication, fertilizer use causes generally a higher impact compared to fossil fuels. The authors point out, however, that some examples – for example, sugarcane from Brazil – show that low fertilizer use and high yields per area due to favorable regional conditions allow low impact from eutrophication. The highest impact from ecotoxicology is due to fire clearance as well where acetone is the species contributing the most. Only biofuels produced from waste (e.g., sewage sludge or used cooking oil) perform better in all impact categories compared to fossil fuels. No alternative use of waste is included. As to the production process, the highest emissions are seen for biogas (methane). Here, emissions result from production technology, that is, emission of methane and N2O after fermentation and leakage of methane during conditioning. Technology for emission control exists but is not seen to be applied generally. As a subsuming result from both the surveys, the most important influence on environmental performance of biofuels as to GHG and to other impact categories is farming. Main impact comes from the land use change and fire clearance in tropical regions, whereas in temperate regions fertilizing and low yields are major contributing factors. The relevance of land use change on GHG has further become the focus of public because of a publication by Searchinger et al. in 2008, which concludes that GHG emission from biofuels produced in the US is higher than those of fossil fuels if accounting for indirect land use change effects [26]. Searchinger’s results have led to an ample discussion also including criticism as to his assumptions and methodological approaches, for example [27, 28]. Still it has become clear that indirect land use change is a major issue, and there is the need to broaden knowledge for a realistic assessment of the contribution of biofuels to climate mitigation. 9.4.2 Biopolymers
Although there has been a broad interest in biopolymers since many years and ample literature on technological processes exists, there is only a limited number of LCA studies on these groups of biobased products. A comprehensive survey has been carried out in 2005 in a study commissioned by European Commission’s Joint Research Centre, Institute for Prospective Technological Studies (JRC) on “Techno-economic Feasibility of Large-scale Production of Bio-based Polymers in Europe” [29]. The study covers existing and emerging technologies for several groups of biobased polymers, focusing exclusively on bulk chemical applications:
9.4 LCA Studies for Biobased Products: Major Findings and Insights
205
starch polymers, polylactic acid (PLA), other polyesters (PTT from biobased PDO, PBT from biobased BDO, PBS from biobased succinic acid), polyhydroxyalkanoates (PHAs), biobased polyurethane (PUR), cellulosic polymers, and emerging technologies for biobased polyamides (nylon). The environmental assessment is based on the evaluation of about 20 LCA and environmental studies, among these several Swiss and German ones. Results are presented for a functional unit of 1 kg of product. Impact categories covered are energy, climate change, and land use (in terms of ha/t polymer); only for modified starch polymers results for impact categories other than those were available. Data represent the present state of technology and were also used to forecast the production in 2010 and 2020. Figure 9.4 presents a tabular comparison of petrochemical and biobased polymers as to primary energy demand of production and GHG emissions. The savings from production of biobased polymers compared to petrochemical ones are found to be between 20 and 50 GJ/t polymer and 1.0–4.0 t CO2 eq/t polymer,
GHG emissions2) in kg CO2 eq./kg
Energy1) in MJ/kg
Reference for data on biobased polymer
Pchem. Polymer3)
Bio-based polymer
Energy savings
Pchem. Polymer3)
Bio-based polymer
Emission savings
Starch polymers Starch polymers + 15% PVOH Starch polymers + 52.5% PCL Starch polymers + 60% PCL 5) Starch polymers, mix today Starch polymers, long-term PLA - Year 1 PLA - Whey PLA - Biorefinery PLA, long-term PHA , fermentation PHB - Heyde, best case 6) PH(3B) ex glucose 7) PH(3A) ex soybean
76 76 76 76
25 25 48 52
51 52 28 24
4.8 4.8 4.8 4.8
1.1 1.7 3.4 3.6
3.7 3.1 1.4 1.2
76
41
2.8
54 40 29.2
4.8 4.8 4.8
4.0 ca. 3.0 1.89
76 76 76 76
81 66 59.2 50.2
35 50 22 36 47 50 -5 10 17 26
4.8
76 76 76
4.8 4.8 4.8 4.8
n/a 3.7 2.5 2.3
2.0 4.0 0.8 ca. 1.8 2.9 3.0 n/a 1.1 2.3 2.5
Estimated for this study Estimated for this study Vink et al, 2003 Vink et al, 2003 Vink et al, 2003 Estimated for this study Gerngross/Slater, 2000 Heyde, 1998 Akiyama et al., 2003 Akiyama et al., 2003
PTT (compared to PET)
77
65
13
5.5
4.6
4)
Patel et al., 1999 Patel et al., 1999 Patel et al., 1999 Patel et al., 1999
1.0
Estimated for this study
PTT, long term
10
1.0
Estimated for this study
PBT, long term
(10?)
(1.0?)
Estimated for this study
PBS, long term
(10?)
(1.0?)
Estimated for this study
PUR - Rigid PUR - Rigid, long term PUR - Flexible PUR - Flexible, long term Category "Other bio-based polyesters, 8) PUR and PA" , long term
99.5 103.0
77.8
21.7
62.9
20.0 40.0 40.0 25
5.9 6.0
5.0
0.9
Estimated for this study
4.4
1.0 1.6 1.5
Estimated for this study Estimated for this study Estimated for this study
2.0
Estimated for this study
Data printed in italics represent rough estimate. Data printed in bold are used for environmental assessment. Cradle-to-factory gate analysis. Without bio-based feedstock and bio-based energy byproducts used within the process. Cradle-to-grave analysis. Assuming full oxidation without any credits. 3) 50% LLDPE + 50% HDPE according to Boustead (1999). 4) Without petrochemical copolymers 5) Approximation: 20% pure starch polymers, 10% starch polymers with 15% petrochemical copolymers and 70% starch polymers with 52.5% petrochemical copolymers. 6) Case 9 in Akiyama et al. (2003) 7) Case 5 in Akiyama et al. (2003) 8) This group includes, apart from PUR and PA, all polyesters except for PLA, i.e. PHA, PTT, PBT, PBS, PBSA (and possibly others). 1)
2)
Figure 9.4 Specific energy use and GHG emissions in MJ and kg CO2-equivalents, respectively, per kg of polymer of biobased and petrochemical bulk polymers [29].
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respectively, which amounts to one- to two-thirds of the energy required for the production of petrobased polymers. The authors conclude that this is attributed mainly to the rather high energy requirement for the production of petrochemical polymers and that in consequence biobased polymers are very attractive in terms of specific energy and emissions savings. As one exception, PHA production by fermentation performs worse than its petrochemical counterpart – a result which is based on the publication of Gerngross and Slater in 2000 [30]. Other studies confirm this [31], but contradictory results are reported which conclude that energy consumption and GHG emission of PHA are lower than those of petrochemical polymers like HDPE [32, 33]. As to land use by the production of biopolymers, the required total amount of land in Europe is reported based on the calculated scenarios. The expectation is a rather modest land requirement which ranges from 1% to 5% of the total land. However, this is due to the modest expectation on the market share of biopolymers in the scenarios investigated which amount to a share of the EU production of petrochemical polymers between 1.25% and 2.5% by 2020. Some other publications report results for biopolymers including additional impact categories. Harding et al. [34] perform a cradle-to-gate LCA of PHB production taking into account GWP and 10 other impact categories. Findings are compared to the production of polypropylene (PP) and polyethylene (PE) and it is concluded that in all categories PHB is superior to PP. Energy requirements are reported to be significantly lower than for polyolefin production. On the other hand, acidification and eutrophication impacts are lower for PE than for PHB. Vinka et al. compare PLA to traditional petrochemical polymers of various kinds. For a functional unit of kg product, three impact categories are investigated: fossil fuel use, GWP, and water demand. Fossil energy and GWP show considerable reductions. Water is less or equal to other petrochemical products [35]. 9.4.3 Products from Biotechnological Processes
Another focus of LCA studies lies on a certain type of processes rather than a certain group of products. A special interest is on industrial biotechnology (“white biotechnology”), that is, the use of cells or enzymes as catalysts for the production of chemicals, commodities, as well as specialties. An OECD study in 2001 [36] investigated 21 case studies of industrial biotechnology indicating a reduction in environmental impacts compared to conventional technologies for all case studies. Scope of investigation, however, was limited to the processes itself and did not include a life-cycle approach. A study commissioned by the EU in 2006 on biotechnological production of bulk chemicals from renewable resources [37] investigates 21 bulk chemicals using LCA for environmental assessment. Systems boundary is cradle-to-gate based on a functional unit of 1 t of product. In addition, waste management is assessed where credits for energy recovery are accounted. As feedstock, crops for production
9.4 LCA Studies for Biobased Products: Major Findings and Insights
of fermentable sugar include maize and lignocellulose from Europe as well as sugarcane from tropical regions. For all products, savings are identified as to NREU, GWP, and other environmental impacts compared to petrochemical ones. For some novel processes, only limited or uncertain data are available. A publication by Hermann et al. subsumes data from the above-mentioned study and other data for the assessment of 10 biobased bulk chemicals produced by biotechnological processes [38]: 1,3-propanediol (PDO), acetic acid, acrylic acid, adipic acid, butanol, ethanol, lysine, lactic acid, PHAs, and succinic acid. Also five products are included produced from the fore-mentioned products: caprolactam, ethyl lactate, ethylene, PLA, polytrimethylene terephthalate (PTT). Functional unit is 1 t of product, systems boundary is set to include waste management. Impact assessment covers the categories of NREU, climate change, and land use in terms of land occupation. The technologies are assessed as to their current and long-term potential, that is, 20–30 years from now. Comparison is to petrochemical products based on conventional current technology, assuming that this technology is mature and no further development will take place. Figure 9.5 presents GHG and NREU savings for the products from biotechnological processes, which are identified for most products already for current technologies. As an exception, biotechnological production of acetic acid is found to provide no savings due to low productivity in fermentation and high energy demand in the downstream process of separating the azeotropic mixture of acetic acid from water. Results for savings of future technology (20–30 years from now) are estimated to be 25–35% higher than for current technology. Generally, it is
150% 120% 90%
30% Ethylene
Caprolactam
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Lysine
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Adipic acid
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PTT
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PLA
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EL
0% Lactic acid
GHG savings
60%
–90% –120% Today–Starch
Today–Cane
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Future–Cane
Figure 9.5 Greenhouse gas emission savings in ton CO2-equivalents per ton of IB chemical compared with their petrochemical counterparts for current and future technology cradle-tograve [38].
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found that the environmental impacts of the processes under study are influenced most by the assumptions for the fermentation process as to productivity, yield, and concentration. Inclusion of waste management has major influence on the results of assessment where savings of more than 100% compared to petrochemical products are calculated if energy credits from co-combustion of waste biomass are included. As to the raw materials, the lowest GHG emissions are found for sugarcane compared to lignocellulose and corn starch. Production of fermentable sugars from lignocellulose is assessed based on the assumption of future technology and for the example of corn stover. For this, land use efficiency in terms of CO2 savings per hectare is found to be superior compared to technologies using sugarcane. Some other recent publications investigate a limited number of case studies of industrial biotechnology. A study by Renner et al. concentrates on the methodological aspect of LCA for biotechnology, and covers the case studies for biotechnological production of indigo, penicillin, and PHAs [39]. As to the process chain, they find the highest environmental impact in the agricultural production of the raw materials. Hoppenheidt et al. report results for the production of vitamin B2 compared to the conventional production. Agricultural production is not included as both processes are based on glucose [40]. Based on a functional unit of 1 t of product, major reductions are found for the impact categories CED, GWP, acidification, and eutrophication. Rajni Hatti-Kaul et al. present results from LCA for microbial and enzymatic production of products from oleochemicals (hydrocarbons derived from vegetable oils) [41] and report advantages for the production of epoxidized and other oils. 9.4.4 Composites
Composites from natural fibers (e.g., hemp, flax, cellulose) and polymers are lightweight compounds with good mechanical properties which make them interesting for specific sectors of application, notably the transportation sector. Due to the specific application area, LCA of composites focuses not only on the materials but also on specific products for these application areas, covering the use phase of products. Wötzel et al. investigate an automotive side covering made of a composite from hemp fiber and epoxy-resin which is compared to a reference part from ABS resin [42]. The study is based on the ecoindicator 95 methodology for the impact assessment and covers the full life cycle. For the use phase, weight differences and resulting energy savings of a car are taken into account as well as two end-oflife options, deposition or incineration. Conclusions are small advantages for the hemp composite when restricting assessment on material production. These advantages grow considerably larger when including the use phase. Main impacts in the life cycle result from production of the epoxy resin, where the largest share is due to the energy consumption of the production process. The cultivation of hemp is considered ecologically insignificant. It is assumed to take place in Euro-
9.4 LCA Studies for Biobased Products: Major Findings and Insights
pean conditions with surplus production of food where no competition for land use occurs. Corbiere-Nicollier et al. investigate transport pallets made of composites from China reed fiber used as a substitute for glass fiber [43]. The crucial factor of the assessment is the lifetime of the pallets; the authors mention the need to optimize the process of fiber extraction in order to obtain a better material stiffness. For conventional pallets, a lifetime of 5 years is assumed. Environmental advantages for the transport pallets reinforced with China reed fiber are found if the pallet’s lifetime is greater than 3 years. These advantages result from the substitution of the glass fiber production, from the reduction of polypropylene, and from the reduced weight of the pallet. For end-of-life, incineration is the preferred option. Pietrini et al. assess an internal panel of a car made from PHB-based composites to the same part produced by conventional technology glass-fiber-filled polypropylene [44]. Impact categories are NREU and GWP. As fillers, sugarcane bagasse (SCB) and nanoscaled organophilic montmorillonite (OMMT) are used. Savings are reported for the PHB-based panel resulting mainly from the production phase. A lack of mechanical properties of PHB composites is reported but not reflected in the use phase. Two publications review some of the above-mentioned studies as well as older literature [45, 46]. As to the advantage of natural fiber composites compared to glass fiber composites, Joshi et al. identify the following main reasons: “(1) natural fiber production has lower environmental impacts compared to glass fiber production; (2) natural fiber composites have higher fiber content for equivalent performance, reducing more polluting base polymer content; (3) the light-weight natural fiber composites improve fuel efficiency and reduce emissions in the use phase of the component, especially in auto applications; and (4) end of life incineration of natural fibers results in recovered energy and carbon credits” [45]. Environmental advantages for fiber composites are also confirmed by further recent LCA studies for automotive parts [47, 48]. 9.4.5 Consumer Products
A large variety of consumer products based on renewable resources exists. Packaging has been the main issue of early LCA studies, an interest which has been induced by the debate on waste policy during the early ’90s and is still ongoing in the context of resource policy. Another prominent area of LCA is on building materials: the building sector as a whole is of high relevance for material and energy consumption and “sustainable” or “green” buildings is a topic of policy worldwide. Above that, housing is connected very closely to personal well-being and a major interest of consumers exists in health and environmental performance of materials for buildings. Deimling et al. [49] provide a survey on LCA studies for biobased products and evaluate the number of LCA studies for different groups; results point out that market volume and policy are the main drivers for LCA studies. In addition, the development of an ISO standard for environmental
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product declaration (EPD) based on LCA (the so-called Type III EPD) will give a further incentive for companies to perform LCA on specific products [50]. The following sections present short summaries on results for the product groups of packaging, building products, and lubricants, the latter being a large market for biobased products since several years as well. 9.4.5.1 Packaging Packaging comprises several types of products: transportation packaging, loose-fill packaging, bags and foils, as well as one-way cups and dishes [49]. As to all applications connected with transport, weight of the packaging as well as transportation distances are of major importance for results of studies, for example, Madival et al. [51]. General conclusions can only be drawn if assessment is restricted on the material where, for example, loose-fill packaging from corn starch is shown to have advantages compared to expanded polystyrol [49] or PLA drinking cups from corn are shown to perform better compared to polystyrene drinking cups [52]. For comparison of one-way to returnable packing, the number of cycles is a crucial issue. A study on bags for collection of compostable waste identifies an auxiliary process, that is, cleaning of sacks and provision of hot water and detergent, as the most influencing factor [49]. 9.4.5.2 Products for the Building Sector LCA in the building sector comprises materials as well as components and buildings as a whole. Groups of building products under assessment are notably insulation materials, floor panels, and windows made from renewables. Results from 74 studies are subsumed in [49]. Product groups do not show environmental advantages generally which is due to the use phase: lifetime and need for maintenance have decisive influence on results, where short lifetime and high maintenance requirements may outweigh the advantage of renewable resources and production process. Insulation materials are investigated by a large number of studies, where some favorable product types are identified, for example, insulation from flax compared to mineral wool, but contradictory results as to specific impact categories are reported. As to wood as construction material of houses, lower energy demand and GWP are advantageous compared to conventional building materials. 9.4.5.3 Lubricants Lubricants based on rapeseed oil have been in use already for long time and have been assessed by numerous LCA studies [49]. Compared to mineral oil, rapeseed oil performs better as to GWP but has disadvantages as to the impact categories of eutrophication and ozone depletion due to its agricultural cultivation. A generic advantage is biodegradability of rapeseed oil which decreases environmental impacts in case of incidents or leakage. As a major general feature, LCA studies point out the technical performance during the use phase: rapeseed oil is more sensitive to high pressure and temperature as mineral oil and it may contribute to corrosion of machinery; more frequent replacement during use as well as higher
9.5 Conclusions
maintenance of machinery are the consequences [53]. Although studies differ as to the amount of influence, they show that effects of use phase are significant for the assessment [49].
9.5 Conclusions
Despite the diversity of biobased products and the variety of goal and scope of LCA studies for different types of questions, some general insights can be derived. First, agriculture is of major importance in the life cycle of biobased products. Crucial issues are the choice of crop and its achievable yields as well as the farming practices which are applied. This holds true the most for biobased products where the process chain for production is short like biofuels, and for complex process chains a significant influence of agriculture is shown. Agriculture is also the stage which is responsible for important trade-offs between environmental impacts, notably trade-offs between carbon cycles and nitrogen cycles and the respective impact categories [54]. In order to minimize such trade-offs, most favorable regional conditions and careful optimization of farming conditions are required [26]. Second, comparison of different technology routes often shows a wide range of environmental performance. Choice of technology and optimization of processes is therefore a crucial issue as well. LCA studies show that in most cases, energy requirement of production processes is the major influencing factor. However, many studies state that up to now only limited data are available on impact categories not connected to energy use, for example, ecotoxicity. As to the use phase, additional aspects may become decisive, so here individual assessment and detailed evaluation of specific framework condition are required and general conclusions are only possible for homogenous groups of products. Third, waste management is important, which covers the management of waste from production processes as well as end-of-life of the biobased products itself. The energetic use of waste materials and products is accounted for as credits in LCA studies. This reflects the aspect of substitution of fossil carbon carriers for energetic use and supports the general insight that a double use is drawn by the successive material and energetic use of biomass. Compared to this, biodegradability of biobased products exhibits not a value in itself but advantages may rather be attributed to the specific use conditions of a product. A cross-cutting aspect is the procedural framework of LCA for the assessment of biobased studies. Numerous studies investigate the influence of methodological choices on the results of LCA, for example, as to the functional unit, allocation procedures, and differences in impact assessment, for example, Kim et al. [55], Landis et al. [56], Gnansounou et al. [57], Davis et al. [58]. Generally, surveys of LCA studies conclude that different studies cannot be compared directly due to different framework conditions, even if all apply to the ISO standards, for example [17, 49]. Consequently, a need for further standardization is perceived as
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to the application of LCA for decision support, notably if it is to support regulatory purposes [16, 59]. Summing up, results from LCA studies give broad evidence of the potentials of biobased products for the contribution to climate mitigation. On the other hand, they also point to major caveat for strategies of biomass use. In particular, it becomes clear that if the assumption of a “steady-state” agriculture is wrong and broad land use change takes place, even the very advantage of GHG savings might be jeopardized. Obviously, the most crucial issue for large-scale use of biobased products in general is the limited amount of land and the competition of uses, where the ongoing debate on the competition of land for food and biofuels is one most prominent example [60]. Further understanding of the dynamics of land use change is needed by incorporating economic modeling in LCA [61]. Modeling of carbon flows in economy may give important insights on competing demand for biomass and land [62]. As to technologies, optimization in all stages of the process chain is required. It is not only the substitution of fossil resources by renewable resources on its own, which provides advantages, but also the substitution of energy-intensive production routes of petrobased chemistry. And last but not the least, cascade use of biobased products should be a paradigm for enhancing efficiency. The overall challenge for the strategies on biobased products will be to make use of limited land and limited amount of biomass in the most efficient way. LCA may contribute to this by comprehensive insights on favorable options as to specific technologies as well as to the management strategies for biomass in general.
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von nachwachsenden Rohstoffen bei einer stofflichen Nutzung. Auftraggeber: Fachagentur nachwachsende Rohstoffe e.V., FKZ 114-50.10.0236/06-E. Edited by PE INTERNATIONAL GmbH. PE INTERNATIONAL GmbH. Stuttgart. Online available: http://www.novainstitut.de/news-images/20080717-02/ Oekologische_Betrachtung_stoffliche_ Nutzung_nR-1.pdf. Schmincke, E. and Grahl, B. (2006) Umwelteigenschaften von Produkten. Die Rolle der Ökobilanz in ISO Typ III Umweltdeklarationen. Umweltwissenschaften und SchadstoffForschung, 18 (3), 185–192. Madival, S., Auras, R., Singh, S.P., and Narayan, R. (2009) Assessment of the environmental profile of PLA, PET and PS clamshell containers using LCA methodology. J. Cleaner Prod., 17 (13), 1183–1194. Uihlein, A., Ehrenberger, S., and Schebek, L. (2008) Utilisation options of renewable resources: a life cycle assessment of selected products. J. Cleaner Prod., 16, 1306–1320. McManus, M.C., Hammond, G.P., and Burrows, C.R. (2004) Life-cycle assessment of mineral and rapeseed oil in mobile hydraulic systems. J. Ind. Ecol., 7 (3–4), 163–177. Miller, S.A., Landis, A., and Theis, T.L. (2007) Environmental trade-offs of biobased production. Environ. Sci. Technol., 41, 5176–5192. Kim, S. and Dale, B.E. (2006) Ethanol fuels: E10 or E85 – life cycle perspectives. Int. J. LCA, 11 (2), 117–121. Landis, A.E. and Theis, T.L. (2008) Comparison of life cycle impact assessment tools in the case of biofuels. IEEE International Symposium on Electronics and the Environment. (ISEE 2008, San Francisco, CA, 19–22 May 2008). Online available: http:// ieeexplore.ieee.org/servlet/ opac?punumber=4555641. Gnansounou, E., Dauriat, A., Panichelli, L., and Villegas, J. (2008) Energy and greenhouse gas balances of biofuels: biases induced by LCA modelling choices. J. Sci. Ind. Res., 67 (11), 885–897.
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9 Life-Cycle Analysis of Biobased Products 58 Davis, S.C., Anderson-Teixeira, K.J., and DeLucia, E.H. (2009) Life-cycle analysis and the ecology of biofuels. Trends Plant Sci., 14 (3), 140–146. Online available: http://www.life.illinois.edu/delucia/ Davis%20Life%20Cycle.pdf. 59 Liska, A.J. and Cassman, K.G. (2008) Towards standardization of life-cycle metrics for biofuels: greenhouse gas emissions mitigation and net energy yield. J. Biobased Mater. Bioenergy, 2, 187–203.
60 Young, A.L. (2009) Finding the balance between food and biofuels. Environ. Sci. Pollut Res., 16, 117–119. 61 Kløverpris, J., Wenzel, H., and Nielsen, P. (2008) Life cycle inventory modelling of land use induced by crop consumption. Int. J. LCA, 13 (1), 13–21. 62 Uihlein, A., Poganietz, W.R., and Schebek, L. (2006) Carbon flows and carbon use in the German anthroposphere: an inventory. Resour. Conserv. Recycling, 46, 410–429.
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For different reasons, there is a rising interest in the area of renewable resources over the last few years. On the one hand, there is a widespread perception that a competitive industrial production for the future must be affected by sustainability and consequently worldwide political incentives and regulations in favor of renewable resources are on the agenda. On the other hand, it is an accepted certainty that oil, coal, and natural gas are exhaustible resources with an undoubtedly increasing price trend in the long term. For the agricultural sector, the hope of decreasing dependency on the food markets and new additional income opportunities are important driving factors. For the industry, a change in the industrial raw material basis toward renewable resources offers the way to new products, new business models, and in the end to more sustainability – so the doubtlessly attractive vision. As discussed in Chapter 1, the aim of this book was to highlight all the areas that have to be regarded to realize the vision of a “biobased economy” as a sustainable industrial future based on renewable resources often is termed. The subject of the chapters was inspired by the scientific framework and the business conditions with an influence on the development of a biobased economy. Let us recapitulate the arguments from the specialist. The basis of every industrial activity relying on renewable resources is the plants in the fields: Chapter 2 highlights the various possibilities which plants offer as production systems of dedicated products starting with already marketed commodities like sugar, starch, cellulose, and oils and end up with fine chemicals, drugs, and plant-made pharmaceuticals. Industry, for example, the chemical industry, needs raw materials tailored specifically for defined needs. To develop these kinds of raw materials research is necessary. Plant breeding, biotechnology, and genetic engineering all hold possibilities to optimize yields and achieve the desired quality of the plants. The different technologies for specific plant breeding including genetic engineering are introduced. Industry, on the other hand, needs to invent and develop methods for processing renewable resources – another field for future research. The resume of Chapter 2 discusses that plants offer a lot of potential as suppliers of customized renewable
Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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raw materials, but challenges not only in the scientific area but also in the field of acceptance have to be met. Many products made from renewable resources have already entered the market and in future their number could grow significantly. But do we have enough land to produce the required amounts of renewable resources? Chapter 3 investigates this question. One assumption for a comprehensive use of renewable raw materials in industry is the increase in yield and productivity in the agricultural sector. But even if these can be realized – so the conclusion of the chapter – it is unlikely that agricultural products for industrial use will completely replace fossil resources, which is especially due to steadily increasing worldwide population. Renewable raw materials – so the summarizing outlook – may find widespread use in certain market sectors. Agriculture will be one of the many contributors to sustainable industrial production in the future. Renewable resources are agricultural and forestry products which are being put to nonfood uses. As the field of renewable resources is, like any other new technology, still subject to uncertainties, it is not yet clear how value chains will look like and how the logistics for renewable raw materials can be organized in an optimal manner. Chapter 4 points out that process chains based on renewables differ from their fossil counterparts in many aspects. First of all, renewable resources grow distributed in the environment; they have to be harvested, transported, and collected. Long-distance transports are disadvantageous because of the low density of renewables. Facility location planning, therefore, is an important issue. A possible scenario is that small factories are needed which can be supplied from the immediate environment. From the engineering aspect, this can be a disadvantage because the effects of “economy of scale” for large production facilities cannot be realized. The most promising options have to be identified from a technological and a logistical point of view and a lot of hints are given in this chapter. Biotechnology per se is dependent on renewables. The biotechnology industry makes use of renewable resources such as sugar or starch as feedstocks for fermentation processes. With the help of microorganisms and cell cultures, a great variety of different products is produced today, for example, amino acids, organic acids, vitamins, biopolymers, biopharmaceuticals, and biofuels. Chapter 5 presents an overview and discusses the technological developments in industrial biotechnology. One of the main aims is to discover raw materials, which are not in competition with the food and feed area and which can readily be applied for fermentation processes. Lignocellulosic materials have been identified as such a feedstock and many efforts are made to develop technologies to enable their application. Biorefineries are among the key areas for a successful industrial application of renewable resources. In concept, biorefineries are similar to petroleum refineries; however, biorefineries use renewables instead of petroleum to produce transportation fuels and chemicals. Biorefineries can employ various combinations of feedstocks and conversion technologies to produce a variety of products. The renewable feedstocks can be of various kinds of grain, energy crops such as corn, switchgrass, miscanthus, willow, and poplar, and agricultural, forest, and industrial residues
10 Conclusion
such as bagasse, stover, straws, forest thinnings, sawdust, and paper mill waste. This variety allows biorefineries to be spread into different geographical regions, but it also requires different technological approaches. Chapter 6 elucidates different biorefinery concepts and shows different possible products. Economic and production advantages increase with the level of integration in the biorefinery – it is one of the conclusions drawn in this chapter. This means that the more competitive a biorefinery is the more products it is able to produce from its feedstock. The agricultural sector would strongly benefit from the successful development of biorefineries because farmers would be the suppliers of the feedstock and could be able to generate an additional income. An increase in the industrial use of renewable raw materials, therefore, can offer a secured future for rural areas, which today often suffer from unemployment and low attractiveness for industry as well as for the younger population. These facts are the reason why the biorefinery concept receives a strong support by politicians and other stakeholders and even among the population of rural areas, as is pointed out in Chapter 7. If suitable technologies can be developed, renewable resources, which were of central importance with respect to the economy and agricultural policy before the Industrial Revolution, could gain more significance in our modern society with positive effects on agriculture, environment, and the economy. Currently, markets for bioproducts are wide-ranging, including polymers, lubricants, solvents, adhesives, herbicides, and pharmaceuticals and their production volume is estimated at several million tons per year. Total production in these markets is in the hundreds of millions of tons; therefore, the growth opportunities for biobased products are enormous – so the market analysis in Chapter 8. While bioproducts have already penetrated most of these markets to some extent, new products and technologies are emerging with the potential to further enhance performance, cost-competitiveness, and market share, so the optimistic outlook. A significant advantage of renewable resources lies in their contribution to the conservation of finite fossil resources. It is also important to note that the use of renewable resources is largely CO2-neutral, that is, CO2 emissions through combustion or bioconversion do not exceed the quantities which were absorbed during the growing process of the plant. There is no additional greenhouse effect, and life cycles are closed. Thus, agricultural or forestry raw materials (e.g., wood, plant oils, starch, etc.) can substitute fossil resources like mineral oil and coal in an environmentally benign way. Life cycle analysis (LCA) of biobased products is introduced in Chapter 9. Despite the wide variety of biobased products and the differences of goal and scope of LCA studies for different types of questions, some general insights can be derived. First, agriculture is of major importance in the life cycle of biobased products. The result of an LCA for a distinct product is strongly influenced by the kind of renewable feedstock chosen for its production process. Second, comparison of different technology routes often shows a wide range of environmental performance. Third, waste management is an important factor with great influence on the LCA result. Waste management covers the
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treatment or recycling of waste from production processes and end-of-life of the biobased products itself. To summarize, the editors and the authors of the various contributions address the vision of a biobased economy. Due to the wide range of different issues, for example, plant biotechnology, agricultural and forestry products, bioprocesses associated with chemical technology, bioproducts, biorefineries, and LCA, we expect that this book will be of great interest to biologists, chemists, and engineers in the industry, researchers in academia and industry, governmental institutes, students, and educators in chemical- and bioengineering, chemistry, biology, and environmental engineering.
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Index a
b
acetic acid 207, 208 acid hydrolysis 137, 138 acidification 197, 201 adjacency matrices 156, 158 agricultural production – chemical industry 44, 45 – current production capacity 36–40 – future prospects 43, 44, 218 – historical and projected demands 33, 34, 36–44 – increasing availability of renewable raw materials 43 – increasing production capacity 40–43 – life cycle analysis 188, 211 – logistics 71–73 – petrochemical production capacity 33, 34 – potential raw materials 34, 35 – scope for substitution 35, 36 – socioeconomic factors 143, 144 – traditional raw materials 34 – value chains 100–104 agricultural sector model (ASM) 151 algal feedstocks – biorefineries 127–129 – logistics 68, 69 – value chains 115–117 alkaloids 21–23 alkenes 104 amino acids 18 amylopectin 16 analytic modeling methodologies 150–155 animal fats 105 areas of protection (AoP) 194 artificial fertilizers 40, 41 artimisin 20 ASM, see agricultural sector model aspartic acid 131
bacterial nitrogen fixation 8 bagasse, see sugarcane bagasse barley feedstocks 63 benzene 139, 140 benzylisoquinoline 21, 22 Bergius method 137 bio-oil 138 bioaccumulation 41, 42 biobased economies 5, 217 biobased products – classification 172, 173 – conversion technologies 171, 172 – current status 173, 174 – definition 170, 171 – global production 171, 172 – life cycle analysis 196–211, 219, 220 – lubricants 177–179 – market analysis 169–186 – outlook and perspectives 182–184 – polymers 174–177 – solvents 179, 180 – surfactants 180–182 biobutanol 125 biochar 138 biochemical products 173 biodegradable polymers 134, 175–177 biodiesel – agricultural production 35, 36 – biorefineries 121, 125–127 – current and future outlook 125–127 – life cycle analysis 200–204 bioethanol – agricultural production 42, 43 – biorefineries 121, 123, 124, 136 – current and future outlook 123, 124 – life cycle analysis 200–204 – value chains 104, 107–110
Renewable Raw Materials: New Feedstocks for the Chemical Industry, First Edition. Edited by Roland Ulber, Dieter Sell, Thomas Hirth. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2011 by Wiley-VCH Verlag GmbH & Co. KGaA.
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Index biofuels – biorefineries 121–129, 138, 139 – current and future outlook 122–129 – life cycle analysis 200–204 – logistics 49, 54, 76, 77 biogas 204 biogenic residues 67, 68 Biomass Research and Development Act 173 bioreactors 7–32 – amino acids 18 – cellulose 12, 13 – chemical industry 7–17 – commodity production 8, 9 – fatty acids 9–12, 14, 18, 19 – fine chemicals and drugs 17–22 – genetically modified plants 7, 15–17 – methodologies for PMP production 26–28 – monoclonal antibodies 25 – natural and synthetic rubbers 12 – paper industry 13–15 – plant cell cultures 17 – plant-made pharmaceuticals 22–28 – plant protection 19 – polyphenols and resveratrol 22 – production problems 9–12 – small molecule drugs 7, 19–22 – starch-producing feedstocks 15, 16 – sugar-producing feedstocks 16, 17 – terpenoids 17, 18 – vaccines 24, 25 biorefineries 121–141 – agents and stakeholders 155–165 – agricultural production 36 – analytic and systemic modeling methodologies 150–155 – aspartic acid 131 – biobutanol 125 – biodiesel 121, 125–127 – bioethanol 121, 123, 124, 136 – biofuels 121–129, 138–139 – cellulose hydrolysis 136–138 – chemical industry 121, 127, 129–134, 136, 139 – clean technologies 134–138 – current and future outlook 122–129, 218, 219 – feedstocks 121, 122 – glycerol 127, 133, 134 – historical and projected demands 2–5 – levulinic acid 132 – logistics 49, 76, 77 – market analysis 183
– – – – – – – – –
microalgae 127–129 models of production 146–150 plant size 139 separation technologies 134, 135 socioeconomic factors 144, 146–165 sorbitol acid 132, 133 subsidies 163, 165 succinic acid 129–131 supercritical carbon dioxide extraction 135, 136 – thermochemical processing 138 – value chains 107 biotechnological processes 206–208 bisphenol A (BPA) 132 BREW project 34, 35, 98, 99
c C1 carbonic compounds 1, 3, 4 canola, see rapeseed feedstocks carbohydrate economies 117 carbon dioxide – biorefineries 135, 136 – historical and projected demands 5, 219 – life cycle analysis 187, 197 – value chains 114 carbon flow modeling 212 carbon funding mechanisms 148 cardboard, see paper industry carotinoids 19 catalysis technologies 169, 170 category indicators 192, 193 CDM, see clean development mechanism CED, see cumulative energy demand cell cultures 4, 7 cellulose – biobased products 172, 176 – bioreactors 12–14 – biorefineries 136–138 – logistics 63–65 – value chains 110, 111 – see also hemicelluloses; lignocellulose centrality 154, 160, 161 cereal crop feedstocks – agricultural production 37, 38 – bioreactors 15, 16 CGE, see computable general equilibrium characterization model 193, 194 chemical industry – agricultural production 44, 45 – bioreactors 7–22 – biorefineries 121, 127, 129–134, 136, 139 – cellulose 12, 13 – commodity production 8, 9 – cost estimation procedures 102–104
Index – fine chemicals and drugs 17–22 – historical and projected demands 3, 4 – life cycle analysis 204–206 – market analysis 169, 170 – natural and synthetic rubbers 12 – paper industry 13–15 – production problems 9–12 – starch-producing feedstocks 15, 16 – sugar-producing feedstocks 16, 17 – value chains 95–98, 100–104 clean development mechanism (CDM) 148, 149 clean technologies 134–139, 183 climatic factors 50, 51 coconut oil 34, 57 cognitive maps 152–155, 157–159, 165, 166 combinatorial biosynthesis 21, 22 Common Agricultural Policy (CAP) 40, 143, 144, 184 communications technology 70 community factors 145 competing technologies – economic factors 1, 2 – logistics 86, 87, 89, 90 – socioeconomic factors 163 – value chains 99 complexity index 154 composites 208, 209 computable general equilibrium (CGE) model 151 conditioning processes 73–75 construction industry – bioreactors 16 – life cycle analysis 210 – market analysis 169 consumer products 209–211 contractors 70 coproduct generation 197 corn, see maize feedstocks cost-competition 99 cost estimation procedures 102–104 cotton feedstocks – agricultural production 34 – bioreactors 13 cottonseed oil 56, 57 crop protection 72, 73 crop residues 67 crop rotation 72, 73 cross-cutting 211, 212 crude oil, see petrochemicals crude tall oil (CTO) 68 cultivation logistics 52, 72, 73, 75 cumulative energy demand (CED) 195
cut-off criteria 191 cyclodextrins 16 cysteine 18 cytochrome P450 21, 22 cytokines 26
d decoupling 84, 144 deforestation 42, 148 detergent industry 15, 16 developing economies 43, 44 DHA, see docosahexanoic acid direct substitution strategies 98 docosahexanoic acid (DHA) 115 Dutch Disease 147
e ecofactors 195, 196 ecoindicator 99, 195 economic factors, see socioeconomic factors economies of scale 82–84 economies of scope 85 elementary flows 190, 191 end-of-life phase 197, 211 energy crops 107, 108, 118 energy flow analysis 88 energy policy 145, 146, 166 environmental factors – agricultural production 42, 46 – biobased products 179, 184 – historical and projected demands 4, 5 – life cycle analysis 187, 188, 195–197, 201–206, 209–211 – logistics 87 – socioeconomic factors 144, 147, 148, 159 environmental product declarations (EPD) 209, 210 Environmental Protection Agency (USEPA) 73 enzyme-based processes – agricultural production 36 – biobased products 173, 183 – bioreactors 7, 8 – biorefineries 126, 127, 135–138 – historical and projected demands 4 – value chains 107, 110–113 EPA, see Environmental Protection Agency EPD, see environmental product declarations erucic acid 41, 55 ethyl lactate 180 ethylene 139, 140 European Climate Change Programme 174 eutrophication 197, 201, 204
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f facility location planning 85, 86 fast-growing energy crops 107 fat processing feedstocks 105 fatty acids – biobased products 178 – bioreactors 9–12, 14, 18, 19 – logistics 55–57 – value chains 115 fermentation – bioreactors 15, 16 – value chains 95–99, 112, 117, 118 fertilization processes 72, 73 fertilizers 40, 41 first-generation biofuels 200, 201 Fischer–Tropsch synthesis 172 flax oil 57 flex-fuel cars 123 forage grasses 66 forest residues 65, 66 forestry, see wood-based feedstocks fossil resources, see petrochemicals fructose sugars 58–60 functional approach to land use 199 functional competition strategies 98, 99 functional units 197 fuzzy cognitive maps (FCM) 145, 146, 152– 155, 165, 166
g gamma linoleic acid (GLA) 114 gasification technologies 138, 183 genetically modified plants (GMP) – agricultural production 39, 42 – bioreactors 7, 15, 16, 17, 217 – biorefineries 136–138 – historical and projected demands 4 – value chains 107 geographic dispersion 163, 164 geographic information systems (GIS) 88 GHG, see greenhouse gases GIS, see geographic information systems GLA, see gamma linoleic acid global model of production 146–150 global warming potential (GWP) 187, 201–210 glucose sugars – logistics 58–60, 62 – value chains 114, 115, 118 glucosinolate 55 glycerol – agricultural production 35 – bioreactors 9–12
– biorefineries 127, 133, 134 – value chains 105, 115 glycosyltransferases 28 GMP, see genetically modified plants grasses – logistics 66 – value chains 107 green plant residues 67 green polyethylene 139, 140 greenhouse gases (GHG) – historical and projected demands 5 – life cycle analysis 187, 197, 200, 202–208, 212 – market analysis 170, 174, 184 – socioeconomic factors 143, 144, 148 – value chains 114 grouping 193, 194 growth factors 26 GWP, see global warming potential
h Haber–Bosch process 8 harvesting logistics 52, 73–79, 86 health factors 147, 148 hemicelluloses – bioreactors 14 – logistics 58, 63 – value chains 110–112, 115, 135 herpes simplex virus (HSV) 25 heterogeneous catalysis 126 hierarchy index 154 HIV-specific antigens 24 HSV, see herpes simplex virus human growth factors 26 hydraulic fluids 179 hydrolytic processes 107, 110–113, 135–138
i IFECO, see integrated farm energy cogeneration ignorance 150–152 IMPACT2000+ 194, 195 in-degree 153, 154, 160, 161 in-situ-product-remove (ISPR) 112, 113 industrial starch 62, 63 industrial utilization chains, see logistics insulin 24–26 integrated assessment and planning methods 88, 89 integrated farm energy cogeneration (IFECO) 151 integrated process management 112, 113 integration logistics 85, 86 intermediate flows 191
Index International Standardization Organization (ISO) 189–195, 209, 210 irrigation 41, 72, 73 ISO, see International Standardization Organization isoprenes 9, 14 ISPR, see in-situ-product-remove
j Joint Research Centre (JRC) 204
k Karlsruhe Institute of Technology (KIT) 84 KDEL endoplasmic reticulum targeting signal 27, 28 key indicators 199 KIT see Karlsruhe Institute of Technology Kyoto Protocol 148, 149
l land use – functional approach 199 – future prospects 218 – life cycle analysis 198–200 – logistics 49, 51, 52, 66 – socioeconomic factors 143, 144 – value chains 113 latitude 51 LCA, see life cycle analysis LCI, see life cycle inventories LCIA, see life cycle impact assessment levulinic acid 132 LH, see liquefied hydrogen life cycle analysis (LCA) 187–216 – biobased products 196–211, 219, 220 – biofuels 200–204 – biotechnological processes 206–208 – characterization model 193, 194 – composites 208, 209 – construction industry 210 – consumer products 209–211 – databases and software 196 – general goals 188, 189 – general scheme 189, 190 – goal and scope definition 190 – historical and projected demands 5 – interpretation of results 196 – land use 198–200 – life cycle impact assessment 192–196, 199, 200 – life cycle inventories 190–192, 199, 200 – logistics 88 – lubricants 210, 211 – major findings and insights 200–211
– methodological framework 188–197 – packaging 210 – phases 189–196 – polymers 204–206 – practical approaches 194–196 – socioeconomic factors 151 life cycle impact assessment (LCIA) 192– 196, 199, 200 life cycle inventories (LCI) 190–192, 199, 200 lignocellulose – agricultural production 35, 42, 43 – biorefineries 123, 124, 130, 132, 135 – economic factors 1, 2 – historical and projected demands 1–3 – life cycle analysis 201 – logistics 58, 64–67, 84, 87, 218 – value chains 105, 107–114 lignosulfonates 121 limonene 18 D-limonene 180 linoleic acid – biobased products 178 – bioreactors 9 – logistics 55–57 – value chains 114 linolenic acid 178 linseed oil 57 lipids 115, 172 liquefied hydrogen (LH) 201 livestock manures 67, 68 local economic systems 156, 165 local model of production 146, 147, 149, 150 location planning 85, 86 logistics 49–94 – actors and stakeholders 69–71, 89 – agricultural production 71–73 – algal feedstocks 68, 69 – biogenic residues 67, 68 – biorefineries 49, 76, 77 – characterization of renewable raw materials 52–69 – competing technologies 86, 87, 89, 90 – cultivation 52, 72, 73, 75 – design and planning of logistic chains 82–89 – determining factors 50–71 – economies of scale 82–84 – harvesting 52, 73–79, 86 – historical and projected demands 4, 218 – integrated assessment and planning methods 88, 89 – land use 49, 51, 52, 66 – lignocellulose 58, 64–67, 84, 87
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Index – location planning 85, 86 – mobilization of renewable raw materials 69–71 – oilseed feedstocks 52–57 – operating in a natural environment 50–52 – plant size 82–84 – processing steps 71–82 – starch crop feedstocks 60–64 – storage 49, 81, 82 – sugar crop feedstocks 57–60 – transport processes 49, 79–81, 82–84, 86, 89 – wood-based feedstocks 64–66, 69–71, 75–79, 84, 87 low-cost carbon sources 115–117 lubricants – life cycle analysis 210, 211 – market analysis 177–179
mechanized harvesting chains 76–79 menthol 17, 18 methyl soyate 180 methyl tetrahydrofuran (MTHF) 132 microalgae 68, 69, 115–117, 127–129 microbial processes, see fermentation microbial single-cell oils 114–117 MIP, see Market Introduction Program MIPS, see material intensity per service unit molasses 57, 58 monoclonal antibodies (MAb) 25 MTHF, see methyl tetrahydrofuran multiattributive decision making (MADM) 89 multiattributive utility theory (MAUT) 89 multiattributive value theory (MAVT) 89 multicriteria decision making (MCDM) 89 multiple-phase/step harvesting 73, 74 municipal solid wastes 109
m
n
MAb, see monoclonal antibodies macroalgae 69 MADM, see multiattributive decision making magnoflorine 22 maize feedstocks – agricultural production 39 – biorefineries 134 – logistics 60–62 management operations 52 manures 67, 68 market analysis – agricultural production 38–40 – biobased products 169–186 – biorefineries 122 – classification of biobased products 172, 173 – conversion technologies 171, 172 – current status 173, 174 – definition of biobased products 170, 171 – global production 171, 172 – historical and projected demands 1–3, 5 – lubricants 177–179 – outlook and perspectives 182–184 – polymers 174–177 – solvents 179, 180 – surfactants 180–182 Market Introduction Program (MIP) 179 material flow analysis 88 material intensity per service unit (MIPS) 195 MAUT, see multiattributive utility theory MAVT, see multiattributive value theory MCDM, see multicriteria decision making
N-glycosylated proteins 28 naphtha crackers 3 natural fibers 208 natural pigments 121 natural rubbers (NR) 12 Nef protein 27 network analysis, see social network analysis network indices 156 new product strategies 100 nonrenewable energy use (NREU) 195, 201, 207–209 normalization 193, 194 novelty 150–152 NR, see natural rubbers NREU, see nonrenewable energy use
o oats feedstocks 64 occupation processes 198 oilseed feedstocks – agricultural production 36–38, 41 – biobased products 172 – bioreactors 9–12 – biorefineries 136 – logistics 52–57 – value chains 105 oleic acid 55–57 oleochemical feedstocks 180, 181 omega-hydroxy fatty acids 9, 12 OMMT, see organophilic montmorillonite one-phase/step harvesting 73, 74 operating costs 85 oral immune tolerance 24, 25
Index organophilic montmorillonite (OMMT) 209 out-degree 153, 154, 160, 161
p PAA, see polyaspartic acid packaging 210 palm oil 34 paper industry – agricultural production 34 – bioreactors 13–15 – logistics 62, 68, 87 – value chains 105, 106 pectins 63 pest resistance 42 pesticides 41, 42 petrochemicals – biorefineries 121, 122 – historical and projected demands 1, 2, 33, 34, 44 – life cycle analysis 202–206 – logistics 49 – market analysis 180, 181 – production capacity 33, 34 – value chains 97–104 PHA, see polyhydroxyalkanoate pharmaceuticals – bioreactors 7, 26–28 – biorefineries 127 – historical and projected demands 4 – market analysis 169 – see also plant-made pharmaceuticals photo-oxidants 204 photobioreactors 127–129 photosynthetic processes 183 pigments 121 PLA, see polylactic acid plant cell cultures 17 plant enzymes, see enzyme-based processes plant-made pharmaceuticals (PMP) – bioreactors 22–28, 217, 218 – biorefineries 121 – methodologies 26–28 – monoclonal antibodies 25 – vaccines 24, 25 plant protection 19 plant size 82–84 plastics 176, 177 PMP, see plant-made pharmaceuticals polyaspartic acid (PAA) 131 polyethylene (PE) 139, 140 – life cycle analysis 206 – market analysis 175 polyhydroxyalkanoate (PHA) 175, 176, 180, 205–208
polylactic acid (PLA) – agricultural production 36, 45 – biorefineries 133 – market analysis 174, 175 polymers – agricultural production 33, 36 – biorefineries 139, 140 – historical and projected demands 4 – life cycle analysis 204–206 – market analysis 174–177 polyphenols 22 polypropylene (PP) 206 polyurethanes 178 population growth 38, 39, 43–46 posttranslational modifications 28 potato feedstocks 15, 16, 62, 63 PP, see polypropylene precommercial thinning 75 pretreatments 110, 111 process flows 191 process technologies 169, 170 product flows 190 product oriented integration 85, 86 protein delivery 54, 55, 63 proven product strategies 100 public health factors 147, 148 public information 162, 163 punctual indices 156, 159 pyrethroids 19 pyrolysis technologies 138, 183
q quantitative trait loci (QTL)
20
r rail transport 80, 86 rapeseed feedstocks 36, 41, 55, 56 rapeseed methyl ester (RME) 55 recombinant proteins 26–28 recycling 44, 126 resveratrol 22 reticuline 22, 23 rhizomatous grasses 66 RME, see rapeseed methyl ester road transport 80, 86 root crops 74 rural development 144, 146–150, 155–165, 184 rye feedstocks 63, 64
s safflower oil 57 sawmilling residues 65, 66 SBA, see sorbitol acid
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Index scale economies 82–84 SCB, see sugarcane bagasse SCO, see single-cell oil scopolamine 21, 22 SCORE model 151 SEC, see size-exclusion chromatography second-generation biofuels 200, 201 second-generation feedstocks 105, 106 secondary metabolites 20 selective breeding 40, 41 sender variables 154, 159, 160 separation technologies 134, 135, 183 SETAC, see Society of Environmental Toxicology and Chemistry shavings 65, 66 shikimate pathway 8 shipping 80, 81 short rotation crops 66, 74 simultaneous saccharification and fermentation (SSF) 110 single-cell oil (SCO) 107, 114–117 size-exclusion chromatography (SEC) 134 small molecule drugs (SMD) 4, 7, 19–22 SNA, see social network analysis social network analysis (SNA) 153–155, 156–165 Society of Environmental Toxicology and Chemistry (SETAC) 189, 194–196 socioeconomic factors 143–168 – agents and stakeholders 145, 146, 155–165 – agricultural production 38–40, 42–44, 46, 143, 144 – analytic and systemic modeling methodologies 150–155 – biobased products 184 – biorefineries 123, 125, 126, 144, 146–165 – cost estimation procedures 102–104 – determinants 162–164 – effects and impacts 164, 165 – fuzzy cognitive maps 145, 146, 152–155, 165, 166 – historical and projected demands 1, 2, 4, 5, 219 – influential conditions 164, 165 – logistics 75, 82–84, 85, 87 – methodology review 150–152 – models of production 146–150 – novelty, uncertainty, ignorance and unpredictability 150–152 – research and development 159 – rural development 144, 146–150, 155–165
– theoretical framework 150–152 – value chains 100–104, 115–118 – see also market analysis soil conditions 51 soil degradation 148 solvents 179, 180 sorbitol acid (SBA) 132, 133 sorghum feedstocks 64 sowing processes 72 soybean feedstocks – agricultural production 36–39 – biobased products 178, 180 – logistics 52–55 spontaneous species 164 SR, see synthetic rubbers SSF, see simultaneous saccharification and fermentation stand establishment 75 STARBON, see starch-derived mesoporous solid acid starch crop feedstocks – agricultural production 43 – biobased products 172, 176 – bioreactors 15, 16 – logistics 60–64 – socioeconomic factors 143 – value chains 105, 118 starch-derived mesoporous solid acid (STARBON) 129–131 stem-like crops 73, 74 storage 49, 81, 82 straw feedstocks 67 subsidies 163, 165 succinic acid 129–131 sucrose sugars 57, 58–60, 114, 118 sugar beet 57, 58–60, 84 sugar crop feedstocks – agricultural production 37, 38 – biobased products 172 – bioreactors 16, 17 – biorefineries 123, 124, 132, 135 – logistics 57–60, 84 – value chains 105, 109, 115, 118 sugar-to-(thermal) polyaspartic acid (TPA) 131 sugarcane 57–59 sugarcane bagasse (SCB) 58, 123, 124, 135, 209 sulfite pulping 68 sunflower feedstocks 56 supercritical carbon dioxide extraction 135, 136 supply oriented integration 85, 86 surfactants 180–182
Index synthetic rubbers (SR) 12 systemic modeling methodologies
150–155
t tall oil fatty acids (TOFA) 68 tall oil rosin (TOR) 68 tending wood stands 75 terpenoids 17, 18 territory 156 textile industry 169 thermochemical processing 138 tillage 72 tobacco mosaic virus (TMV) 27 TOFA, see tall oil fatty acids topographic factors 51 TOR, see tall oil rosin TPA, see sugar-to-(thermal) polyaspartic acid transformation processes 198 transgenic Bt poplar trees 15 transgenic sugar beet 16 transmitter variables 159–161 transparency 70 transport processes 49, 79–81, 82–84, 86, 89 triglycerides 126–129 trypsinogen 27, 28 tuber crops 74 two-phase/step harvesting 74
u uncertainty 150–152 unpredictability 150–152 use phase 197 USEPA, see Environmental Protection Agency utilization chains, see logistics
v vaccines 24, 25 value chains 95–119 – advantages and constraints 108–111, 113, 115–117 – alkenes from petroleum and bioethanol 104 – bioethanol 104, 107–110 – biomass composition 111 – cost estimation procedures 102–104
– current situation 95–97 – feedstock and process technologies 100–104 – fermentation 95–99, 112 – hydrolytic processes 107, 110–113 – lignocellulose 105, 107–114 – main products, substrates and raw materials 95–97 – pretreatments 110, 111 – production costs of chemicals 100–104 – research and development potential 112–117 – single-cell oil 107, 114–117 – strategies 98–100 – substrate constraints 110, 113 – white biotechnology 97–100, 105–107, 117, 118 vegetable oils 109, 177 vinasse 58 vitamins 18, 19
w waste management 211 waste residues 115, 164, 165 water availability 41 weather conditions 50, 51 weighting 193, 194 wheat feedstocks 63 white biotechnology 97–100, 105–107, 117, 118, 169, 170 wood residues 65, 66, 77–79 wood-based feedstocks – agricultural production 34, 35 – biobased products 172 – historical and projected demands 1–3 – logistics 64–66, 69–71, 75–79, 84, 87 – socioeconomic factors 144 – value chains 105, 106, 108, 109
x xanthophylls xylose 115
134
z zein 134 zero-cost carbon sources 114–117
229