Biofuels and Bioenergy

About the EditorsJohn Love and John A. Bryant, Biosciences, College Of Life and Environmental Sciences, University of Exeter, UK

• List of Contributors xiiiPreface xvList of Abbreviations xix1 Biofuels: The Back Story 1John A. Bryant and John LoveSummary 11.1 Introduction 11.2 Some history 11.2.1 Wood and charcoal 11.2.2 Dung as fuel 21.2.3 Oils and fats 21.2.4 Peat 31.3 Fossil fuels 41.3.1 Coal 41.3.2 Petroleum Oil 51.3.3 Natural gas 61.4 Fossil fuels and Carbon Dioxide 61.4.1 The Club of Rome 61.4.2 Climate change 71.5 Alternative Energy Sources 91.5.1 Introduction 91.5.2 Environmental Energy Sources 91.5.3 Nuclear power 151.5.4 Hydrogen 171.6 Biofuels 18Selected references and suggestions for further reading 192 Biofuels in Operation 21Lionel ClarkeSummary 212.1 Fuels for Transport 212.2 Future Trends in Fuels Requirements and Technology 242.3 Engines and Fuels – Progress vs Inertia 262.4 Engine Constraints, Fuel Specifications and Enhanced Performance 282.5 Biofuels – Implications and Opportunities 322.5.1 Introduction 322.5.2 Ethanol 322.5.3 Biodiesel 332.6 Advanced Biofuels as Alternatives to Ethanol and FAME 372.7 Biofuels for Aviation; ‘Biojet’ 402.8 Impact of Future Trends in Engine Design on Retail Biofuels 422.9 Conclusion 43Selected References and Suggestions for Further Reading 433 Anaerobic Digestion 45John Bombardiere and David A. StaffordSummary 453.1 History and Development of Anaerobic Digestion 453.1.1 Introduction 453.1.2 Mixtures of Micro‐Organisms 463.2 Anaerobic Digestion: The Process 473.2.1 General Biochemistry 473.2.2 Design Types 473.2.3 Complete Mix Design 473.2.4 Plug Flow Digesters 483.2.5 High Dry Solids AD Systems 493.2.6 Upflow Anaerobic Sludge Blanket (UASB) 503.2.7 Anaerobic Filters 503.3 Commercial applications and benefits 513.3.1 In the United Kingdom 513.3.2 In the USA 513.3.3 In Germany 523.3.4 Overall Benefits 523.4 Ethanol Production Linked with Anaerobic Digestion 533.5 Financial and Economic Aspects 543.6 UK and US Government Policies and Anaerobic Digestion – an overview 553.7 Concluding Comments 56Selected References and Suggestions for Further Reading 574 Plant Cell Wall Polymers 59Stephen C. FrySummary 594.1 Nature and Biological Roles of Primary and Secondary Cell Walls 594.2 Polysaccharide Composition of Primary and Secondary Cell Walls 604.2.1 Typical dicots 604.2.2 Differences in Certain Dicots 674.2.3 Differences in Monocots 674.2.4 Differences in Gymnosperms 684.2.5 Differences in Non‐seed Land‐plants 684.2.6 Differences in Charophytes 684.3 Post‐synthetic Modification of Cell‐wall Polysaccharides 704.3.1 C ross‐linking of cell‐wall polysaccharides 704.3.2 Hydrolysis of Cell‐wall Polysaccharides 724.3.3 ‘Cutting and Pasting’ (Transglycosylation) of Cell‐wall Polysaccharide Chains 754.4 Polysaccharide Biosynthesis 774.4.1 General Features 774.4.2 At the Plasma Membrane 774.4.3 In the Golgi System 784.4.4 Delivering the Precursors – sugar Nucleotides 794.5 Non‐polysaccharide Components of the Plant Cell Wall 804.5.1 Extensins and Other (Glyco)Proteins 804.5.2 Polyesters 834.5.3 Lignin 844.5.4 Silica 844.6 Conclusions 85Acknowledgements 85Appendix 85Selected References and Suggestions for Further Reading 855 Ethanol Production from Renewable Lignocellulosic Biomass 89Leah M. Brown, Gary M. Hawkins and Joy Doran-PetersonSummary 895.1 Brief History of Fuel‐Ethanol Production 895.2 Ethanol Production from Sugar Cane and Corn 925.3 Lignocellulosic Biomass as Feedstocks for Ethanol Production 935.3.1 The Organisms 935.3.2 Lignocellulosic Biomass 965.3.3 Pretreatment of Lignocellulosic Biomass 995.3.4 Effect of Inhibitory Compounds on Fermenting Microorganisms 1005.4 Summary 1025.5 Examples of Commercial Scale Cellulosic Ethanol Plants 1035.5.1 Beta Renewables/Biochemtex Commercial Cellulosic Ethanol Plants in Italy, Brazil, USA and Slovak Republic 1035.5.2 Poet‐DSM ‘Project Liberty’ – First Commercial Cellulosic Ethanol Plant in the USA 1035.5.3 Abengoa Hugoton, Kansas commercial plant and MSW to ethanol Demonstration Plant, Salamanca 103Selected References, Suggestions for Further Reading and Useful Websites 1046 Fatty Acids, Triacylglycerols and Biodiesel 105John A. BryantSummary 1056.1 Introduction 1056.2 Synthesis of Triacylglycerol 1076.2.1 The Metabolic Pathway 1076.2.2 Potential for Manipulation 1106.3 Productivity 1116.4 Sustainability 1146.5 More Recently Exploited and Novel Sources of Lipids for Biofuels 1146.5.1 Higher Plants 1146.5.2 Algae 1156.5.3 Prokaryotic Organisms 1166.6 Concluding Remarks 117Selected References and Suggestions for Further Reading 1177 Development of Miscanthus as a Bioenergy Crop 119John Clifton‐Brown, Jon McCalmont and Astley HastingsSummary 1197.1 Introduction 1197.2 Developing Commercial Interest 1227.3 Greenhouse Gas Mitigation Potential 1277.4 Perspectives for ‘now’ and for the Future 128Selected References and Suggestions for Further Reading 1298 Mangrove Palm, Nypa fruticans: ‘3‐in‐1’ Tree for Integrated Food/Fuel and Eco‐Services 133C.B. Jamieson, R.D. Lasco and E.T. RascoSummary 1338.1 Introduction: the ‘Food vs Fuel’ and ‘ILUC’ Debates 1338.2 Integrated Food‐Energy Systems (IFES): a Potential Solution 1348.2.1 Main Features of IFES 1348.2.2 Baseline Productivity 1368.3 Land use: the Importance of Forest Ecosystem Services 1378.4 Sugar Palms: Highly Productive Multi‐Purpose Trees 1388.5 Nipa (Nipa fruticans): a Mangrove Sugar Palm with Great Promise 1408.6 Conclusion 141Selected References and Suggestions for Further Reading 1419 The Use of Cyanobacteria for Biofuel Production 143David J. Lea‐Smith and Christopher J. HoweSummary 1439.1 Essential Aspects of Cyanobacterial Biology 1439.1.1 General Features 1439.1.2 Photosynthesis and Carbon Dioxide Fixation 1449.1.3 Nitrogen Fixation 1469.2 Commercial Products Currently Derived from Cyanobacteria 1469.3 Cyanobacteria Culture 1479.4 Cyanobacterial Genomes and Genetic Modification for Biofuel Production 1489.5 Industrial Production of Biofuels from Cyanobacteria 1529.6 Conclusion 154Selected References and Suggestions for Further Reading 15410 Third‐Generation Biofuels from the Microalga, Botryococcus braunii 157Charlotte Cook, Chappandra Dayananda, Richard K. Tennant and John LoveSummary 15710.1 Botryococcus braunii 15710.2 Microbial Interactions 16010.3 Botryococcus braunii as a Production Platform for Biofuels orChemicals 16110.3.1 Hydrocarbons, Lipids and Sugars 16110.3.2 Controlling and Enhancing Productivity 16310.3.3 Alternative Culture Systems 16510.3.4 Harvesting Botryococcus Biomass and Hydrocarbons 16610.3.5 Processing Botryococcus into an Alternative Fuel 16610.4 Improving Botryococcus 16710.5 Future Prospects and Conclusion 169Selected References and Suggestions of Further Reading 17011 Strain Selection Strategies for Improvement of Algal Biofuel Feedstocks 173Leyla T. Hathwaik and John C. CushmanSummary 17311.1 Introduction 17311.2 Lipids in Microalgae 17411.3 Starch in Microalgae 17511.4 Metabolic Interconnection Between Lipid and Starch Biosynthesis 17611.5 Strategies for the Selection of Microalgae Strains with Enhanced Biofuel Feedstock Traits 17711.5.1 Manipulation of Growth Conditions 17711.5.2 Genetic Mutagenesis 17711.5.3 F low Cytometry 17811.5.4 Fluorescence‐Activated Cell Sorting 18111.5.5 Buoyant Density Centrifugation 18311.6 Conclusions 185Acknowledgements 185Selected References and Suggestions for Further Reading 18512 Algal Cultivation Technologies 191Alessandro Marco Lizzul and Michael J. AllenSummary 19112.1 Introduction 19112.2 Lighting 19212.3 Mixing 19412.4 Control Systems and Construction Materials 19612.5 Algal Production Systems at Laboratory Scale 19712.6 Algal Production in Open Systems 19812.6.1 Pond‐Based Systems 19812.6.2 Membrane Reactors 20012.7 Algal production in Closed Systems 20112.7.1 Introduction 20112.7.2 Plate or Panel Based Systems 20112.7.3 Horizontal Tubular Systems 20312.7.4 Bubble Columns 20512.7.5 Airlift Reactors 20712.8 Concluding Comments 209Selected References and Suggestions for Further Reading 20913 Biofuels from Macroalgal Biomass 213Jessica AdamsSummary 21313.1 Macroalgal resources in the UK 21313.2 Suitability of macroalgae for biofuel production 21413.3 Biofuels from Macroalgae 21713.3.1 Introduction 21713.3.2 Ethanol from laminarin, mannitol and alginate 21713.3.3 Ethanol from cellulose 21913.3.4 Butanol 22013.3.5 Anaerobic digestion 22113.3.6 Thermochemical conversions 22313.4 Future prospects 22313.5 Conclusion 224Acknowledgements 224Selected References and Suggestions for Further Reading 22414 Lipid‐based Biofuels from Oleaginous Microbes 227Lisa A. Sargeant, Rhodri W. Jenkins and Christopher J. ChuckSummary 22714.1 Introduction 22714.2 Microalgae 22914.3 Oleaginous Yeasts 23114.4 Feedstocks for Heterotrophic Microbial Cultivation 23114.5 The Biochemical Process of Lipid Accumulation in Oleaginous Yeast 23214.6 Lipid Profile of Oleaginous Microbes 23614.7 Lipid Extraction and Processing 23714.8 Concluding Comments 237Selected References and Suggestions for Further Reading 23915 Engineering Microbial Metabolism for Biofuel Production 241Thomas P. HowardSummary 24115.1 Introduction 24115.2 Designer Biofuels 24215.2.1 Introduction 24215.2.2 Isoprenoid‐Derived Biofuels 24315.2.3 Higher Alcohols 24515.2.4 Fatty Acid‐Derived Biofuels 24715.2.5 Petroleum Replica Hydrocarbons 24915.3 Towards Industrialisation 25115.3.1 Introduction 25115.3.2 Bioconsolidation 25115.3.3 Molecular and Cellular Redesign 25515.3.4 Biofuel Pumps 25615.3.5 Synthetic Biology and Systems Engineering 25715.4 Conclusion 258Selected References and Suggestions for Further Reading 25916 The Sustainability of Biofuels 261J.M. LynchSummary 26116.1 Introduction 26116.2 Bioenergy policies 26216.3 Economics of bioenergy markets 26316.4 Environmental issues 26416.5 Life Cycle Assessment 26616.5.1 General features 26616.5.2 OECD Copenhagen workshop, 2008 26716.6 Conclusions 270Selected references and suggestions for further reading 27117 Biofuels and Bioenergy – Ethical Aspects 273John A. Bryant and Steve HughesSummary 27317.1 Introduction to ethics 27317.1.1 How do we Make Ethical or Moral Decisions? 27317.1.2 Environmental ethics 27517.2 Biofuels and Bioenergy – Ethical Background 27617.3 The Key Ethical Issues 27617.3.1 Biofuel production and the growth of Food Crops 27617.3.2 Is growth of Biofuel Crops Sustainable? 27817.3.3 Biofuel Production, Land Allocation and Human Rights 27917.4 Concluding comment 283Selected references and suggestions for further reading 28318 Postscript 285John Love and John A. BryantSelected References and Suggestions for Further Reading 287Index 289