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List of Contributors xiii Preface xv List of Abbreviations xix 1 Biofuels: The Back Story 1 John A. Bryant and John Love Summary 1
1.1 Introduction 1
1.2 Some history 1
1.2.1 Wood and charcoal 1
1.2.2 Dung as fuel 2
1.2.3 Oils and fats 2
1.2.4 Peat 3
1.3 Fossil fuels 4
1.3.1 Coal 4
1.3.2 Petroleum Oil 5
1.3.3 Natural gas 6
1.4 Fossil fuels and Carbon Dioxide 6
1.4.1 The Club of Rome 6
1.4.2 Climate change 7
1.5 Alternative Energy Sources 9
1.5.1 Introduction 9
1.5.2 Environmental Energy Sources 9
1.5.3 Nuclear power 15
1.5.4 Hydrogen 17
1.6 Biofuels 18 Selected references and suggestions for further reading 19 2 Biofuels in Operation 21 Lionel Clarke Summary 21
2.1 Fuels for Transport 21
2.2 Future Trends in Fuels Requirements and Technology 24
2.3 Engines and Fuels - Progress vs Inertia 26
2.4 Engine Constraints, Fuel Specifications and Enhanced Performance 28
2.5 Biofuels - Implications and Opportunities 32
2.5.1 Introduction 32
2.5.2 Ethanol 32
2.5.3 Biodiesel 33
2.6 Advanced Biofuels as Alternatives to Ethanol and FAME 37
2.7 Biofuels for Aviation; ''Biojet'' 40
2.8 Impact of Future Trends in Engine Design on Retail Biofuels 42
2.9 Conclusion 43 Selected References and Suggestions for Further Reading 43 3 Anaerobic Digestion 45 John Bombardiere and David A. Stafford Summary 45
3.1 History and Development of Anaerobic Digestion 45
3.1.1 Introduction 45
3.1.2 Mixtures of MicroOrganisms 46
3.2 Anaerobic Digestion: The Process 47
3.2.1 General Biochemistry 47
3.2.2 Design Types 47
3.2.3 Complete Mix Design 47
3.2.4 Plug Flow Digesters 48
3.2.5 High Dry Solids AD Systems 49
3.2.6 Upflow Anaerobic Sludge Blanket (UASB) 50
3.2.7 Anaerobic Filters 50
3.3 Commercial applications and benefits 51
3.3.1 In the United Kingdom 51
3.3.2 In the USA 51
3.3.3 In Germany 52
3.3.4 Overall Benefits 52
3.4 Ethanol Production Linked with Anaerobic Digestion 53
3.5 Financial and Economic Aspects 54
3.6 UK and US Government Policies and Anaerobic Digestion - an overview 55
3.7 Concluding Comments 56 Selected References and Suggestions for Further Reading 57 4 Plant Cell Wall Polymers 59 Stephen C. Fry Summary 59
4.1 Nature and Biological Roles of Primary and Secondary Cell Walls 59
4.2 Polysaccharide Composition of Primary and Secondary Cell Walls 60
4.2.1 Typical dicots 60
4.2.2 Differences in Certain Dicots 67
4.2.3 Differences in Monocots 67
4.2.4 Differences in Gymnosperms 68
4.2.5 Differences in Nonseed Landplants 68
4.2.6 Differences in Charophytes 68
4.3 Postsynthetic Modification of Cellwall Polysaccharides 70
4.3.1 C rosslinking of cellwall polysaccharides 70
4.3.2 Hydrolysis of Cellwall Polysaccharides 72
4.3.3 ''Cutting and Pasting'' (Transglycosylation) of Cellwall Polysaccharide Chains 75
4.4 Polysaccharide Biosynthesis 77
4.4.1 General Features 77
4.4.2 At the Plasma Membrane 77
4.4.3 In the Golgi System 78
4.4.4 Delivering the Precursors - sugar Nucleotides 79
4.5 Nonpolysaccharide Components of the Plant Cell Wall 80
4.5.1 Extensins and Other (Glyco)Proteins 80
4.5.2 Polyesters 83
4.5.3 Lignin 84
4.5.4 Silica 84
4.6 Conclusions 85 Acknowledgements 85 Appendix 85 Selected References and Suggestions for Further Reading 85 5 Ethanol Production from Renewable Lignocellulosic Biomass 89 Leah M. Brown, Gary M. Hawkins and Joy Doran-Peterson Summary 89
5.1 Brief History of FuelEthanol Production 89
5.2 Ethanol Production from Sugar Cane and Corn 92
5.3 Lignocellulosic Biomass as Feedstocks for Ethanol Production 93
5.3.1 The Organisms 93
5.3.2 Lignocellulosic Biomass 96
5.3.3 Pretreatment of Lignocellulosic Biomass 99
5.3.4 Effect of Inhibitory Compounds on Fermenting Microorganisms 100
5.4 Summary 102
5.5 Examples of Commercial Scale Cellulosic Ethanol Plants 103
5.5.1 Beta Renewables/Biochemtex Commercial Cellulosic Ethanol Plants in Italy, Brazil, USA and Slovak Republic 103
5.5.2 PoetDSM ''Project Liberty'' - First Commercial Cellulosic Ethanol Plant in the USA 103
5.5.3 Abengoa Hugoton, Kansas commercial plant and MSW to ethanol Demonstration Plant, Salamanca 103 Selected References, Suggestions for Further Reading and Useful Websites 104 6 Fatty Acids, Triacylglycerols and Biodiesel 105 John A. Bryant Summary 105
6.1 Introduction 105
6.2 Synthesis of Triacylglycerol 107
6.2.1 The Metabolic Pathway 107
6.2.2 Potential for Manipulation 110
6.3 Productivity 111
6.4 Sustainability 114
6.5 More Recently Exploited and Novel Sources of Lipids for Biofuels 114
6.5.1 Higher Plants 114
6.5.2 Algae 115
6.5.3 Prokaryotic Organisms 116
6.6 Concluding Remarks 117 Selected References and Suggestions for Further Reading 117 7 Development of Miscanthus as a Bioenergy Crop 119 John Clifton Brown, Jon McCalmont and Astley Hastings Summary 119
7.1 Introduction 119
7.2 Developing Commercial Interest 122
7.3 Greenhouse Gas Mitigation Potential 127
7.4 Perspectives for ''now'' and for the Future 128 Selected References and Suggestions for Further Reading 129 8 Mangrove Palm, Nypa fruticans: ''3 in 1'' Tree for Integrated Food/Fuel and Eco Services 133 C.B. Jamieson, R.D. Lasco and E.T. Rasco Summary 133
8.1 Introduction: the ''Food vs Fuel'' and ''ILUC'' Debates 133
8.2 Integrated FoodEnergy Systems (IFES): a Potential Solution 134
8.2.1 Main Features of IFES 134
8.2.2 Baseline Productivity 136
8.3 Land use: the Importance of Forest Ecosystem Services 137
8.4 Sugar Palms: Highly Productive MultiPurpose Trees 138
8.5 Nipa (Nipa fruticans): a Mangrove Sugar Palm with Great Promise 140
8.6 Conclusion 141 Selected References and Suggestions for Further Reading 141 9 The Use of Cyanobacteria for Biofuel Production 143 David J. Lea Smith and Christopher J. Howe Summary 143
9.1 Essential Aspects of Cyanobacterial Biology 143
9.1.1 General Features 143
9.1.2 Photosynthesis and Carbon Dioxide Fixation 144
9.1.3 Nitrogen Fixation 146
9.2 Commercial Products Currently Derived from Cyanobacteria 146
9.3 Cyanobacteria Culture 147
9.4 Cyanobacterial Genomes and Genetic Modification for Biofuel Production 148
9.5 Industrial Production of Biofuels from Cyanobacteria 152
9.6 Conclusion 154 Selected References and Suggestions for Further Reading 154 10 Third Generation Biofuels from the Microalga, Botryococcus braunii 157 Charlotte Cook, Chappandra Dayananda, Richard K. Tennant and John Love Summary 157
10.1 Botryococcus braunii 157
10.2 Microbial Interactions 160
10.3 Botryococcus braunii as a Production Platform for Biofuels or Chemicals 161
10.3.1 Hydrocarbons, Lipids and Sugars 161
10.3.2 Controlling and Enhancing Productivity 163
10.3.3 Alternative Culture Systems 165
10.3.4 Harvesting Botryococcus Biomass and Hydrocarbons 166
10.3.5 Processing Botryococcus into an Alternative Fuel 166
10.4 Improving Botryococcus 167
10.5 Future Prospects and Conclusion 169 Selected References and Suggestions of Further Reading 170 11 Strain Selection Strategies for Improvement of Algal Biofuel Feedstocks 173 Leyla T. Hathwaik and John C. Cushman Summary 173
11.1 Introduction 173
11.2 Lipids in Microalgae 174
11.3 Starch in Microalgae 175
11.4 Metabolic Interconnection Between Lipid and Starch Biosynthesis 176
11.5 Strategies for the Selection of Microalgae Strains with Enhanced Biofuel Feedstock Traits 177
11.5.1 Manipulation of Growth Conditions 177
11.5.2 Genetic Mutagenesis 177
11.5.3 F low Cytometry 178
11.5.4 FluorescenceActivated Cell Sorting 181
11.5.5 Buoyant Density Centrifugation 183
11.6 Conclusions 185 Acknowledgements 185 Selected References and Suggestions for Further Reading 185 12 Algal Cultivation Technologies 191 Alessandro Marco Lizzul and Michael J. Allen Summary 191
12.1 Introduction 191
12.2 Lighting 192
12.3 Mixing 194
12.4 Control Systems and Construction Materials 196
12.5 Algal Production Systems at Laboratory Scale 197
12.6 Algal Production in Open Systems 198
12.6.1 PondBased Systems 198
12.6.2 Membrane Reactors 200
12.7 Algal production in Closed Systems 201
12.7.1 Introduction 201
12.7.2 Plate or Panel Based Systems 201
12.7.3 Horizontal Tubular Systems 203
12.7.4 Bubble Columns 205
12.7.5 Airlift Reactors 207
12.8 Concluding Comments 209 Selected References and Suggestions for Further Reading 209 13 Biofuels from