Routes to Cellulosic Ethanol (eBook)

Marcos S. Buckeridge, is a biologist who worked for more than 20 years with the structure and function of plant cell walls. After many years at the Botanical Garden of São Paulo, he moved to the University of São Paulo where incorporated in his lines of research investigation of sugarcane cell walls and sugarcane physiology. At the same time he founded the Laboratory or Plant Physiological Ecology (LAFIECO) dedicated exclusively to study the effects of the global climate changes on crop and native rain forest species. He will be one of the lead authors of the IPCC report for 2014. Buckeridge helped to found the BioEn-FAPESP, one or the most important research programs in bioenergy in Brazil. More recently he became coordinator of the National Institute of Science and Technology of Bioethanol, and is now the scientific director of the Brazilian Bioethanol Science and Technology National Laboratory (CTBE) at Campinas, Brazil. He is communicating editor for the journals Trees: structure and function, Global Change Biology Bioenergy and Bioenergy Research. Gustavo H. Goldman is a biologist, Professor of Molecular Biology at the Universidade de Sao Paulo, Brazil, Researcher of the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brazil, and a former fellow of the John Simon Guggenheim Foundation, USA. He is also an Associate Researcher at the Brazilian Bioethanol Science and Technology National Laboratory (CTBE) at Campinas, Brazil, and Visiting Professor at the Universidade do Minho, Portugal. His expertise is on the molecular genetics of fungi mainly working on the molecular biology of Aspergilli. Goldman has been working with fungal genomics for many years and has several collaborations with the JCVI and the Brod Institute-MIT, both at USA. He is currently Associate Editor of PLoS One, Fungal Genetics and Biology, and BMC Genomics.

Introduction 6
Contents 8
Contributors 10
Part I:Bioenergy 14
Chapter 1: The Role of Biomass in the World’s Energy System 15
1 Introduction 15
2 Energy and Transportation 17
3 Environmental Impacts 17
4 Strategies to Face the Impacts of Transportation 20
5 Biodiesel and Ethanol 21
6 Second Generation Technologies 24
References 26
Chapter 2: Bioenergy and the Sustainable Revolution 27
1 Introduction 27
2 Energy Revolution 28
2.1 Mitochondrial Revolution 28
2.2 Modern Bioenergy: A Sustainable Revolution 29
3 Choices for Renewable Fuels 30
3.1 Biodiesel from Plant Sources 31
3.2 Bioethanol 32
3.3 Biochemical Conversion 33
3.4 Thermochemical Conversion 34
3.5 Comparison of Thermochemical and Biochemical Routes 36
4 Concluding Remarks 36
References 38
Chapter 3: Biomass Gasification for Ethanol Production 39
1 Introduction 39
2 Gasification of Biomass for Biofuels Production 40
3 Synthesizing Biofuels from Syngas 45
3.2 Chemical Synthesis 46
3.3 Biochemical Synthesis 48
4 Current Development of Ethanol Production by Biomass Gasification 49
5 Final Comments 51
References 52
Part II:Plant Cell Walls, Enzymes,and Metabolism 54
Chapter 4: Hemicelluloses as Recalcitrant Components for Saccharification in Wood 55
1 Introduction 55
2 Crystal Regions and the Presence of Lignin 56
3 Xylan 58
4 Xyloglucan 59
5 Glucomannan 60
6 Conclusion 60
References 61
Chapter 5: Topochemistry, Porosity and Chemical Composition Affecting Enzymatic Hydrolysis of Lignocellulosic Materials 63
1 Introduction 63
2 Cell Wall in Lignified Plants: Structure, Chemical Composition, and Recalcitrance to Natural Decay 64
3 Topochemistry, Porosity, and Chemical Composition Determining Successful Enzymatic Hydrolysis of Lignocellulosic Materials 67
4 Lignocellulose Pretreatment by Dilute Acid Hydrolysis and Analogous Technologies 70
5 Lignin-Depleted Plants for Improved Enzymatic Hydrolysis 71
6 Enzymatic Hydrolysis of Lignocellulosic Materials 72
7 Final Remarks 76
References 78
Chapter 6: Enzymology of Plant Cell Wall Breakdown: An Update 83
1 Introduction 83
2 Cellulases 84
2.1 Cellobiose Dehydrogenase 86
3 Hemicellulases 86
3.1 Xylanases 87
3.2 Arabinofuranosidases 87
3.3 Feruloyl esterase 88
3.4 Coumaroyl Esterase 90
3.5 Xyloglucanases 91
3.6 Mannanases 91
4 Glucuronidases 92
5 Pectinases 93
5.1 Protopectinases 93
5.2 Polygalacturonase 93
5.3 Lyases 94
6 Swollenin 94
7 GH 61 95
8 Laccase 96
9 Industrial Application of Enzymes 97
10 Conclusions 100
References 101
Chapter 7: Enzymes in Bioenergy 107
1 Introduction 107
2 Cellulose 108
3 Hemicellulose 115
4 Lignin 117
References 119
Chapter 8: Hydrolases from Microorganisms used for Degradation of Plant Cell Wall and Bioenergy 124
1 Introduction 124
2 Biomass and Biofuels 125
3 Sugarcane and Bioemass 126
4 Sugarcane Bagasse and Energy Production 127
5 Component of Sugarcane Bagasse 127
6 Cell Wall Degrading Enzymes 131
7 Microbial Cellulose Degradation 132
8 Microbial Hemicellulose Degradation 133
9 Microbial Lignin Enzymes 137
10 Microbial Enzymes and Thermophile 137
11 Perspectives 138
References 139
Chapter 9: Cellulase Engineering for Biomass Saccharification 144
1 Introduction 144
2 Cellulose and Cellulases 144
3 Protein Engineering Strategies 146
3.1 Cellulase Engineering by Rational Design 146
3.2 Random Mutagenesis – Directed Evolution 147
3.3 In Vitro Recombination – DNA Shuffling 148
3.4 Screening Randomized DNA Libraries 149
4 Engineering of Cellulase Properties 149
4.1 Cellulases Contain Substrate Binding and Catalytic Domains 149
4.2 The Cellulose-Binding Domain – An Example of a Carbohydrate-Binding Module 150
4.3 Binding Models – What Type of Intermolecular Interaction is Important? 151
4.4 Cellulose (Substrate) Binding to the Catalytic Domain 152
4.5 Engineering the Catalytic Mechanism of Cellulases 153
5 Enzyme Chimeras 154
5.1 CBM/Catalytic Domain Fusions 154
5.2 Multifunctional Enzymes 155
6 Perspectives 156
References 156
Chapter 10: Genetic Improvement of Xylose Utilization by Saccharomyces cerevisiae 161
1 Introduction 161
2 Ethanol Production by Xylose-Fermenting Yeasts 162
3 Factors Limiting Xylose Metabolism in S. cerevisiae 163
3.1 Xylose Uptake 164
3.2 Xylose Isomerase (XI) 165
3.3 Redox Imbalance from Xylose Reductase and Xylitol Dehydrogenase and Xylulokinase 165
3.4 The Nonoxidative PPP Enzymes: Transaldolase and Transketolase 167
4 Adaptation of S. cerevisiae Strains for Efficient Xylose Metabolism 167
5 Concluding Remarks 168
References 168
Part III:Plant Cell Wall Genetics 172
Chapter 11: Tropical Maize: Exploiting Maize Genetic Diversity to Develop a Novel Annual Cropfor Lignocellulosic Biomass and SugarProduction 173
1 Introduction 173
2 Advantages of Tropical Maize as Comparedwith Other Biofuel Crops 175
3 Tropical Maize as a Flexible Biofuel Feedstock 178
4 Biological Properties Driving Superior Sugar Productionand Biomass in Tropical Maize 179
4.1 Tropical Maize as a Sugar Crop 179
4.2 Tropical Maize as a Lignocellulosic Crop 180
4.2.1 Chemical Structure of Lignocellulosic Biomass 181
4.2.2 Genetic Improvement of Lignocellulosic Biomass in Tropical Maize 182
5 Conclusion 183
References 184
Chapter 12: Improving Efficiency of Cellulosic Fermentation via Genetic Engineering to Create “Smart Plants” for Biofuel Production 186
1 Introduction 186
1.1 Biofuels as Green Alternatives to Fossil Fuels: Considerations and Current Status 186
1.2 General Strategies for Improving Biomass Deconstruction Efficiency Through Feedstock Alteration 189
2 Genetic Engineering Approaches to Improve Biomass Fermentability 190
2.1 Overexpressing Cell Wall-Degrading Enzymes in Plants: Tapping the Plant’s Own Machinery for Deconstruction 190
2.2 Tools for Engineering Cell Wall-Degrading Enzymes in Feedstocks 191
2.3 Approaches to Enhance Protein Expression of CellWall-Degrading Enzymes in Transgenic Plants 192
2.4 Contrasting Nuclear and Plastid Transformation Strategies:The Mix-Stock Approach 195
2.5 Modifying the Lignin Content in Lignocellulose Through Genetic Engineering 197
3 Future Perspective 199
References 199
Chapter 13: Sugarcane Breeding and Selection for more Efficient Biomass Conversion in Cellulosic Ethanol 203
1 Introduction 203
2 Characterization and Use of Biodiversity in Sugarcane Breeding 204
2.1 Interspecific Cross 205
2.2 Intergeneric Crosses 206
3 Breeding of Sugarcane in Brazil 207
4 Sugarcane Breeding: Flowering and Crossing 209
5 Common Crossing Strategies 210
6 Biparental Cross 211
7 Multiparental Cross 211
8 Recurrent Selection and Crossing Planning 212
9 Heritance of Principal Characters 214
10 Stages for the Development of a New Sugarcane Cultivar 216
11 Selection in Original Seedlings on FT-1 218
12 FT2 218
13 FT3 219
14 FT4 219
15 FT5 and FT6 219
16 FT7 219
17 FT8 220
18 Active Clone Exchange Between Breeder Teams 220
19 Cultivar Launching Phase 220
20 Breeding for Physiological Traits that Affect Biomass Production 221
21 Limitations of Cellulosic Ethanol Production from Sugarcane Bagasse 223
22 Breeding Sugarcane for Better Efficiency of Cellulosic Ethanol Production 224
24 Development of High-throughput Methods for Characterization of Cell Wall Traits Important for Cellulosic Ethanol Production 229
25 Tools Needed to Speed up Sugarcane Breeding 232
26 Coproducts from Cellulosic Ethanol Production 233
27 Transgenic Plants and Mutants and its Potential to Contribute to Better Effiency of Cellulosic Ethanol Production 233
28 Emerging New Market for Energy and Sugarcane Bagasse Use 234
29 Conclusions 236
References 237
Chapter 14: Cell Wall Genomics in the Recombinogenic Moss Physcomitrella patens 244
1 Introduction 244
2 Identifying Genes and Gene Function 246
2.1 Approaches for Forward and Reverse Genetics 247
3 Functional Genomics in Physcomitrella patens 249
4 Physcomitrella Growth and Development 251
5 Features of the Physcomitrella Plant Cell Wall 252
6 Target Identification and Functional Assay 258
7 Prospects and Outlook 261
References 262
Index 265