Introduction to BIOFUELS. David M. Mousdale. CRC Press. Taylor & Francis Group Boca Raton London New York

Transcription

1 Introduction to BIOFUELS David M. Mousdale CRC Press Taylor & Francis Group Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Croup, an informa business

2 Contents Preface Acknowledgments The Author Units and Conversion Factors xv xxi xxiii xxv Ethanol as the Leading "First-Generation" Biofuel Introduction Historical Development of Ethanol as a Fuel from Neolithic Times to the Twentieth Century Oil Supply and Oil Price in the Twentieth Century: Necessity and Alternative Fuel Programs Case Study 1: Brazil and Sugarcane Ethanol Case Study 2: Starch-Based Ethanol in the United States Thermodynamic and Environmental Aspects of Ethanol as a Biofuel Net Energy Balance Effects on Emissions of Greenhouse Gases and Other Pollutants Summary 41 References 41 Cellulosic Ethanol as a "Second-Generation" Biofuel Introduction Bioethanol and Cellulosic Ethanol: The Rise of Biomass-Based Biofuels Structural and Industrial Chemistry of Cellulosic Biomass Cellulose, Hemicelluloses, and Lignin Lignocellulose as a Biochemical Resource Pretreatment of Lignocellulosic Materials Physical and Chemical Pretreatment of Lignocellulosic Biomass Acid Hydrolysis of Pretreated Lignocellulosic Biomass Cellulases: Biochemistry, Molecular Biology, and Biotechnology Enzymology of Cellulose Degradation by Cellulases Cellulases in Lignocellulosic Feedstock Processing 65 vii

3 viii Contents Molecular Biology and Biotechnology of Cellulase Production Physiological Regulation of Cellulase Production Regulatory Genes Involved in Cellulase Production New-Generation Cellulases Novel Molecular Features of Cellulases Immobilized Cellulases Hemicellulases: New Horizons in Energy Biotechnology A Multiplicity of Hemicellulases Hemicellulases in the Processing of Lignocellulosic Biomass Molecular Biology of Hemicellulases Multifunctional Hemicellulases? Lignin-Degrading Enzymes as Aids to Saccharification Commercial Choices of Cellulosic Feedstocks for Ethanol Production Biotechnology and Platform Technologies for Cellulosic Ethanol Summary 83 References 83 Chapter 3 Microbiology of Cellulosic Ethanol Production I: Yeasts Introduction Traditional Ethanologenic Yeasts Conventional Yeasts Nonconventional Yeasts Metabolic Engineering of Yeasts for Cellulosic Ethanol Increased Pentose Utilization by Ethanologenic Yeasts by Genetic Manipulation with Yeast Genes for Xylose Metabolism via Xylitol Increased Pentose Utilization by Ethanologenic Yeasts by Genetic Manipulation with Genes for Xylose Isomerization Engineering Arabinose Utilization by Ethanologenic Yeasts Comparison of Industrial and Laboratory Yeast Strains for Ethanol Production Improved Ethanol Production by Naturally Pentose-Utilizing Yeasts Toward the Perfect Yeast Ethanologen? "Omic" Analyses of Yeast Metabolism during Ethanol Production Stress Responses in Yeast Ethanologens 120

4 Contents ix 3.5 Summary 121 References 122 Chapter 4 Microbiology of Cellulosic Ethanol Production II: Bacteria Introduction Assembling Gene Arrays in Bacteria for Ethanol Production Metabolic Routes in Bacteria for Sugar Metabolism and Ethanol Formation Genetic and Metabolic Engineering of Bacteria for Cellulosic Ethanol Production Recombinant Escherichia coli: Lineages and Metabolic Capabilities Engineering Zymomonas mobilis for Xylose and Arabinose Metabolism Development of Klebsiella Strains for Ethanol Production Other Bacterial Species Thermophilic Species and Cellulosome Bioproduction Technologies "Designer" Cells and Synthetic Organisms Summary 151 References 152 Chapter 5 Biochemical Engineering of Cellulosic Ethanol Introduction Case Study: The logen Corporation Process with Wheat Straw Biomass Substrate Pretreatment Strategies Wheat Straw Switchgrass Corn Stover Softwoods Sugarcane Bagasse Other Large-Scale Agricultural and Forestry Biomass Feedstocks Fermentation Media and the Very High Gravity Concept Fermentation Media for Ethanol Production High-Concentration Media Developed for Alcohol Fermentations Fermentor Design and Novel Fermentor Technologies Continuous Fermentations for Ethanol Production Fed-Batch Fermentations 187

5 X Contents Immobilized Yeast and Bacterial Cell Production Designs Contamination Events and Buildup in Fuel Ethanol Plants Simultaneous Saccharification and Fermentation and Consolidated Bioprocessing Downstream Processing and By-Products Ethanol Recovery from Fermented Broths Continuous Ethanol Recovery from Fermentors Solid By-Products from Ethanol Fermentations Summary 202 References 203 Chapter 6 The Economics of Fuel Ethanol Introduction Market Forces and Incentives 'he Impact of Oil Prices on the Future of Biofuels after Production Price, Taxation, and Incentives in the Market Economy Cost Models for Fuel Ethanol Production Early Benchmarking Studies of Corn and Lignocellulosic Ethanol in the United States Corn-Derived Ethanol in Wheat-Straw-Derived Ethanol in Fuel Ethanol from Sugarcane Molasses Farm-Scale Ethanol Production Corn Ethanol in the 1980s: Rising Industrial Ethanol Prices and the Development of the Incentive Culture Western Europe in the Mid-1980s: Assessments of Biofuels Programs Made at a Time of Falling Real Oil Prices Brazilian Sugarcane Ethanol in 1985: After the First Decade of the PROÄLCOOL Program to Substitute for Imported Oil Economics of U.S. Corn and Biomass Ethanol Economics in the Mid-1990s Case Study: The View from Sweden Subsequent Assessments of Lignocellulosic Ethanol in Europe and the United States Complete Process Cost Models Reviews of "Gray" Literature Estimates and Economic Analyses 243

6 Contents 6.4 Pilot Plant and Industrial Extrapolations for Cellulosic Ethanol Near-Future Projections for Cellulosic Ethanol Production Costs Short- to Medium-Term Technical Process Improvements and Their Anticipated Economic Impacts Bioprocess Economics: A Chinese Perspective Governmental and Macroeconomic Factors Mandatory Biofuels Targets Impact of Fuel Economy on Ethanol Demand for Gasoline Blends Biofuels Pricing in the Era of Carbon Taxation Summary 259 References 260 Chapter 7 Advanced Biofuels: The Widening Portfolio of Alternatives to Ethanol Introduction Biobutanol and ABE Bacterial Production of C3-C7 Alcohols and Related Compounds Glycerol The MixAlco Process Biohydrogen The Hydrogen Economy and Fuel Cell Technologies Bioproduction of Gases: Methane and H 2 as Products of Anaerobic Digestion Heterotrophic Microbes Producing H 2 by Hydrogenase Activity Nitrogen-Fixing Microorganisms Development of "Dark" H 2 Production Systems Production of H 2 by Photosynthetic Organisms Microbial Fuel Cells: Eliminating the Middlemen of Energy Carriers Summary 293 References 293 Chemically Produced Biofuels Introduction Biodiesel: Chemistry and Production Processes Vegetable Oils and Chemically Processed Biofuels 301

7 xii Contents Biodiesel Composition and Production Processes Biodiesel Economics Energetics of Biodiesel Production and Effects on Greenhouse Gas Emissions Case Study 1: Hydrogenated Plant Oils and "Green Diesel" Case Study 2: Enzymes for Biodiesel Production Fischer-Tropsch Diesel: Chemical Biomass-Liquid Fuel Transformations The Renascence of an Old Chemistry for Biomass-Based Fuels? Economics and Environmental Impacts of FT Diesel Biodiesel from Microalgae and Microbes Marine and Aquatic Biotechnology Microdiesel Chemical Conversions of Glycerol Produced by Fermentation Chemical Routes for the Production of Monooxygenated C6 Liquid Fuels from Biomass Carbohydrates Biomethanol and Biodimethylether Chemistry and the Emergence of the Hydrogen Economy Summary 333 References 334 Chapter 9 Sustainability of Biofuels Production Introduction Delivering Biomass Feedstocks for Cellulosic Ethanol Production: The Logistics of a New Industry Upstream Factors: Biomass Collection and Delivery Limitations Imposed by Land Availability and Land Use Sustainable Development and Biomass Production Definitions, Semantics, and Analysis Case Study: Sustainability of Brazilian Sugarcane Ethanol Future Horizons for Cane Sugar Ethanol Bioenergy Crops and Genetically Manipulated Plants Engineering Resistance Traits for Biotic and Abiotic Stresses Bioengineering Increased Crop Yield 369

8 Contents xiii Optimizing Traits for Energy Crops Intended forbiofuel Production Genetic Engineering of Dual-Use Food Plants and Dedicated Energy Crops Summary 376 References 377 Chapter 10 Biofuels as Products of Integrated Bioprocesses (Biorefineries) Introduction The Biorefinery Concept Biorefinery Entry Routes Fermentation of Biomass-Derived Substrates Biomass Gasification Biorefinery Pivotal Products Case Study 1: Succinic Acid Case Study 2: Xylitol and Rare Sugars as Fine Chemicals Case Study 3: Glycerol Central Substrates and Biorefinery Flexibility When Will the Biobased Economy Be Possible and When Will It Be Unavoidable? Summary 413 References 413 Index 421 4