Dr Jianzhong Sun is a distinguished professor of entomology and bioenergy and is Director of the Biofuels Institute at Jiangsu University in China. He is also Adjunct Professor in the Department of Biological Systems Engineering at Washington State University in the USA. Dr Sun's research focuses mainly on the utilization of wood-feeding termites/other cellulolytic insects to develop the novel technologies for lignocellulosic biofuels and other bio-products. He initiated and chaired the first symposium on Lignocellulose Degradation by Insects and their Gut Symbionts with Potential Applications to the Biofuels Industry held at the 2008 annual conference of the Entomological Society of America in the USA. Dr Sun also edited a special issue entitled Insects and Biofuels for the Insect Science Journal in June 2010. To date, Dr Sun has published over 60 scientific papers, 4 book chapters, and a journal special issue on a variety of topics including biomass utilization, entomology, microbiology and biofuels. Dr Shi-You Ding is a plant biologist and biochemist specializing in the ultrastructure of plant cell walls and cell-wall-degrading enzymes. He has pioneered nanometer-scale studies of plant cell wall structures and the changes occurring in them during biomass conversion processes. Dr Ding currently leads several projects funded by the US Department of Energy. These are aimed at developing a deeper understanding of plant cell wall structure and processing of plant cell wall material to biofuels and bio-products. Dr Ding also has extensive experience in the biochemistry of cellulase systems including cellulosomes and fungal cellulases, as well as natural cellulolytic microbial communities. Based on the insights gained from micro- and nanoscale structure studies, he and his colleagues use molecular engineering approaches to build new chimeric enzyme proteins and to formulate mixtures of cellulases that work more efficiently to deconstruct cell-wall material and harvest its component chemicals for conversion to biofuels. Dr Ding has authored or co-authored more than 60 peer-reviewed papers and holds six US patents on thermophilic cellulases that have been licensed to industry. Dr Joy Doran-Peterson is Associate Professor of Microbiology at the University of Georgia in the USA. She is a microbiologist and bioengineering scientist. Her main research activities focus on biofuels, metabolic pathway engineering, fermentation, characterization of environmental microorganisms, and microbial ecology. Dr Peterson has published more than 30 professional papers, including book chapters, on cellulosic biofuels and the discovery of novel microbes for SSF and CBP strategies. Dr. Peterson has also pioneered cutting-edge technologies to isolate novel bacterial symbionts from cellulose-feeding insects and their application in industrial biorefinery systems for the production of lignocellulosic ethanol.

Dr Jianzhong Sun is a distinguished professor of entomology and bioenergy and is Director of the Biofuels Institute at Jiangsu University in China. He is also Adjunct Professor in the Department of Biological Systems Engineering at Washington State University in the USA. Dr Sun's research focuses mainly on the utilization of wood-feeding termites/other cellulolytic insects to develop the novel technologies for lignocellulosic biofuels and other bio-products. He initiated and chaired the first symposium on Lignocellulose Degradation by Insects and their Gut Symbionts with Potential Applications to the Biofuels Industry held at the 2008 annual conference of the Entomological Society of America in the USA. Dr Sun also edited a special issue entitled Insects and Biofuels for the Insect Science Journal in June 2010. To date, Dr Sun has published over 60 scientific papers, 4 book chapters, and a journal special issue on a variety of topics including biomass utilization, entomology, microbiology and biofuels. Dr Shi-You Ding is a plant biologist and biochemist specializing in the ultrastructure of plant cell walls and cell-wall-degrading enzymes. He has pioneered nanometer-scale studies of plant cell wall structures and the changes occurring in them during biomass conversion processes. Dr Ding currently leads several projects funded by the US Department of Energy. These are aimed at developing a deeper understanding of plant cell wall structure and processing of plant cell wall material to biofuels and bio-products. Dr Ding also has extensive experience in the biochemistry of cellulase systems including cellulosomes and fungal cellulases, as well as natural cellulolytic microbial communities. Based on the insights gained from micro- and nanoscale structure studies, he and his colleagues use molecular engineering approaches to build new chimeric enzyme proteins and to formulate mixtures of cellulases that work more efficiently to deconstruct cell-wall material and harvest its component chemicals for conversion to biofuels. Dr Ding has authored or co-authored more than 60 peer-reviewed papers and holds six US patents on thermophilic cellulases that have been licensed to industry. Dr Joy Doran-Peterson is Associate Professor of Microbiology at the University of Georgia in the USA. She is a microbiologist and bioengineering scientist. Her main research activities focus on biofuels, metabolic pathway engineering, fermentation, characterization of environmental microorganisms, and microbial ecology. Dr Peterson has published more than 30 professional papers, including book chapters, on cellulosic biofuels and the discovery of novel microbes for SSF and CBP strategies. Dr. Peterson has also pioneered cutting-edge technologies to isolate novel bacterial symbionts from cellulose-feeding insects and their application in industrial biorefinery systems for the production of lignocellulosic ethanol.

Biological Conversion of Biomass for Fuels and Chemicals

Exploration from Natural Utilization Systems

By Jianzhong Sun, Shi-You Ding, Joy Doran-Peterson

The Royal Society of Chemistry

Copyright © 2014 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-1-84973-424-0

Contents

Chapter 1 Biomass and its Biorefinery: Novel Approaches from Nature-Inspired Strategies and Technology Jianzhong Sun, Shi-You Ding and Joy Doran-Peterson, 1,
Chapter 2 Overview of Lignocellulose: Structure and Chemistry Shi-You Ding, 14,
Chapter 3 Advances in the Measurement and Characterization of Biomass Structure and Processing Yu-San Liu and Shi-You Ding, 26,
Chapter 4 Lignin Modification to Reduce the Recalcitrance of Biomass Processing Bassem B. Hallac and Arthur J. Ragauskas, 37,
Chapter 5 Advances in the Genetic Manipulation of Cellulosic Bioenergy Crops for Bioethanol Production Chuansheng Mei and Callista Rakhmatov, 53,
Chapter 6 The Diversity of Lignocellulosic Biomass Resources and their Evaluation for Use as Biofuels and Chemicals Peng Chen and Liangcai Peng, 83,
Chapter 7 Technologies to Study Plant Biomass Fermentation Using the Model Bacterium Clostridium Phytofermentans Andrew C. Tolonen, Elsa Petit, Jeffrey L. Blanchard, Tom Warnick and Susan B. Leschine, 114,
Chapter 8 Lignocellulose Degradation in Termite Symbiotic Systems Lei Xie, Ning Liu and Yongping Huang, 140,
Chapter 9 Functional Gene Resources from Cellulose-Feeding Insects for Novel Catalysts Hirofumi Watanabe and Jinfeng Ni, 156,
Chapter 10 Biological Pretreatment of Biomass in Wood-Feeding Termites Jing Ke and Shulin Chen, 177,
Chapter 11 Lignocellulolytic Systems of Insects and their Potential for Viable Biofuels Jianzhong Sun and Xuguo Joe Zhou, 195,
Chapter 12 The Lignocellulolytic Wood-Feeding Cockroach — A Forgotten Treasure Xiangrui Li and Xuguo Zhou, 223,
Chapter 13 Reverse Design of Natural Biomass Utilization Systems for Biomass Conversion Ryan D. Syrenne, Shangxian Xie, Jianzhong Sun and Joshua S. Yuan, 237,
Chapter 14 The Ruminant Animal as a Natural Biomass-Conversion Platform and a Source of Bioconversion Agents Paul J. Weimer, 248,
Chapter 15 Tipula abdominalis: a Natural Biorefinery with Novel Microbial Enzymes Useful for Pectin-Rich Biomass Deconstruction Dana M. Schneider, Emily D. Henriksen, Whitney E. Boland, Meredith C. Edwards and Joy Doran-Peterson, 282,
Chapter 16 Cloning, Mutation and Over-Expression of Lignocellulase Genes Weilan Shao, 298,
Chapter 17 Cellulose-Dissolving Systems and their Effects on Enzymatic Hydrolysis Kun Wang, Feng Xu and Run-Cang Sun, 318,
Chapter 18 What We Can Learn From Natural Biomass-Utilization Systems for Developing Novel Bioreactors Yinhua Wan, Benkun Qi, Jianmin Xing, Qiang Liao, Jianzhong Sun and Shulin Chen, 344,
Chapter 19 Techno-Economic Analysis and Life-Cycle Assessment of Lignocellulosic Biomass to Sugars Using Various Pretreatment Technologies Ling Tao, Eric C. D. Tan, Andy Aden and Richard T. Elander, 358,
Subject Index, 381,

CHAPTER 1

Biomass and its Biorefinery: Novel Approaches from Nature-Inspired Strategies and Technology

JIANZHONG SUN, SHI-YOU DING AND JOY DORAN-PETERSON

1.1 Current Technologies in the Biological Conversion of Biomass to Biofuels

Biofuels have been around since modern cars were invented. Early engines were designed to be able to run on ethanol or vegetable oil. However, the discovery of huge deposits of petroleum led to the development of refinery-based fossil fuels, and have provided a cheap supply of gasoline and diesel for decades. Although the concept of biofuels has never been forgotten, industrial-scale biofuel production has yet to be developed. Recently, increased gasoline prices, environmental concerns, and the security of energy supplies have drawn much public attention. Many countries have therefore promoted the research and development (R&D) of alternative fuels in response to these concerns. One of the promising routes towards alternative energy is biofuels produced from lignocellulosic biomass through biological conversion processes, in which nonfood resources, such as agricultural and forestry waste, and energy crops, are utilized as feedstock. Processes that include thermochemical pretreatment, enzymatic saccharification, and microbial fermentation are used to convert polysaccharides in biomass into alcohol fuels, such as ethanol for transportation. Although carbohydrates are an energy source for many organisms in nature, the natural decay process by microorganisms is slow, albeit efficient. In order to establish biorefinery and achieve economically competitive biofuel production from biomass, technical challenges and barriers must be overcome to accelerate the development of the growing biofuel industry. The key components involved are sustainable feedstock supply, optimized bioconversion technologies, and integrated biorefinery on an industrial scale.

The R&D of feedstock supply and logistics has been focused on developing techniques to provide sustainable biomass supply (quantity) and quality in production, harvest, storage, handling, and transportation. Preprocessing treatments, such as reduction of particle size, drying, blending, and densification, have also been tested to standardize the feedstock supply chain, reduce transportation costs, and to upgrade biomass reactivity in down-stream operations.

Current biomass conversion technology normally consists of three steps: thermochemical pretreatment, enzymatic saccharification, and microbial fermentation. Pretreatment is a process that conditions biomass feedstock to be amenable to cellulolytic enzymes to break down structural polysaccharides to fermentable sugars. Physical pretreatment may include mechanical milling to reduce biomass particle size, steam explosion, and hydrothermolysis. Thermochemical pretreatment normally involves a dilute acid (e.g., H2SO4) or base (e.g., NaOH) to promote hydrolysis by removing hemicellulose and/or lignin. Many other solvents have also been explored and shown to disrupt biomass and promote hydrolysis, such as alkaline H2O2, ozone, organosolv, glycerol, dioxane, phenol, ethylene glycol, concentrated mineral acid, ammonia, metal complexes, and others. For any given feedstock, some methods may be more effective than others. Many pretreatment technologies have been developed aiming to achieve a high yield of sugars and limit the degradation products that may inhibit microbial fermentation. Some of these methods, while effective, are not economically feasible. Due to the limited understanding of the complex structure of biomass, pretreatment is still considered to be the most costly step when the overall cost of the process is taken into account. A recent study seemed to shed light on the rational design of the pretreatment process, suggesting a focus on eliminating the lignin while leaving the structural polysaccharides (i.e., hemicellulose as well as cellulose) intact within the plant cell walls. Such pretreatment would leave an open structure that allows easy access by the enzymes and rapid digestion of polysaccharides.

Enzymatic saccharification is a process which uses an enzyme cocktail that contains a mixture of cellulases, hemicellulases, and accessory enzymes to depolymerize polysaccharides into simple sugars. Currently, commercial enzyme mixtures are developed based exclusively on the fungal cellulases, i.e.,Trichoderma reesei enzymes. After...