Genetic Improvement of Bioenergy Crops

Ethanol as an alternative fuel is receiving a lot of attention because it addresses concerns related to dwindling oil supplies, energy independence, and climate change. The majority of the ethanol in the US is produced from corn starch. With the US Department of Energy's target that 30% of the fuel in the US is produced from renewable resources by 2030, the anticipated demand for corn starch will quickly exceed the current production of corn. This, plus the concern that less grain will become available for food and feed purposes, necessitates the use of other feedstocks for the production of ethanol. For the very same reasons, there is increasing research activity and growing interest in many other biomass crops.

Genetic Improvement of Bio-Energy Crops focuses on the production of ethanol from lignocellulosic biomass, which includes corn stover, biomass from dedicated annual and perennial energy crops, and trees as well as a number of important biomass crops. The biomass is typically pretreated through thermochemical processing to make it more amenable to hydrolysis with cellulolytic enzymes. The enzymatic hydrolysis yields monomeric sugars that can be fermented to ethanol by micro-organisms. While much emphasis has been placed on the optimization of thermo-chemical pretreatment processes, production of more efficient hydrolytic enzymes, and the development of robust microbial strains, relatively little effort has been dedicated to the improvement of the biomass itself.

Genetic Improvement of Bioenergy Crops

Wilfred Vermerris, Editor

Bioenergy is attracting increasing attention in science, industry, politics and the media as a means to address energy security, global climate change and economic sustainability. Biofuels - ethanol and biodiesel - currently represent the only alternative and renewable energy source available as liquid transportation fuel. The current production of biofuels relies heavily on food crops: grain and sugar for ethanol, and plant oils for biodiesel. This has raised serious concerns about food supplies, food prices, and long-term sustainability. Second-generation biofuels are derived from dedicated bioenergy crops that produce plant cell wall polysaccharides as the main source of fermentable sugars, as well as algae and non-edible oil crops as a source of oils and lipids for biodiesel.

The development of dedicated bioenergy crops requires an entirely different approach to plant improvement than what has been traditional for food, feed and fiber crops. This book presents an overview of the major bioenergy crops that can be used for the production of biomass and ethanol, with a focus on their genetic improvement. In order to maintain focus, biodiesel and the genetic improvement of oil crops are not covered. The available genetic resources are largely untapped and offer major opportunities to significantly enhance the contribution of bioenergy, while addressing many of the economic and ecological concerns.

The chapters have been written by experts in their field and target university students in plant sciences, biological engineering, or related disciplines, enrolled in a course on bioenergy crops. Researchers in academia and industry will find this book useful as well. The first part of the book provides background on the politics of bioenergy, the current ethanol production process, the biosynthesis and analysis of plant cell walls, andprocessing of biomass, and includes a primer on genetics and plant breeding. The second part of the book focuses on the genetic resources available to enhance individual herbaceous and woody species for use as bioenergy feedstocks. As a whole, Genetic Improvement of Bioenergy Crops provides the first comprehensive overview of the tremendous potential of dedicated bioenergy crops.

Wilfred Vermerris is Associate Professor at the Genetics Institute and Agronomy department at the University of Florida in Gainesville, where he manages an active research program on plant cell walls and their use in bioenergy applications. He is also faculty associate with the University of Florida's Plant Molecular and Cellular Biology graduate program, Adjunct Associate Professor in Agricultural & Biological Engineering at Purdue University and adjunct faculty member of Purdue University's Laboratory of Renewable Resources Engineering. He is co-author of the book Phenolic Compound Biochemistry (Springer 2006) and one of the three Co-Editors-in-Chief of the journal BioEnergy Research.