Genomic Science Program

DOE BioEnergy Science Center (BESC)

Project Description:
The DOE BioEnergy Science Center (BESC), led by Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, is strongly focused on the fundamental understanding and elimination of biomass recalcitrance—the resistance of cellulosic biomass to enzymatic breakdown into sugars. Recalcitrance is the single-greatest barrier to cost-effective production of biofuels. BESC’s approach to making biomass easier to degrade involves (1) designing plant cell walls for rapid deconstruction and (2) engineering a multitalented microbe tailor-made for converting plants into biofuel in a single step—a strategy known as consolidated bioprocessing.

The BESC team consists of ten institutional partners and seven individual investigators with extensive experience in biomass research at other institutions. The new Joint Institute for Biological Sciences (JIBS) systems biology research facility at ORNL serves as the central hub for coordinating research among all BESC partners.

Through understanding the root causes of biomass recalcitrance, BESC’s researchers aim to reduce projected cellulosic biofuel production costs by ultimately developing new bioenergy crops and microbes that can streamline cellulosic biofuel processing. The knowledge generated by this basic research will lay the foundation for improving the productivity of various bioenergy crops, developing diverse fuel products, and ensuring sustainable cellulosic biofuel production. BESC’s research is organized into three focus areas: (1) Biomass Formation and Modification, (2) Biomass Deconstruction and Conversion, and (3) Characterization and Modeling.

Research Strategy:

1. Biomass Formation and Modification
BESC biomass formation and modification research involves working directly with two potential bioenergy crops—switchgrass and poplar—to develop varieties that are easier to break down into fermentable sugars.

Currently, little is known about how cellulose and hemicelluloses are synthesized; distributed within cell walls; and attached to each other, to lignin, or to cell-wall proteins. Molecular, genetic, genomic, biochemical, chemical, and bioinformatics tools are being used to develop computational models of cell-wall biosynthesis in poplar and switchgrass. These models will help BESC researchers identify target genes and successful strategies for modifying biosynthetic pathways to generate biomass that can be readily deconstructed into sugars for biofuel production. Large numbers of plant samples will be generated and studied. By understanding how polysaccharides and lignin making up the biomass are synthesized and assembled, BESC researchers will develop methods for reducing cell-wall recalcitrance that can be applied to a wide range of woody and herbaceous plants.

2. Biomass Deconstruction and Conversion

Two key hypotheses drive BESC’s biomass deconstruction and conversion research: (1) microorganisms can be engineered to enable consolidated bioprocessing (CBP), a gamechanging, one-step, microbe-mediated strategy for directly converting plant biomass into ethanol; and (2) enzymes and microbial biocatalysts can be engineered to synergize with recalcitrance-reducing plant modifications to achieve better biomass deconstruction.

A model organism for CBP development is Clostridium thermocellum, a bacterium that rapidly degrades pure cellulose and then ferments the resulting sugars into ethanol. This microbe’s strategy for combined biomass deconstruction and conversion employs cellulosomes—multifunctional enzyme complexes that specialize in degrading cellulose. Cellulosomes must be understood for rapid improvement in the deconstruction of more complex plant cell walls. BESC is studying the structures and activities of these multienzyme complexes to design new variants with better cell wall–deconstruction capabilities. In addition to working with C. thermocellum, BESC researchers are investigating samples from hot springs at Yellowstone National Park to identify heat-tolerant enzymes and microbes with superior biomass-degrading functions that can be used to discover additional strategies for new CBP microorganisms.

BESC will explore several fundamental frontiers: (1) mining the natural diversity of biomass-degrading enzymes and microbes, (2) studying how different biomass features affect the activities of enzymes and microbes, (3) examining the relationship between enzyme structure and function, (4) investigating how enzymes and microbes interact with pretreated cell walls, and (5) testing strategies for using pure or mixed microbial cultures for biomass deconstruction and conversion. An overarching goal is to integrate information obtained from these various investigations into comprehensive conceptual and computational models of cellulose deconstruction in both natural and engineered environments.

3. Characterization and Modeling

Characterization and modeling researchers apply and create advanced technologies to analyze chemical and structural changes that occur in modified plant cell walls. Switchgrass and poplar samples generated by BESC researchers will be catalogued, bar coded, and analyzed in detail for chemical composition at the National Renewable Energy Laboratory (NREL). From NREL, samples are passed along to other partner institutions for pretreatment and enzyme-digestibility studies.

Knowledge gained by thoroughly characterizing and modeling cell-wall synthesis pathways, biomass structure and composition, and microbe-enzyme interactions with biomass surfaces will drive the coordinated development of CBP microbes and new generations of switchgrass and poplar optimized for deconstruction. Combining characterization, modeling, and data sharing will help define the genomic and physical basis of plant cell-wall recalcitrance and deconstruction.

Translation of BESC Science into Commercial Applications
BESC has recruited internationally known academic and bioenergy industry leaders to serve on its board of directors. BESC also has formed a commercialization council of technology-transfer experts from the center’s partner institutions to evaluate the commercial potential of all new inventions arising from BESC research. BESC will host a BioEnergy Nexus forum that will bring together graduate students with innovative product ideas, bioenergy companies, venture capitalists, and other investors to catalyze new collaborations.

BESC’s home base will be less than 40 miles from the nation’s largest precommercial switchgrass-to-ethanol demonstration plant. The $40 million facility is funded by the Tennessee Biofuels Initiative and will be operational in 2009. The demonstration plant will be a useful resource for testing the commercial viability of switchgrass varieties and biofuel-processing technologies developed from the scientific discoveries of BESC and other research organizations.

Education and Outreach
By leveraging successful educational and training programs already in place at partner academic institutions, BESC will offer students, postdoctoral staff, and scientists interdisciplinary research opportunities that cut across a broad range of biofuel-related fields. To extend the reach of BESC science to diverse locations and communities, collaborative workshops for training students and scientists and an open seminar series reporting scientific progress will be held at each partner institution. BESC also will provide opportunities each year for non-BESC scientists to participate in research at one or more partner sites. Announcements about BESC outreach and educational programs and employment opportunities will be posted on the BESC website.

Lead Institution: Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee

Principal Investigator: Martin Keller

BESC Partners:

• DOE’s Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee (lead institution): DOE’s largest science and energy laboratory, ORNL is a world leader in poplar genome research, with strong programs in bioenergy research and plant and microbial systems biology. The ORNL Spallation Neutron Source and supercomputers at the ORNL National Leadership Computing Facility will be used to investigate and simulate the activity of enzyme complexes.
• Georgia Institute of Technology, Atlanta: Georgia Tech’s Institute for Paper Science and Technology provides BESC with expertise in biochemical engineering and instrumentation for high-resolution analysis of plant cell walls.
• DOE’s National Renewable Energy Laboratory (NREL), Golden, Colorado: NREL has nearly 30 years of experience in biomass and biofuel research and houses premiere facilities for analyzing biomass surfaces. NREL also has a long and successful history of establishing biofuel pilot plants and partnering with industry for commercial development of technologies.
• University of Georgia, Athens (UGA): UGA’s Complex Carbohydrate Research Center maintains state-of-the-art instrumentation for studying the structures of complex carbohydrates and the genes and pathways controlling plant cell-wall biosynthesis.
• University of Tennessee, Knoxville (UT): UT conducts successful programs in bioenergy-crop genetic and field research (particularly switchgrass) and biotechnological applications of environmental microbiology.
• Dartmouth College, Hanover, New Hampshire: Dartmouth’s Thayer School of Engineering is a leader in the fundamental engineering of microbial cellulose utilization and consolidated bioprocessing approaches.
• ArborGen, Summerville, South Carolina: ArborGen is a global leader in genetic forest research, development, and commercialization.
• Verenium Corporation, Cambridge, Massachusetts: Verenium is a biofuels-focused biotechnology company and developer of high-performance specialty enzymes found in diverse natural environments and optimized for targeted applications.
• Mascoma Corporation, Boston, Massachusetts: Mascoma is a leader in developing advanced bioprocessing technologies and establishing cellulosic ethanol production facilities.
• The Samuel Roberts Noble Foundation, Ardmore, Oklahoma: This nonprofit organization is devoted to improving agricultural production and advancing the development of switchgrass and other grasses through genomic research.
• Individual researchers from the University of California, Riverside; DOE Brookhaven National Laboratory (Upton, New York); Cornell University (Ithaca, New York); Virginia Polytechnic Institute and State University (Blacksburg, Virginia); University of Minnesota (St. Paul, Minnesota); and Washington State University (Pullman, Washington) specialize in biomass pretreatment, characterization of plant-associated microbes, cellulose and enzyme modeling, consolidated bioprocessing, and lignin biochemistry.

Location of Center: ORNL Campus, Oak Ridge, Tennessee

Funds / Support From Other Sources:

• $24.6 million from the state of Tennessee, including $11.6 million for building to house Center, $3 million for dedicated research equipment, $10 million for research, and $3-5 million for three faculty positions supporting bioenergy research
• An additional $40 million from the state of Tennessee for a 5 million gal/year demonstration-scale facility to be completed in 2009
• $5 million from Mascoma Corporation to support collaborative research
• $6 million of equipment funds from the Georgia Research Alliance: $3M for equipment, $3M for faculty
• $500,000 in cost share support from Virginia Tech University