Overcoming the recalcitrance of cellulosic biomass is the dominant obstacle to cost-effective production of biofuels capable of impacting U.S. consumption of fossil transportation fuels. The BioEnergy Science Center (BESC) is addressing this challenge with an unprecedented interdisciplinary team combining national lab, university and industrial researchers as described at www.bioenergycenter.org.
BESC is addressing (1) targeted modification of plant cell walls to reduce their recalcitrance (using Populus and switchgrass as high-impact bioenergy feedstocks), thereby decreasing or eliminating the need for costly chemical pretreatment; and (2) consolidated bioprocessing, which involves the use of a single microorganism or microbial consortium to overcome biomass recalcitrance through single-step conversion of biomass to biofuels.
This update will highlight BESC achievements from the first two years of the Center.  To determine the chemical, structural, and genetic features that make cellulosic biomass recalcitrant, BESC has developed a high-throughput characterization pipeline that integrates advanced technologies for compositional analysis, pretreatment, and enzyme digestibility studies. BESC now can compare hundreds of samples to determine which plant genes impact cell-wall compositional and structural changes that affect enzyme deconstruction.  This characterization pipeline is being utilized for both natural variants of switchgrass and Populus as well as transgenic variants.  Building on earlier work, one of the first genes in switchgrass that we modified has resulted in a 25% increase in ethanol production after pretreatment and fermentation.  We are also developing and utilizing improved skills to manipulate thermophilic cellulolytic microbes which are showing complex behaviors as they interact and degrade the biomass.