Biomass recalcitrance is the central theme at BESC. Using innovation and understanding to overcome this barrier will lead to multiple benefits.
The key barrier to realizing the considerable benefits of cellulosic biofuels is the availability of cost-effective technology to overcome the difficulty of converting lignocellulosic feedstocks to reactive intermediates--"recalcitrance" of cellulosic biomass. In the continued presence of this barrier, producing new products from established bioenergy feedstocks will do little to advance broader societal goals, since energy security and economic development impacts are largely feedstock-determined rather than product-determined. Removal of this barrier will enable production of a broad range of biofuels and other commodity products, of which ethanol will likely be the first to be commercialized.
Cellulosic biomass can be converted to fuels by a variety of routes, including (1) thermochemical processes involving reactive intermediates other than sugars (e.g., synthesis gas and pyrolysis oil), (2) fermentative processes that overcome recalcitrance primarily by nonbiological means (e.g., acid hydrolysis, phosphoric acid swelling, and ionic liquid pretreatments), and (3) fermentative processes that overcome recalcitrance with key biotechnology-driven advances. The Department of Energy's (DOE) BioEnergy Science Center (BESC) is convinced that the third approach—particularly the development of less recalcitrant plants and/or microbes that more effectively convert lignocellulose—is the most promising approach to overcome the recalcitrance barrier.
BESC's targeted focus on recalcitrance is singular among the three DOE Bioenergy Research Centers (BRCs) and comparable institutions worldwide. Prior to the formation of the BRCs, BESC scientists led the recognition and definition of the recalcitrance barrier. BESC has redefined the fundamental and applied frontiers of the biomass recalcitrance field by gaining seminal insights into the synthesis of plant cell walls and the mechanisms of recalcitrance, proving that plants can be modified to be substantially less recalcitrant, and demonstrating that solubilization of plant cell walls is far more effective when mediated by cellulolytic microbes than by cell-free enzymes. In light of these considerations, BESC is confident that success in developing cost-competitive cellulosic biofuels is achievable and that BESC will make a critical contribution to addressing the nation's pressing energy challenges by continuing to focus on the Center's defining goal: To enable the emergence of a sustainable cellulosic biofuels industry by leading advances in science and science-based innovation resulting in removal of recalcitrance as an economic barrier.
As a result of the advances BESC has made to date, its cross-disciplinary and cross-institutional foundation, and the Center's singular thematic focus, BESC is in a unique position to:
- Bring to fruition the world's most comprehensive efforts aimed at advancing understanding of the fundamentals of the multiple dimensions of recalcitrance.
- Develop and field-test less recalcitrant biomass feedstocks.
- Realize the potential of microbial cellulose utilization.
This series of developments will include an unprecedented opportunity to examine the combined benefits of plants and microbes engineered to overcome recalcitrance, and to evaluate milder biomass pretreatments that are tuned to the properties of new feedstocks and biocatalysts. The current progress and potential future contributions are facilitated by an integrated management organization that has assembled the best scientists in each of the outlined disciplines from across multiple institutions.