Tuesday, May 1, 2012: 9:00 AM
Napoleon Ballroom A and B, 3rd fl (Sheraton New Orleans)
Consolidated bioprocessing (CBP) is a low-cost cellulosic biomass processing by integrating cellulase production, cellulose hydrolysis, and sugar fermentation into a single step. Although significant efforts have been made to create recombinant cellulolytic microorganisms, real recombinant cellulolytic microorganism that can produce sufficient secretory active cellulases, hydrolyze cellulose, and utilize soluble sugars for supporting cell growth and cellulase synthesis without organic nutrients is not available before our efforts (Engineering in Life Sciences 10, 398-406). We demonstrated that by using our high-level expression system the over-expression of Bacillus subtilis endoglucanase BsCel5 enables non-cellulose-utilizing Bacillus subtilis to grow on cellulose and pretreated lignocellulosic biomass as the sole carbon source without addition of costly organic nutrients (Metabolic Engineering, 13, 364-372). After directed evolution and screen on amorphous cellulose through a novel powerful and highly efficient enzyme engineering platform, both the expression/secretion level and specific activity of BsCel5 had been increased successfully (Microbial Biotechnology 4, 98-105). We also realized the optimization, co-expression and secretion of the most important family 5, 9 and 48 cellulases in a single B. subtilis strain. The one-step production of ethanol, biodiesel and lactate from cellulose and pretreated biomass in the minimal medium without adding any organic nutrient had been demonstrated. The recombinant cellulolytic B. subtilis would be an ultra-low-cost platform for producing biofuels and other value-added products from non-food biomass, with obvious advantages over other developing CBP microorganisms.