ST1-08: Material balances for biochemical conversion of ammonia (AFEX), ionic liquid and dilute acid pretreated lignocellulosic biomass to fuels and chemicals

Thermochemical pretreatment is an essential step preceding biochemical conversion of lignocellulosic biomass to desired fuels and chemicals. An on-going collaboration between the three US-DOE funded bioenergy centers (i.e., GLBRC, JBEI and BESC) has given us a unique opportunity to compare corn stover pretreated by three different pretreatments (e.g., AFEX, ionic liquid and dilute acid) and test the biomass conversion using various combinations of commercial enzymes (e.g., Cellic enzyme series from Novozymes). An optimal combination of hydrolytic enzyme mixtures was defined for each pretreated substrate using the BCRL-microplate based hydrolysis assay method (Chundawat et al. 2008. High-throughput microplate technique for enzymatic hydrolysis of lignocellulosic biomass. Biotechnology and Bioengineering 99, 6, 1281-1294) for varying total protein loadings (5-60 mg/g glucan). Each substrate was hydrolyzed by the optimal combination of enzymes at high solids loading (18% solids loading or greater). A detailed compositional analysis was carried out for all pretreatment, enzymatic hydrolysis and fermentation processes based on the protocols established by previous CAFI studies (Wyman et al. 2005. Coordinated development of leading biomass pretreatment technologies. Bioresource Technology 96, 18:1959-1966).