(531c) The Effects of ΑFΕΧ Pretreatment on the Fermentability of Lignocellulosic Hydrolysates Using Escherichia Coli KΟ11

Ming Woei Lau, Balan Venkatesh and Bruce E. Dale Biomass Conversion Research Laboratory, Department of Chemical Engineering and Materials Science, 3246 Engineering Building, Michigan State University, E. Lansing, MI ? 48824

Lignocellulosic bioethanol offers us several advantages in terms of economic development, energy security and environmental protection. Unfortunately, the complex nature of lignocellulosic plant material poses significant challenges to pretreatment, hydrolysis and downstream processing. In particular, the composition of biomass and pretreatment conditions dictate the products formed, including potential sugar degradation products. The presence of products such as furfural, hydroxylcarboxylic acids and acetic acid strongly influence the fermentability of a hydrolysate. We are investigating the fermentability of hydrolysate from Ammonia Fiber Explosion (AFEX) treated corn stover at industrial relevant concentrations. The effects of various detoxification procedures such as overliming and adsorbent conditioning are evaluated. Furthermore, AFEX pretreatment is suspected to be a nutrient addition process via the residual ammonia on treated material. We are evaluating the effects of this residual ammonia on fermentation. The feasibility of simultaneous saccharification and co-fermentation with Escherichia coli KO11 using AFEX-treated corn stover and commercial hydrolytic enzymes is explored. To draw appropriate comparisons, hydrolysate from acid treated corn stover is analyzed concurrently with hydrolysates from AFEX treated stover. These studies and comparisons will help elucidate the effects pretreatment methods on hydrolysate fermentability and process economics.