11-39: Hydrolysis of switchgrass to soluble sugars using Clostridium phytofermentans and solid state fermentation

The hydrolysis of lignocellulosic biomass to soluble sugars remains the bottle neck in biofuels production. Most fermentation processes also involve significant amounts of water resulting in waste disposal issues. Therefore we are evaluating the use of solid state fermentation by anaerobic bacteria as a mechanism to provide a more cost effective and more efficient technology to convert biomass feedstocks, such as switchgrass, to relatively simple sugars. Clostridium phytofermentans, an anaerobic bacterium shown to utilize both hexose and pentose sugars, was grown on switchgrass in a microcosm to represent the solid state fermentation approach. The preliminary results showed that this bacterium grew as a biofilm and hydrolyzed the switchgrass to release reducing sugars. Hydrogen, carbon dioxide, ethanol and acetate were measured as the fermentation products. Research will continue using this approach to further evaluate the rate and extent that lignocellulosic biomass is converted to sugars that can subsequently be fermented to biofuels such as bioethanol.