Process Simplification for Cellulose Conversion

The production of advanced biofuels from non-food cellulosic feedstocks requires the biomass to be pretreated and hydrolyzed to sugars that are fermented to ethanol or other molecules. The single major cost, other than feedstock, is the cost of enzyme. Consolidated bioprocessing (CBP) reduces the amount of enzyme needed, and therefore reduces enzyme costs through use of a genetically modified, pentose fermenting yeast that generates its own cellulolytic enzymes. CBP consolidates biochemical activities and fermentation capability into a single microorganism, and combines hydrolysis and formation of ethanol into a single unit operation, resulting in a simplified process with reduced costs. However, success with this approach also requires that biocatalyst inhibition due to phenolic compounds generated during the processing ligno-cellulosic biomass be overcome, and challenges caused by viscous slurries of pretreated cellulosic biomass be addressed. This talk presents chemical engineering applied to the direct fermentation of pretreated wood to ethanol and the engineering of processes that realize the benefits of CBP.