Ethanologenic/Electricigenic Consolidated Biprocessing of Cellulosic Biomass

Energy usage will continue to increase at a dramatic pace for the foreseeable future, endangering the security, economy, and environment of the nation. One means of meeting this challenge is the replacement of liquid transportation fuels based on petroleum with cellulosic bioethanol. However, cellulosic ethanol remains too costly to be commercially feasible, in part due to the generation of organic acids that inhibit ethanol fermentation. This project will couple cellulolytic, ethanologenic, and electricity generating (electricigenic) bacteria in a process that eliminates these inhibitory organic acids, enhances ethanol production, and generates electricity. The cellulolytic and ethanologenic bacteria will hydrolyze the cellulose and hemicellulose fractions of lignocellulose, and produce ethanol and inhibitory organic acids. The acids produced by the fermentative bacteria, and during the pretreatment of the biomass (e.g. corn stover), will then be consumed by the electricigenic bacteria in a microbial fuel cell component of an ethanologenic/electricigenic bioreactor. Phase I will determine the feasibility of using this combined microbial process. Phase II will involve improvement and scale-up of the process. Commercial Applications and other Benefits as described by the awardee: A procedure that produces bioethanol and biopower less expensively and more efficiently should prove to be highly marketable. Cellulosic ethanol could replace up to 40 percent of the nation¿s petroleum-based liquid fuels, instead of the 2 percent that may be replaced by grain-based alcohol.