11-45: Engineering of consolidated bioprocessors capable of cellulosic ethanol production

Cellulosic biofuels represent a powerful alternative to petroleum.  However the economic viability of cellulosic biofuels requires overcoming multiple challenges, including the recalcitrance of cellulosic biomass to enzymatic degradation. Recent studies suggest a key approach to lowering the cost of biofuels is using consolidated bioprocessing. Consolidated bioprocessing involves the endowment of a single organism with the ability to degrade biomass to its component sugars, and to catalyze their fermentation to biofuel.

Research within the Great Lakes Bioenergy Research Center (GLBRC) involves multiple approaches to develop consolidated bioprocessors.  First, we have developed pipelines for discovery of bacterial enzymes that efficiently degrade biomass, combined with biochemical characterization of these enzymes, and their transplantation into ethanologenic organisms. We have developed liquid and solid screening technologies that facilitate the rapid identification of bacteria capable of biomass degradation. We have used these methods to identify novel biomass utilizing strains, whose genomes are expected to be a rich source of degradative enzymes. We have also used these screening approaches to characterize the ability of known cellulose-degrading organisms to degrade biomass substrates critical to the GLBRC. Genes obtained from these biomass-degrading organisms have been used to develop first generation strains capable of the conversion of cellulose to ethanol. Second, we have developed versatile genetic tools for the engineering of diverse organisms capable of biomass degradation. Using these tools we are currently identifying genes critical for biomass breakdown, as well as evaluating the capabilities of these strains as consolidated bioprocessors.