Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 28, 2008
Publication Date: N/A
Technical Abstract: One of the technical challenges for biomass conversion to ethanol is the generation of inhibitors during biomass pretreatment that interfere with microbial growth and subsequent fermentation. These inhibitors are formed in dehydration of pentoses and hexoses derived from degradation of cellulose and hemicellulose biomass, and caused by complex chemical conversions of biomass pretreatment. Inhibitors furfural and 5-hydroxymethylfurfural (HMF) are commonly encountered in biomass hydrolysate, especially for those treated by economic acid hydrolysis. Removal of these toxic compounds prevents cost-efficient biomass conversion to ethanol. We conduct functional genomic studies for microbial stress tolerance for low-cost bioethanol production. Our research covers both basic and applied science. Using directed genomic adaptation and protein engineering approaches, we created tolerant ethanologenic yeast Saccharomyces cerevisiae NRRL-Y-50049 and numerous tolerant strains that can in situ detoxify biomass conversion inhibitors such as furfural and HMF. Our newly generated tolerant yeast strains are the first available that can be used as an initial culture to detoxify the inhibitors while producing ethanol. Fermentation based bioprocess including economic biomass conversion to ethanol relies extensively on microbial performance. Application of these tolerant ethanologenic yeast strains provides benefits of reduced production cost and simplified fermentation procedures for comprehensive utilization of low-cost biomass feedstocks. Mechanisms of tolerance and detoxification of the inhibitors will be addressed.