Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/3/2007
Publication Date: N/A
Technical Abstract: The economics of fermentation-based bioprocesses rely extensively on the performance of microbial biocatalysts in industrial application. Development of yeast strains that can efficiently utilize heterogeneous sugars and withstand stress conditions in bioethanol conversion process is the key for sustainable, economic and cost-competitive lignocellulosic biomass conversion to ethanol. However, many of the industrially interesting microorganisms obtained thus far are not robust and unable to efficiently utilize diversified sugars derived from the biomass. We recently developed a tolerant ethanologenic yeast strain 12HF10 by directed evolutionary adaptation that in situ detoxified furfural and HMF and produced normal yield of ethanol in 48 hours while a wild type Saccharomyces cerevisiae control failed to establish a culture. Strain 12HF10 did not require a pre-build biomass but functioned as an initial inoculum to build a culture and complete the fermentation. Strains tolerant to HMF and able to use xylose were also obtained through the directed evolutionary adaptation method under laboratory settings. Based on documented yeast inner genetic potential, adaptation with desirable characteristics can be accomplished. Enhancement of genetic background of the ethanologenic yeast is needed as necessary by recombinant genetic engineering. The enhanced laboratory procedures significantly speed up biological evolutionary adaptation events to the stress condition and maintain the desirable ethanol production characteristics of the yeast. Studies on genomic mechanisms of the comprehensively integrated functions are under way. A comprehensive approach to genomic engineering will allow us to meet the challenges for efficient lignocellulosic biomass conversion to ethanol in a decade and beyond.