(485k) Improving Escherichia Coli Ethanol Tolerance Using a Genome-Wide Approach

Engineered Escherichia coli has been shown to be a potential ethanologen for commercial cellulosic ethanol production with its ability to efficiently convert pentose and hexose sugars into ethanol. However, E. coli does not have the high native ethanol tolerance as other ethanologens such as S. cerevisiae and Z. mobilis. The objectives of this project are: (i) to identify genetic targets throughout the E. coli genome that improve ethanol tolerance, (ii) identify mechanisms of an ethanol tolerant phenotype in E. coli, and (iii) further engineer ethanol-tolerant E. coli strains. To identify genetic targets, we used a high-resolution genomic library approach called SCalar Analysis of Library Enrichments (SCALEs). We have performed selections for ethanol tolerance phenotypes upon E. coli K12 genomic libraries of varying and defined plasmid-based insert sizes. Using DNA microarray analysis, we identified the genetic elements that contribute to the ethanol tolerance phenotype with increased copy number. Data will be presented on the genetic targets found to confer improved ethanol tolerance with consideration of possible mechanisms responsible.