(567al) Genetic Screens and Selections for the Production of Fatty Acids

Fatty acid derivatives are promising biofuel candidates as they have numerous desirable properties and can be readily produced by microbial hosts. Recent improvements in the production of fatty acids from Escherichia coli have been the result of rational modifications its well-studied fatty acid biosynthesis pathway. Further improvements in fatty acid production will likely stem from strain improvement strategies involving genetic screens and selections.

Genetic screens and selections are powerful methods for identifying members of a population that display a desired phenotype. While selections for microorganisms with increased tolerances to extreme environments are relatively straightforward, screens or selections for the production of a specific small molecule, such as a fatty acid, are more challenging. The key to the successes of these efforts are tools that somehow link the presence of a desired small molecule to a detectable phenotype.

Here we present a novel tool capable of detecting the elevated production of long chain fatty acids (LCFA) in E. coli. This tool, derived from the regulatory system utilized by Pseudomonas aeruginosa to detect and respond to LCFA, can be readily integrated into existing strain improvement strategies to screen or select for the production of LCFA. Specifically, our tool was employed in tandem with TRackable Multiplex Recombineering (TReMR), a genome-wide strain improvement technique developed by the Gill Lab that utilizes advances in DNA synthesis and genomics to rapidly identify the genetic basis for a complex phenotype. Results of our genetic screens and selections for the improvement of LCFA production in E. coli will be presented.