(341d) Systematic and Recursive Engineering of E. Coli Using TReMR for Desired Tolerance to Acidic pH

TReMR is a novel genetic tool that utilizes a systematic and trackable approach for improvement of strains with a desired trait under a specific environment. We can monitor the response of microorganisms under certain circumstances by a genetic signal that is marked on each gene of the genome. Using TMR/TReMR, expression of each gene can be controlled positively or negatively. If the expression of a gene is helpful to survival and growth of the host strain under certain conditions, then the frequency of the strain with a beneficial trait increases compared to other strains with undesired traits. Based on these strategies and recombineering technique, we engineered E. coli for a desired trait, specifically pH tolerance herein, by recursive and multiple recombineering with control of each gene in the chromosome. This approach made it possible to engineer the strain systematically and efficiently. Engineered strain showed relatively high tolerance to acidic pH compared to wild type strain.