(752b) Non-Growth Metabolism in Synthetic Auxotrophic Knockouts of Escherichia coli for Chemical Production

Decoupling growth and production phases in microbial cell factories to limit carbon loss to biomass is of substantial interest to improve product yields. However, E. coli that stop growing due to a stress (e.g. nitrogen limitation) have drastically reduced overall metabolism. Therefore, deregulating non-growth metabolism is essential to achieving efficient stationary phase chemical production. We have evaluated the effect of metabolic gene deletions on central carbon metabolic regulation. We have investigated non-growth conditions that have enhanced glucose uptake rates compared to stationary phase cells. We want to further understand these metabolic changes to identify regulatory bottlenecks in central carbon metabolism for future strategies to increase non-growth metabolism and divert carbon to valuable products. To do so, a robust analysis pipeline must be in place including: rapidly quenching metabolism, derivatization of metabolites for GC-MS analysis, design of quality control procedures, and benchmarking available software packages to correctly identify and quantify each metabolite. We have used this platform to characterize synthetic auxotrophic knockouts of E. coli, and have investigated chemical production in select strains. This metabolomics platform is generally useful to inform strain engineering strategies to improve yields and productivities for the biosynthesis of a wide range of different chemicals and fuels.