Development of an E. coli Co-Culture for the Improved Conversion of Phenylpropanoic Acids to Catechins in Vivo

The field of metabolic engineering has equipped scientists with the ability to harness the power of biology to produce a wide variety of difficult to synthesize plant natural products at high titers, yields, and productivities. The high-titer microbial synthesis of these compounds is possible through the careful optimization of both internal genetic elements and external fermentation conditions. Although, recent advances have shown highly efficient production to be possible, many systems still result in non-industrially feasible titers. This less than desirable production is, in part, due to the high metabolic burden of expressing extensive extrinsic pathways in a single microbial strain. This work attempts to reduce the metabolic stresses associated with expressing the 6-gene catechins pathway by separating the burden of pathway over-expression across two E. coli strains in co-culture. Using this method, we demonstrate up to a 400-fold improvement in the titer of green tea catechins over previous literature reports. These results highlight the potential for the use of co-culture methods to further improve microbial production of plant natural products in E. coli.