Production of Polylactic Acid and its Copolymers by metabolically engineered Escherichia coli

Abstract

Polylactic acid (PLA) is a promising biomass-derived polymer, but is currently synthesized by a two-step process: fermentative production of lactic acid followed by chemical polymerization. Here we report production of PLA homopolymer and its copolymer, poly(3-hydroxybutyrate-co-lactate), by direct fermentation of metabolically engineered E. coli. In this study, the metabolic pathways of E. coli were further engineered based on in silico genome-scale metabolic flux analysis. Using this engineered strain, PLA homopolymer and P(3HB-co-LA) copolymers containing up to 70 mol% lactate could be produced up to 11 wt% and 46 wt% from glucose, respectively.