One-step fermentative production of poly(lactate-co-glycolate) from carbohydrates in Escherichia coli

Application of a systems metabolic engineering strategy enables production of poly(lactate- co -glycolate) (PLGA) and other non-natural polymers in Escherichia coli . Poly(lactate- co -glycolate) (PLGA) is a widely used biodegradable and biocompatible synthetic polymer. Here we report one-step fermentative production of PLGA in engineered Escherichia coli harboring an evolved polyhydroxyalkanoate (PHA) synthase that polymerizes D -lactyl-CoA and glycolyl-CoA into PLGA. Introduction of the Dahms pathway enables production of glycolate from xylose. Deletion of ptsG enables simultaneous utilization of glucose and xylose. An evolved propionyl-CoA transferase converts D -lactate and glycolate to D -lactyl-CoA and glycolyl-CoA, respectively. Deletion of adhE , frdB , pflB and poxB prevents by-product formation. We also demonstrate modulation of the monomer fractions in PLGA by overexpressing ldhA and deleting dld to increase the proportion of D -lactate or by deleting aceB , glcB , glcD , glcE , glcF and glcG to increase the proportion of glycolate. Incorporation of 2-hydroxybutyrate is prevented by deleting ilvA or feeding strains with L- isoleucine. The utility of our approach for generating diverse forms of PLGA is shown by the production of copolymers containing 3-hydroxybutyrate, 4-hydroxybutyrate or 2-hydroxyisovalerate.