(620r) Engineer a Biosynthetic Platform to Branched Six- to Eight-Membered Lactones

Over the past several years, biological systems have been widely used for the sustainable production of several commodity chemicals, biofuels and more recently, for the production of bio-based polymers such as polylactic acid (PLA) and polyhydroxybutyrate (PHB). Although these bio-based polyesters show great potential, their stiff nature greatly limits their applications. As an alternative, substituted lactones have drawn great interest in the recent past as they generate a rubbery soft polymer block upon ring opening polymerization and further co-polymerization with hard PLA end blocks results in a triblock copolymer with mechanically tunable properties. Despite its numerous advantages, the ceiling temperature of six-membered lactone polymerization is around room temperature, making it unsuitable for hot melt polymerization. The goal of this project is to develop a biosynthetic platform in Escherichia coli for production of C6-C8 branched lactones. The advantage of higher lactones is that their higher ceiling temperature can allow high temperature polymerization reactions to be carried out directly in molds, thus avoiding the use of excess solvents.