Plant phenylpropanoid biosynthesis in Escherichia coli: engineering novel pathways and tools

Abstract

Plant phenylpropanoid natural products are important in the discovery of safe and effective therapeutics. Most plant natural products cannot be economically mass produced via extraction from plant tissue or chemical synthesis. In recent decades, engineering microbes to carry out the biosynthesis of plant natural products has emerged as a powerful technology. The goal of this thesis was to expand the capabilities of microbial biosynthesis of plant phenylpropanoids in <italic>Escherichia coli<italic> through exploring novel biosynthetic pathways and metabolic engineering tools. I first explored the biosynthesis of valuable lignans in <italic>E. coli<italic>, establishing random oxidative radical coupling through overexpression of a laccase and attempting to show stereoselective coupling by a dirigent protein. I also designed and built a biosynthetic pathway for rosmarinic acid, a valuable hydroxycinnamic acid ester, showed pathway bottlenecks and limitations, and identified future optimization strategies. I have also begun a project to better understand cargo protein encapsulation within bacterial microcompartments and to develop their utility as a means of spatially organizing metabolic pathways. This work has contributed significantly to the field of microbial metabolic engineering and has laid the groundwork for future economically viable production platforms.