(69g) Engineering Biosynthesis and Applications of Medium-Chain Carboxylic Acids

Depleting oil reserves and growing environmental concerns have necessitated the development of new approaches to fuels and chemicals from renewable carbon sources. This talk will summarize my lab’s recent progress in metabolic engineering of E. coli for the sustainable production of C4-C6 carboxylic acids from glucose. Since these compounds are not native metabolites, we have designed an oxidation metabolic platform and engineered novel enzymes to enable the bio-based production. Furthermore, after several rounds of optimization, we have achieved high production titers. In particular, our engineered strains could biosynthesize C4 isobutyrate with a final concentration of 90 g/L. The concentration of C5 isovalerate could reach 32 g/L as well in a bioreactor. The success in fermentative manufacturing of C4-C6 acids provides a renewable approach to the synthesis of a variety of high-volume industrial chemicals. For example, isobutyrate is used to manufacture poly(methyl methacrylate); isovalerate is used to manufacture methyl isobutyl ketone.