Metabolic Engineering for the Production of Medium-Chain Fatty Acids and Derivatives in Baker's Yeast

Medium-chain fatty acids (MCFAs, with carbon chain length of 6 to12) and their derivatives are valuable compounds which can be used as food additives, anti-pathogenic agents, nutraceuticals, and drop-in fuels. Thus, they are very attractive target compounds for microbial bioproduction. In this study, we aimed to metabolically engineer baker’s yeast to produce MCFAs and their derivatives. We enhanced the metabolic flux towards MCFA production by using combinatorial metabolic engineering approaches, including competitive pathway engineering, heterologous pathway reconstitution, and cofactor supply engineering. Blocking of competitive pathways to MCFA biosynthesis by multi-gene deletion led to significant accumulation of C8-C12 fatty acids as well as long-chain fatty acids. Further enhancement in MCFA production was achieved by introduction of a mammalian MCFA biosynthesis pathway into the MCFA-accumulating mutant. Subsequently, we demonstrated the conversion of MCFAs into valuable compounds by reconstituting and functionally characterizing a dietary lipid biosynthesis pathway in the MCFA-producing strain. Our findings could shed new light on metabolic engineering for developing microorganisms for the production of valuable fatty acids and derivatives. Additionally, the obtained MCFA-producing yeast strains could be applied to produce other value-added compounds.