A plant malonyl-CoA synthetase enhances lipid content and polyketide yield in yeast cells

Malonyl-CoA is the essential building block of natural products such as fatty acids, polyketides, and flavonoids. Engineering the biosynthesis of fatty acids is important for biofuel production while that of polyketides provides precursors of medicines and nutritional supplements. However, microorganisms maintain a small amount of cellular malonyl-CoA, which could limit production of lipid and polyketides under certain conditions. Malonyl-CoA concentration is regulated by multiple pathways and signals, and changes in intracellular malonyl-CoA often lead to complex alterations in metabolism. In the present work, overexpression of a plant malonyl-CoA synthetase gene (AAE13) in Saccharomyces cerevisiae resulted in 1.6- and 2.4-fold increases in lipid and resveratrol accumulation simultaneously. We also demonstrated that AAE13 partially complemented the temperature-sensitive acc1 mutant, replacing this key enzyme in central metabolism. Mechanistic analysis by CoA quantification and transcriptomic measurement suggested that increases in malonyl-CoA concentration were coupled with drastic reductions in other major CoA compounds and clear suppression of tricarboxylic acid cycle-related genes. These results suggest that malonyl-CoA is a critical target for fatty acid and polyketide engineering and that overexpression of malonyl-CoA synthetic enzymes needs to be combined with upregulation of CoA synthesis to maintain metastasis of central metabolism.