Control of acetic acid metabolism of recombinant Yarrowia lipolytica for efficient succinic acid production

Abstract

Succinic acid is a high value-added organic acid widely used in food, chemical and pesticide industries. As a new robust non-conventional yeast, Yarrowia lipolytica attracts more and more attention due to its potential for industrial applications. Previously, we obtained a succinic acid-producing strain through gene deletion of succinic acid dehydrogenase subunit encoding gene Ylsdh5, resulting in the strain of PGC01003. However, the recombinant strain produced large amount of acetic acid due to imbalance between glycolysis and TCA cycle which hindered the efficient production of succinic acid. PDH bypass was interfered to decrease the overflow of acetic acid and produce succinic acid under natural pH. Acetic acid was reduced to 4.6 g/L through heterologous expression of acetyl coenzyme A synthase from Salmonella enteric, which was 75.4% of the control strain. Deletion of CoA-transferase gene Ylach1 eliminated acetate formation and improved succinic acid production, and the resulting strain produced as high as 7.0 g/L succinic acid. Our study provides foundation for further construction of efficient cell factory of succinic acid production.