Biosynthesis of keto acids by fed-batch culture of Yarrowia lipolytica WSH-Z06.

Both α-ketoglutarate (α-KG) and pyruvate (PYR) are important organic acids with promising applications in the food, pharmaceutical and chemical industries. During the production of α-KG by different microorganisms, PYR is always present as a by-product. Strategies have been applied to eliminate PYR accumulation since it can bring difficulties to the downstream separation process. However, modern separation technologies have already conquered this problem. Therefore, this study was aimed at simultaneously enhancing α-KG and PYR production by Yarrowia lipolytica WSH-Z06. Using a fed-batch strategy, in which the initial glycerol concentration was 50g·L-1, the residual glycerol concentration was maintained 20-30g·L-1 by constant feeding at a rate of 1.25g·L-1·h-1. The titers of α-KG and PYR were increased by 9.6% and 176.8%, and reached 67.4g·L-1 and 39.1g·L-1, respectively. The final yield of keto acids was 0.71g·g-1 glycerol, which is 42.0% higher than that of the optimal batch fermentation.