Enhanced α-ketoglutaric acid production in Yarrowia lipolytica WSH-Z06 by an improved integrated fed-batch strategy

This study aimed at enhancing alpha-ketoglutaric acid (alpha-KG) production by Yarrowia lipolytica WSH-206. Batch culture experiments demonstrated that CaCO3 and a relatively low pH (3.0) in the alpha-KG production phase contributed to alpha-KG synthesis. Using a two-stage pH control strategy, in which pH was buffered by CaCO3 in the growth phase and then maintained at 3.0 in the alpha-KG production phase, the yield of alpha-KG reached 53.4 g L-1. In the later phase of batch fermentation, the glycerol was exhausted but synthesis of alpha-KG did not cease. Therefore, glycerol was fed with an integrated fed-batch mode, and alpha-KG production increased to 66.2 g L-1 with a productivity of 0.35 g L-1 h(-1). Compared to optimal batch culture, alpha-KG production and productivity were enhanced by 23.9% and 16.7%, respectively. The two-stage pH control strategy, constant feeding approach and lower pH in later phase would be useful for alpha-KG industrial production. (C) 2012 Elsevier Ltd. All rights reserved.