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

This study aimed at enhancing α-ketoglutaric acid (α-KG) production by Yarrowia lipolytica WSH-Z06. Batch culture experiments demonstrated that CaCO3 and a relatively low pH (3.0) in the α-KG production phase contributed to α-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 α-KG production phase, the yield of α-KG reached 53.4 g L−1. In the later phase of batch fermentation, the glycerol was exhausted but synthesis of α-KG did not cease. Therefore, glycerol was fed with an integrated fed-batch mode, and α-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, α-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 α-KG industrial production.