| Currently, problems of low output, low substrate conversion rate and long fermentation cycle restricted the industrial production of α-ketoglutaric acid (α-KG) by Yarrowia lipolytica in large scale. A mutant strain, Y. lipolytica WSH-Z06 C3, with capacity of high output of α-KG, obtained in previous research was taken as starting strain to solve these three problems. Accumulation effects of rotating speed, calcium carbonate concentration, dissolved oxygen and feeding methods (multi node feeding and constant speed feeding) and other factors on α-KG with Y. lipolytica WSH-Z06 C3 were investigated in 50 L fermentor. The results showed that when the rotating speed was set at300 r/min, the concentration of α-KG and pyruvate reached 32.4 g/L and 19.66 g/L respectively. The output of α-KG was increased to 38.55 g/L, and pyruvate decreased to 8.28 g/L; when the concentration of calcium carbonate was at 20 g/L. The output of α-KG was further increased to 42.39 g/L with pyruvate at 6.22 g/L by controlling the level of dissolved oxygen at 50%. With the strategies of high initial glycerol concentration and different feeding methods investigated, it was found that the constant feeding mode had the best effect. The production of α-KG and pyruvate reached 66.27 g/L and 20.82 g/L, respectively. The output of α-KG and pyruvate increased 67.3% and 456%, respectively, as compared with the process before optimization, and provided considerable reference for industrial production of α-KG with Y. lipolytica. |
