溶氧对Candida glycerinogenes产甘油发酵过程的影响

研究了溶氧浓度对产甘油假丝酵母分批发酵生产甘油过程的影响。实验结果表明：当溶氧浓度控制在30%时，C. glycerinogenes的甘油产量、得率和产率达到最高，分别为120.7 g/L、0.575 g/g和1.69 g/(L•h)，而糖酵解代谢副产物形成最少。当溶氧浓度为10%时，发酵过程呈现出“巴斯德效应”的特征，生成的酵解代谢副产物维持在较高水平。在快速生长阶段，随着溶氧从10%增加到60%，细胞呼吸类型表现为从厌氧呼吸向好氧呼吸转变，酵解代谢副产物依次减少。在生长稳定期，控制的溶氧浓度越高，酵解代谢副产物乙醇、乙酸等的生成减少。分别选用Logistic方程、Luedeking-Piret方程和Luedeking-Piret-like方程，能较好地模拟细胞生长、甘油合成和葡萄糖消耗的动力学过程。

Effect of dissolved oxygen on glycerol production by Candida glycerinogenes

The influence of dissolved oxygen (DO) concentration, varied from10% (of air saturation) to 60%, on glycerol production by Candida glycerinogenes in the batch fermentation was investigated by using the chemically defined medium. The results showed that it was suitable for glycerol production by C. glycerinogenes at DO concentration of 30%, the glycerol concentration, yield and productivity were 120.7 g/L, 0.575 g/g and 1.69 g/(L•h), respectively, while the glycolytic by-products formation was the least. At DO concentration of 10%, the “Pasteur effect” arose during the whole fermentation process, so the glycolytic by-products could be kept a high level. During the rapid growth phase, the cells of C. glycerinogenes could gradually transit their anaerobic fermentation to aerobic metabolism and reduce the formation of glycolytic by-products when the DO concentration increased from 10 % to 60 %. However, the oxygen consumption of cells decreased sharply during the steady growth stage. With increasing DO concentration, the amounts of ethanol and acetic acid were gradually decreased. Logistic equation, Luedeking-Piret equation and Luedeking-Piret-Like equation were successfully applied to estimate the kinetics of cell growth, glycerol production and glucose consumption, respectively, under diverse DO concentrations.