pH对L-天冬酰胺酶发酵的影响及其控制

Influence of pH Value on Fermentation of L-asparaginase and Control

pH对大肠杆菌L-天冬酰胺酶的产生有很大的影响。通过对不同缓冲体系试验和对摇瓶发酵过程pH变化的分析,了解摇瓶发酵过程中pH对L-天冬酰胺酶合成的影响。采用流加磷酸自控L-天冬酰胺酶发酵过程的pH,可延长发酵周期,有效地防止菌体的过早自溶,大大促进L-天冬酰胺酶的合成,较分批发酵提高产酶 83%,达到 110u/mL。发酵动力学特性分析表明,该发酵方式L-天冬酰胺酶的合成与菌体生长不相关,控制比生长速率μ为 0. 15~0. 30h-1,均有利于L-天冬酰胺酶的合成,可使比产酶速率的最大值Qpmax达到 3 922u/(g·h)。

The influence of pH value on the fermentation of L-asparaginase is extremely significant. The influence of pH value on the synthesis of L-asparaginase during fermentation was studied under various buffers and the change of pH value in the the shaked flask. The pH value during fermentation was controlled by feeding phosphoric acid automatically. It prolonged the fermentation period, effectively prevented the premature autolysis of cells and significantly accelerated the synthesis of L-asparaginase. The yield of L-asparaginase (110 u/mL) increased by 83% compared with that by batch fermentation. Fermentation kinetics indicate that the synthesis of L-asparaginase is not related to the growth of bacteria. When the specific growth rate of bacteria was controlled at 0.15~0.30 h^(-1), the Q_(p_(max ))reached 3 922 u/(g·h).