氧化葡萄糖杆菌合成右旋糖酐糊精酶的pH两阶段控制策略

Two-stage pH control strategy of dextran dextrinase production by Gluconobacter oxydans DSM 2003

摘要:

为了进一步提高氧化葡萄糖杆菌右旋糖酐糊精酶的产量, 在3 L发酵罐水平上考察了pH (3.5?6.0)对菌体生长和产酶的影响。基于不同pH发酵过程中菌体生长及产物合成的变化, 确定了pH两阶段控制策略, 即0?6 h时控制pH 5.0, 6 h后将pH调至4.0。通过采用这一优化策略, 右旋糖酐糊精酶酶活有了较大的提高, 可达4.03 U/mL, 比不控制pH模式下提高了38.5%, 是摇瓶水平的12.5倍, 同时发酵时间从47 h缩短为15 h。

Abstract:

In order to enhance the yield of dextran dextrinase (DDase) produced by Gluconobacter oxydans DSM 2003, the effects of pH from 3.5 to 6 on cell growth and DDase activity were investigated in a 3 L fermentor. Based on time courses of cell growth and DDase activity, we developed a two-stage pH control strategy, in which pH was controlled at 5.0 for the first 6 h and then 4.0 for remaining time. Under the optimized strategy, the production of DDase had a significant improvement. Moreover, the maximal DDase activity reached 4.03 U/mL, 38.5% and 1 147% more than that from the strategy without pH control and in the 250 mL shake flasks, respectively. Meanwhile, the fermentation time of DDase in the fermentor was also shortened from 47 h to 15 h compared to that in 250 mL shake flasks.