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

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。

In order to enhance the yield of dextran dextrinase （DDase） produced by Gluconobacter oxydans DSM 2003, the effects ofpH 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 with-out 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.