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

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.