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摘要
The effects of culturing conditions on phenylalanine ammonia lyase production by a recombinant E. coli strain were investigated by using a controlled fed-batch fermentation system. In a 5 L fermentor, the optimal composition of the batch medium was 2% glucose, 1% yeast extract, 0.7% K(2)HPO(4), 0.8% KH(2)PO(4), 0.5% (NH(4))(2)SO(4), 0.1% MgSO(4)center dot 7H(2)O. The optimal feed glucose solution was 50%. Glucose concentration and pH of the culture broth were maintained at about 2.0 g/L and 7.0 during the fed-batch phase, respectively. Following 24-h cultivation, 0.2 mmol/L isopropyl-beta-D-thiogalactopyranoside (IPTG) was added and temperature was shifted from 37 degrees C to 42 degrees C to induce pal gene expression. Under optimal conditions, a high productivity of 300 U/g could be achieved after 48 h culture, and a cell density of OD(600) about 82 was obtained at 52 h culture at 500 r/m stirrer speed and 1 vvm, respectively.
- 出版日期2009-3
- 单位河北大学
