豆豉溶栓酶工程菌的发酵条件及重组溶栓酶的分离纯化

对豆豉溶栓酶工程菌株WB DFE5进行了摇瓶发酵条件的研究 ,确定了发酵的优化条件为 :可溶性淀粉 2 % ,酪蛋白 2 % ,大豆蛋白胨 0 5 % ,酵母粉 0 15 % ,K2 HPO40 2 5 % ,KH2 PO40 0 5 % ,CaCl2 0 0 2 % ,MgSO40 0 5 % ,pH7 0。通过硫酸铵分段盐析、离子交换和凝胶过滤 ,从 1L工程菌株WB DFE5的发酵液中分离纯化出 12 5mg重组豆豉溶栓酶 ,酶的比活为 5 918 7IU/mg。

Fermentation of Douchi Fibrinolytic Enzyme Gene Engineering Strain and the Purification of Recombinant Enzyme

In order to increase production of recombinant Douchi fibrinolytic enzyme(rDFE),the optimal fermentation conditions of recombinant Bacillus subtilise WB-DFE5 were determined. The compositions of culture medium are 2% soluble starch, 2% casein, 0.5% soybean peptone, 0.15% yeast extract, 0.25% K 2HPO 4, 0.05% KH 2PO 4, 0.02% CaCl 2, 0.05% MgSO 4, pH7.0. rDFE was purified by methods including ammonium sulfate fractional precipitation, SP-Sepharose FF, DEAE-Sepharose FF ion-exchang and Sephadex G-75 chromatography.12.5 mg of purified product was obtained from one liter of culture medium and the enzyme spectific activity is 5918.7IU/mg.