产纳豆激酶的枯草芽孢杆菌基因工程菌发酵条件的响应面优化

采用实验室前期构建的能够高产纳豆激酶的枯草芽孢杆菌基因工程菌株，对其液体发酵条件进行优化。通过单因素实验和响应面Box-Behnken模型优化液体发酵培养参数，五因素三水平的响应面分析表明最佳发酵培养条件为:蛋白胨26.05 g/L，葡萄糖29.29 g/L，MgSO4 1.5 g/L，CaCl2 0.74 g/L，NaCl 10 g/L，pH 9.0，接种量3 %。在最优发酵培养条件下，纳豆激酶最高酶活达到2 186.17 IU/mL，比优化前提高了269 % ，这表明响应面法优化枯草芽孢杆菌工程菌能够明显的提高纳豆激酶活性，为该菌株规模化生产纳豆激酶提供了基础应用参考。

Optimization of Fermentation Conditions for Nattokinase Production by Genetically Engineered Bacillus Subtilis Using Response Surface Methodology

A strain of Bacillus subtilis genetically engineered with high yield of nattokinase was previously prepared. Its liquid fermentation conditions were optimized by single factor experiment and response surface methodology （RSM） Box-Behnken model in the present work. The results of five-factor and three-level response surface analysis show that the optimal fermentation conditions are obtained at peptone of 26.05 g/ L， glucose of 29.29 g/L， MgSO4 of 1.5 g/L， CaCl2 of 0.74 g/L， NaCl of 10 g/L， pH of 9.0， and inoculation amount of 3%， the highest enzyme activity of nattokinase reaches 2 186.17 IU/mL， 269% higher than the one before optimization. It indicates that response surface methodology can effectively improve the activity of nattokinase， which provides a basic application reference for the production of nattokinase.