枯草芽孢杆菌L07产中性蛋白酶发酵条件优化

Optimization of fermentation conditions for the production of neutral protease by Bacillus subtilis L07

该文对枯草芽孢杆菌L07产中性蛋白酶的发酵培养基和发酵条件进行了优化。通过单因素实验探究蔗糖、蛋白胨、吐温-80、MgSO4、初始pH、接种量、发酵时间和发酵温度这8个因子对枯草芽孢杆菌L07产中性蛋白酶的影响。利用Plackett-Burman实验进行筛选,确定主要显著影响因子为蛋白胨、MgSO4和接种量。最陡爬坡实验确定下一步响应面实验的中心点为接种量13 mL/100mL、蛋白胨含量15 g/100mL,MgSO4含量0.4g/100mL。最后通过Box-Behnken实验确定最佳发酵条件是蔗糖10 g/100mL、蛋白胨15.3 g/100mL、吐温-800.2 mL/100mL、初始pH6.8、MgSO4 0.39 g/100mL、接种量13.4 mL/100mL、发酵温度32℃、发酵时间44 h,在此发酵条件下理论预测枯草芽孢杆菌L07产中性蛋白酶酶活力为401.005 U/mL,实测值达到401.83 U/mL,比最初优化前133.42 U/mL提高了2.01倍。

The fermentation conditions of neutral protease production by Bacillus subtilis L07 were optimized in this study. The effects of sucrose,peptone,Tween-80,MgSO4,initial pH,inoculation amount,fermentation time and temperature on the neutral protease production were investigated by single factor experiments. Using Plackett-Burman experiment,the main significant factors were identified as peptone,magnesium sulfate and inoculation amount. The steepest ascent experiment determined the center point of the next response surface experiment was 13 mL/100 mL of inoculation,15 g/100 mL of peptone,and 0. 4 g/100 mL of MgSO4. Finally,the optimal fermentation conditions were determined through Box-Behnken experiments: sucrose 10 g/100 mL,peptone 15. 3 g/100 mL,Tween-80 0. 2 mL/100 mL,initial pH 6. 8,MgSO4 0. 39 g/100 mL,inoculation volume 13. 4 mL/100 mL,and cultured for 44 h at 32 ℃ . Under these fermentation conditions,the neutral protease activity was increased from 133. 32 U/mL to 401. 83 U/mL.