纳豆激酶发酵条件的优化

利用Plackett-Burman 方法对影响纳豆芽孢杆菌液体发酵的各因素进行评价，筛选出对产纳豆激酶有显著效应的主要因素是豆饼粉浓度。在此基础上，用响应面分析法对发酵培养基中的豆饼粉浓度、CaCl2 浓度、葡萄糖浓度进行优化。所得的最优培养基成分为葡萄糖 1%、豆饼粉 3%、KH2PO4 0.2%、K2HPO4·3H2O 0.26%、MgSO4·7H2O 0.1%、CaCl2 0.12%。拟合实验结果显示，纳豆激酶液体发酵液的酶活由初始培养条件的约1800U/ml提高到优化后的2226.06U/ml。

Optimization of Fermentation Conditions for Production of Nattokinase

This study aimed to optimize the fermentation conditions for nattokinase production by Bacillus subtilis Natto with response surface methodology. Firstly, Plackett-Burman design was used to evaluate the effects of related factors on nattokinase production. It was found that soybean powder concentration is the most signficant positive factor, followed by concentrations of glucose and CaCl2 (negative factor). And then, the concentrations of soybean powder, glucose and CaCl2 were further optimized using response surface analysis. Results revealed that the optimal medium constituents for liquid fermentation are as follows: glucose 1%, soybean powder 3%, KH2PO4 0.2%, K2HPO4·3H2O 0.26%, MgSO4·7H2O 0.1% and CaCl2 0.12%. The optimized conditions allow nattokinase production to increase from 1800 U/ml to 2226.06 U/ml.