响应面法优化萎缩芽孢杆菌BsR05发酵培养基

为了提高萎缩芽孢杆菌Bacillus atrophaeus BsR05发酵液的芽孢产量,采用响应面法对BsR05发酵培养基的最佳工艺条件进行了优化。通过Plackett-Burman实验,筛选出玉米粉、(NH_4)_2SO_4和MgSO_4·7H_2O为影响产孢的主要因子。采用最陡爬坡路径法确定3个因素的响应中心点及最适浓度范围,最后,通过Box-Behnken设计建立主要培养基成分与芽孢产量之间的回归关系,并确定发酵培养基最佳配方为葡萄糖5 g/L、玉米粉15.9 g/L、豆粕40.0 g/L、K_2HPO_4 3.0 g/L、KH_2PO_4 1.0 g/L、(NH_4)_2SO_4 2.1 g/L、MgSO_4·7H_2O 0.40 g/L、MnSO_4 0.02 g/L。经重复实验验证,平均芽孢含量与预测芽孢含量基本一致,发酵液中BsR05的芽孢产量从优化前的4.73×10~9 CFU/m L提高到6.02×10~9 CFU/m L。

Optimization of fermentation medium composition for Bacillus atrophaeusBsR05 by response surface method

To increase the spore production of Bacillus atrophaeus BsR05, a response surface method was applied to optimize the technological conditions of BsR05 fermentation medium. Corn flour, (NH4)2SO4 and MgSO4·7H2O were selected as the major factors affecting sporulation by means of Plackett Burman design. The method of steepest ascent path was adopted to determine the response center and the optimal concentration range of these 3 factors. Finally, the regression relationship between the main medium composition and the spore yield was established by Box Behnken design. The optimal formula for the fermentation medium was determined as follow：glucose 5 g/L，corn flour 15.9 g/L, soybean meal 40 g/L, K2HPO4 3.0 g/L, KH2PO4 1.0 g/L, (NH4)2SO4 2.1 g/L, MgSO4·7H2O 0.40 g/L and MnSO4 0.020 g/L. After repeated experiments, it was verified that the average spore content was basically consistent with the predicted spore content, and the concentration of the spore was increased from 4.73×109 CFU/mL to 6.02×109 CFU/mL after the optimization.