枯草芽孢杆菌生产抗菌物质的食品级发酵培养基优化

Optimization of Food-Grade Medium for the Production of Antibacterial Substances by Bacillus subtilis PNG27

为得到安全可靠的新型生物防腐剂,用枯草芽孢杆菌发酵食品同时提高其抗菌活性。采用单因素试验和Plackett-Burman试验设计筛选出4个关键因子为脱脂奶粉、番茄汁、发酵时间和发酵温度;使用Box-Behnken原理设计进行响应面试验确定出最佳培养基配方和发酵条件:小麦粉16.0 g/L、脱脂奶粉20.0 g/L、黄豆粉酶解液200.0 mL/L、番茄汁40.0 mL/L、NaCl 10.0 g/L,装液量50.0 mL、发酵温度32.14℃、发酵时间60.0 h。拟合实验模型结果显示:优化后发酵液对荧光假单孢的抑菌圈直径较优化前提高42%,对短小芽孢杆菌的抑菌圈直径较优化前提高47%。

In order to obtain safe and reliable new biological preservatives, Bacillus subtilis PNG27 fermented food was used to improve its antibacterial activity. Skim milk powder and tomato juice as well as incubation temperature and time were identified as key medium components and fermentation conditions by one-factor-at-a-time and Plackett- Burman experimental designs. A Box-Behnken response surface methodology was used to determine the optimal medium composition and fermentation conditions as 16.0 g/L wheat flour, 20.0 g/L skim milk powder, 200.0 mL/L soybean meal hydrolysate, 40.0 mL/L tomato juice, 10.0 g/L NaC1, 50.0 mL of medium in a 250-mL triangular flask, and incubation at 32.14 ℃ for 60.0 h. The maximum model-predicted diameter of the inhibition zone of the fermented broth under the optimized conditions was increased by 42% for Pseudomonasfluorescens and by 47% for Bacillus pumilus compared with those observed before the optimization.