响应面法优化枯草芽孢杆菌表面活性素的发酵工艺

为提高枯草芽孢杆菌FHYB201030的表面活性素生产能力，本文以枯草芽孢杆菌FHYB201030为试验菌株，CPC-BTB（氯化十六烷基吡啶-溴百里酚蓝）值为考核指标，利用单因素实验、Plackett-Burman试验、最陡爬坡试验和响应面试验进行优化，筛选出产表面活性素的最优发酵条件。Plackett-Burman试验筛选出对表面活性素产量影响显著的因素为温度、乳糖、谷氨酸（Glu），采用最陡爬坡设计和Box-Behnken中心组合设计三因素三水平试验，计算得到表面活性素产量最高的培养基成分为乳糖25 g/L、酪蛋白10 g/L、牛肉膏3 g/L、蛋白胨10 g/L、NaCl 5 g/L、Mn2+ 0.5 mmol/L、Glu 2.5 g/L；最佳培养条件为温度40 ℃、转速200 r/min、装液量30%（体积比）。在上述发酵条件下，枯草芽孢杆菌FHYB201030表面活性素的产量为0.48 mg/mL，较优化前的0.35 mg/mL提高34.56%。研究结果为提高表面活性素生产水平奠定良好的基础。

Optimization of Fermentation Conditions of Surfactin from Bacillus subtilis by Response Surface Methodology

In order to improve the surfactin production capacity of Bacillus subtilis FHYB201030, taking Bacillus subtilis FHYB201030 as the experimental strain, and CPC-BTB (cetylpyridyl chloride-bromothymol blue) value was used as the evaluation index. Single factor tests, Plackett-Burman test, steepest climbing test and response surface test were used to optimize the optimal fermentation conditions for surfactin production. Plackett-Burman test showed that temperature, lactose and glutamic acid (Glu) had significant effects on surfactin yield. The steepest climbing design and the Box-Behnken central combination design three-factor three-level test were used to calculate the culture medium composition with the highest surfactin yield: 25 g/L of lactose, 10 g/L of casein, 3 g/L of beef extract, 10 g/L of peptone, 5 g/L of NaCl, 0.5 mmol/L of Mn2+, 2.5 g/L of Glu. The optimum cultivation conditions were temperature of 40 ℃, rotation speed of 200 r/min, filling volume of 30%. Under the fermentation condition, the amount of surfactant produced by Bacillus subtilis FHYB201030 was 0.48 mg/mL, which was 34.56% higher than the 0.35 mg/mL before optimization. This result would lay a good foundation for improving the production level of surfactin.