瑞士乳杆菌MB2-1胞外多糖发酵条件优化

Optimization of Fermentation Conditions for the Production of Exopolysaccharides by Lactobacillus helveticus MB2-1

对1株分离自新疆赛里木酸奶中的瑞士乳杆菌(Lactobacillus helveticus MB2-1)胞外多糖(exopolysaccharide,EPS)的发酵条件进行优化。利用单因素试验确定发酵温度、乳糖添加量、氮源种类及添加量、无机盐种类及添加量对其EPS产量的影响。采用Box-Behnken法对其中的三因素三水平进行响应面分析以确定其最优工艺条件。结果表明:L.helveticus MB2-1 EPS提取的最佳条件为发酵温度37℃、Mg2+添加量为质量浓度0.2 g/100 mL、大豆蛋白胨添加量为质量浓度2 g/100 mL,在此工艺条件下,L.helveticus MB2-1 EPS的产量达到801.2 mg/L。

The fermentation conditions for the production of exopolysaccharides （EPS） by Lactobacillus helveticus MB2-1 isolated from Sayram traditional yogurt in Xinjiang were optimized.The effects of culture temperature,lactose concentration,nitrogen source and concentration,and mineral source and concentration on EPS yield were studied through single factor analysis.Response surface analysis （RSM） involving three independent variables at three different levels was carried out to determine the optimal process conditions by using Box-Behnken method.Results showed that the optimum extraction conditions were 37 ℃,0.2 g/100 mL and 2 g/100 mL for culture temperature,Mg2＋ concentration and soybean peptone concentration,respectively.Under these conditions,the yield of EPS by L.helveticus MB2-1 was as high as 801.2 mg/L.