高产胞外多糖乳酸菌的筛选及培养条件优化

Screening for A Lactic Acid Bacteria with High EPS-producing Capacity and Optimization of Culture Conditions

从酸菜汁和生鲜奶中筛选出一株高产胞外多糖的乳酸菌L3,应用苯酚—硫酸法测定其胞外多糖的产量。分别改变基础培养基的碳源、氮源、发酵温度、时间、pH等条件,探索其对乳酸菌L3胞外多糖生物合成能力的影响。结果表明:葡萄糖和蛋白胨分别是乳酸菌产生多糖的良好碳源和氮源。该菌株胞外多糖的最佳生物合成条件为:初始pH值6.5,发酵温度37℃,发酵时间24h,此条件下胞外多糖的生物合成量为108.49mg·L-1。

A lactic acid bacteria（L3） with high EPS-producing capacity was screened from fermented Chinese cabbage and raw milk,its production of EPS was measured by Phenol-H2SO4 method.In order to study the effect of single factor on the EPS biosynthesis capacity,optimization of carbon and nitrogen source in medium and culture conditions such as temperature,time and pH for L3 were carried out in the paper.The results showed glucose and peptone was favorable carbon and nitrogen source for L3 to produce EPS.The optimal culture condition for producing EPS were：initial pH 6.5,fermented at 37℃ for 24h.The maximum biosynthesis amount of EPS was 108.49mg·L^-1.