乳双歧杆菌U9高密度发酵培养基的优化研究

Optimization of Culture Medium of Bifidobacterium Animalis Subsp.Lactis U9 Strain

乳双歧杆菌U9是一株具有优良功能和产业化应用前景的益生菌。为了更好地实现该菌株产业化应用，对该菌株高密度发酵培养基进行了优化。以乳双歧杆菌U9的活菌浓度为评价指标，以改良MRS培养基（添加L-半胱氨酸）为基础培养基，利用正交试验，对增殖培养基中氨源、促生长因子以及无机盐的添加量进行了优化，确定最佳活菌浓度时的培养基配方为：蛋白胨75g／L，酵母粉100g／L，牛肉膏75g／L，西红柿汁30g/L，葡萄糖200g／L，无水乙酸钠50g／L，七水合硫酸镁0．6g／L，一水合硫酸锰01g／L，柠檬酸氢二铵2．0g／L，磷酸二氢钾20g／L，吐温-801．0g／L，L-半胱氨酸盐酸盐0．5g／L。对优化后的培养基进行50L发酵罐小试试验。试验结果表明，乳双歧杆菌U9在10h左右达到稳定期，菌体浓度可达4．2×10^9CFU／mL，与基础培养基培养结果（1．1×10^9CFU／mL）相比，菌体浓度显著提高，具有实际应用价值。

Bifidobacterium animalis subsp.Lactis U9 has the excellent function and the prospect of industrial application. The high density fermentation medium for Bifidobacterium animalis subsp.Lactis U9 was optimized. The additive amount of nitrogen source, growth stimulating factor and inorganic salt were optimized by orthogona test method using living Bifidobacterium animalis subsp. Lactis U9 concentration as evaluation index. The optimal culture medium formula was peptone 7.5 g/L, yeast extract powder 10.0 g/ L, beef extract 7.5 g/L, tomato juice 30 g/L, D-glucose 20.0 g/L, sodium acetate anhydrous 5.0 g/L, magnesium sulfate heptahydrate 0.6 g/L, manganese sulfate monohydrate 0.1 g/L, di-ammonium hydrogen citrate 2.0 g/L, di-potassium hydrogen phosphate trihydrate 2.0 g/L, Tween-80 1.0 g/L, L-cysteine hydrochloride 0.5 g/L. A 50 L fermenter small-scale test was done to examine the effect of optimized culture. The result showed that Bifidobacterium animalis subsp.Lactis U9 would reach the stationary phase after about 10 h, and the cell concentration was 4.2×10^9 CFU/mL, which showed the practical application value of Bifidobacterium animalls subsp.Lactis ug.