干酪乳杆菌LC-15的增菌培养基设计及生长动力学研究

对1株具有降胆固醇作用的干酪乳杆菌(Lactobacillus casei)LC-15的增殖培养基进行了筛选和优化,同时对其在分批培养时的生长动力学进行了研究。所得增菌培养基配方为0.1mol/L pH6.8的Na2HPO4-柠檬酸配制经蛋白酶预水解的10%脱脂乳冻干粉,再添加0.5%的葡萄糖,1.5%的胰蛋白胨,0.3%酵母浸膏,在此培养基中的最大菌数可达8.8×109cfu/mL,分别比MRS及脱脂复原乳中提高了1.35倍和0.75倍。得到的干酪乳杆菌在优化培养基中分批培养的生长动力学模型为:N(t)=3.4088/(1+e3.3560-0.3254t)。

Optimization of Enrichment Medium and Determination of Fermentation Kinetic Parameter for Lactobacillus casei LC-15

Probiotic starter culture plays an important role in developing probiotic yoghurt or fermented dairy products.In this paper,the optimal enrichment medium and fermentation kinetic parameter of a cholesterol-reducing probiotic strain Lactobacillus casei LC-15 were studied.The recipes of optimal media included enzyme-hydrolyzed 10% RSM,0.5% glucose,1.5% peptone,0.3% yeast extract and 0.1 mol/L pH 6.8 Na2HPO4-citric acid.The maximum viable count reached 8.8×109 cfu/mL,which was 1.35 and 0.75 fold higher than in MRS and 10% RSM respectively.And the kinetic model of Lactobacillus casei LC-15 in batch fermentation growth was N(t)=3.4088/(1+ e3.3560-0.3254t).Relative error of this model value and the experiment result was in the range of 5%.