干酪乳杆菌KLDS1.0381高密度培养条件研究

High-density culture conditions of Lactobacillus casei KLDS1.0381

以麦芽汁培养基为基础培养基,研究干酪乳杆菌生长的碳源、氮源、营养因子及培养条件,通过单因子试验和正交试验确定干酪乳杆菌的最优培养基配方和最佳培养条件,进一步选择菌种的最佳浓缩、富集条件。结果表明,培养基最优配方为麦芽汁培养基中添加1%乳糖、2%胰蛋白胨、20%西红柿汁和0.2%牛肉膏,初始pH 7.0;最适摇瓶装液量为100%。在最适条件下,37℃培养12 h后菌液中活菌数可达到1.37×1010cfu.mL-1。优化浓缩离心富集条件,4℃条件下,4 000 r.min-1离心30 min,离心后菌种存活率为76.27%,浓缩倍数为62.87,干酪乳杆菌高密度培养物中活菌密度可达8.62×1011cfu.g-1。

In this study, malt extract medium （MA） was selected as the basic medium, the carbon sauce, nitrogen source and growth factor of the culture medium was further optimized. The formula of the culture medium, cultivation conditions and the centrifuge-enrichment parameters of the Lactobacillus casei were optimized by means of single factor and the orthogonal experiments. The results showed that the formula of the culture medium consists of 1% lactose, 2% tryptone, 20% juice of tomato, 0.2% beef extract, using MA as the basic medium, with a initial pH 7.0. Under this optimal conditions, the maximum viable counts of the strain reached 1.37×10^11cfu·mL-1 after 12 h cultivation at 37 ℃. The concentration of the culture could be obtained at a speed 4 000 r. min1 of centrifugalization for 30 min, with the maximum starter survival rate of 76.27 %, and there were 62.87-fold of enrichment. The finally viable count was 8.62×10^11cfu·g-1