乳酶生片中乳酸菌的分离鉴定及其增殖培养条件优化

该研究采用传统培养分离法从乳酶生片中分离乳酸菌，通过形态观察、生理生化试验及分子生物技术对其进行鉴定，并采用单因素及响应面试验对其增殖培养条件及培养基进行优化。结果表明，从乳酶生片中分离得到一株乳酸菌Y1，经鉴定为屎肠球菌（Enterococcus faecium），其最适培养条件为初始pH 8.0，生长温度37 ℃，接种量1%，最优增殖培养基为乳糖11 g/L，乳清粉10 g/L，酵母浸粉22 g/L，硫酸镁0.28 g/L，硫酸锰0.18 g/L。用此培养基培养所得E. faecium Y1的活菌数为2.90×109 CFU/mL，比优化前活菌数提高了80.12%。

Isolation,identification and enrichment culture condition optimization of lactic acid bacteria in lactasin tablet

In this study, lactic acid bacteria were isolated from lactasin tablet by traditional culture method, and were identified by morphological observation, physiological and biochemical tests, and molecular biotechnology. The culture condition and medium for its proliferation were optimized by single factor and response surface tests. The results showed that a strain of lactic acid bacterium Y1 was isolated and obtained from lactasin tablet and identified as Enterococcus faecium. The optimal enrichment culture conditions were initial pH 8.0, growth temperature 37 ℃, and inoculum 1%. The optimal medium was lactose 11 g/L, whey powder 10 g/L, yeast extract powder 22 g/L, magnesium sulfate 0.28 g/L, and manganese sulfate 0.18 g/L. The viable count of E. faecium Y1 cultured on this medium was 2.90×109 CFU/ml, which was 80.12% higher than that of before optimization.