酸奶中保加利亚乳杆菌的分离和鉴定

利用MRS琼脂培养基对保加利亚乳杆菌进行分离，分别挑取可疑茵落进行革兰氏染色，对镜检结果为革兰氏阳性菌，且细菌形状为杆状的菌种进行糖发酵试验生物化学鉴定。结论：在MRS琼脂培养基上，菌落较大、透明、灰白色，镜检细菌形状为杆状，麦芽糖和七叶苷发酵试验均为阴性，乳糖发酵阳性的菌种，即为保加利亚乳杆菌。

The isolation and identification of L. Bulgaricus

In present,the mixture of L.Bulgaricus and S.Thermophilus is commonly e xploitated as start culture in the co urse of yogurt fermentation in this study,L .Bulgaricus is isolated by the use of MRS and Elliker agar culture medium r espectively.The suspicious colonies are treated wit h Gram staining,and Gram -positive,spherical and rod bacteria are ident ified biochemically.Maltose and esculoside are used for L.Bulgaricus carbohydrate fermenta tion .To draw conclusions,L.Bulgaricus owned properties of transparent,gray -white,coloni es in MRS agar medium,and rod shape under microscopic examination as well as negative re-sults of maltose andesculoside ferm entation.nevertheless.