一株乳酸明串珠菌的鉴定及抑菌培养基配方优化

为了开发利用乳酸菌及其代谢产物相关资源,本研究对实验室前期从内蒙古马奶酒中分离保藏的一株乳酸菌进行16S rRNA基因序列分析,确定该菌为乳酸明串珠菌(Leuconostoc lactis),并以此菌株为研究对象,以抑菌圈直径大小为指标,采用单因素实验、响应面分析法对该菌株的培养基配方进行优化。通过单因素实验后,确定蔗糖、蛋白胨分别为最适碳源与最适氮源,利用响应面法优化培养基得到的最佳培养基配方为:蔗糖24.84 g/L,蛋白胨12.72 g/L,无水CH₃COONa 3.95 g/L,K₂HPO₄ 2 g/L,牛肉粉5 g/L,吐温80 1 mL/L,C₆H₁₇N₃O₇ 2 g/L,MnSO₄ 0.05 g/L,MgSO₄ 0.2 g/L,蒸馏水1 L。经过优化后,抑菌圈直径达到了(23.40±1.28)mm,比初始抑菌圈直径提高了2.1倍,与预测值基本一致。

Identification of a Strain of Leuconostoc lactis and Optimization of Its Bacteriostatic Medium Formula

In order to utilize the resource of Lactobacillus and its metabolites,a Lactobacillus from self-made kumiss in inner Mongolia was identified by the 16S rRNA sequence analysis. The bacteria was identified as Leuconostoc lactis and this stain was studied as the research object. The diameter of the bacteriostatic circle was taken as the index,and single factor experiment and the response surface method were used to optimize the medium composition. Sucrose was identified as the optimal carbon and peptone was identified as the optimal nitrogen. The optimal formula of the culture medium were as follows(g/L):sucrose 24.84 g/L,peptone 12.72 g/L,CH₃COONa 3.95 g/L,K₂HPO₄ 2 g/L,beef powder 5 g/L,Tween 80 1 ml/L,C₆H₁₇N₃O₇ 2 g/L,MgSO₄ 0.2 g/L,MnSO₄ 0.05 g/L.Under the optimal conditions,the diameter of inhibition zone had reached 23.40±1.28 mm,and it had increased 2.1 times than before,which was consistent with the value predicted by the mathematical model.