骆驼刺源产乳酸的枯草芽孢杆菌分离鉴定和菌株特性研究

Isolation and identification of Bacillus subtilis producing lactic acid from Alhagi sparsifolia shap silage and the research on the characteristics of its strain

为了解疏叶骆驼刺青贮中乳酸菌的组成,用MRS培养基对骆驼刺青贮中的细菌进行分离和纯化,通过革兰氏染色、细胞形态学观察、生理生化试验和16SrDNA序列分析对分离的单菌落进行菌株特性研究和种属鉴定。结果表明：L14菌株呈杆状,G^＋,有芽孢;产乳酸,液化明胶,水解淀粉,触酶阳性,温度生长范围15-55℃,酸生长范围pH值为4-7,NaCl生长范围为2%-10%,可利用多种碳源和氮源;16SrDNA测序结果显示该菌株与ATCC6051的相似性为98.7%,说明该菌为枯草芽孢杆菌（Bacillussubtilis）。

To understand the composition of lactic acid bacteria on silage fermentation of Alhagi sparsifolia shap, MRS medium was used to separate and purify the bacteria. The isolated single colonies were used for the study of strain characteristics and species identification through Gram staining, cell morphological observation, physiological and biochemical tests and 16S rDNA sequencing. The results L14 strain was a rod - shaped and Gram - positive bacterium with spore ; it could produce lactic acid and could liquefy gelatin and hydrolyze starch, and it was catalase - positive. The temperature for bacterial growth ranged from 15℃ to 55 ℃, and the pH values for bacterial growth ranged from 4 to 7, and the NaCI ranges for bacterial growth ranged from 2% to 10%. The strain could utilize a variety of carbon and nitrogen sources, and it shared 98.7% similarity with the type strain ATCC 6051, which was analyzed by 16S rDNA sequencing. The result indicates that the strain is Bacillus subtilis.