一株藏绵羊源短小芽孢杆菌的分离鉴定及生物学特性研究

为获得来源于藏绵羊的益生菌菌株,对健康母藏绵羊新鲜粪便进行90 ℃水浴处理5 min以筛选具有抗逆性的芽孢杆菌,再综合形态学、生理生化特征及16S rDNA序列分析进行鉴定,通过抑菌试验、耐酸、耐胆盐试验及产水解酶试验等方法对其生物学特性进行研究。结果显示,从新鲜粪便样品中分离到的芽孢杆菌菌株SWUN-G43对大肠杆菌和沙门氏菌有明显的抑菌效果,通过分析鉴定其为短小芽孢杆菌,该菌株在pH 2.0的环境中存活率为50.43%,在0.3%胆盐环境中存活率为44.35%,可产生蛋白酶和纤维素酶,对12种常用的抗生素具有很高的敏感性。从试验结果可分析出该短小芽孢杆菌(SWUN-G43)有一定的抗逆性和潜在的益生能力,且该菌株不含耐药质粒,不会在动物肠道微生态系统中造成抗生素抗性的水平传递,具有作为微生态添加剂开发的潜力。

Study on the Isolation,Identification and Biological Characteristics of a Strain of Bacillus pumilus Isolated from Tibetan Sheep

In order to select probiotic strains with probiotic potential isolated from Tibetan sheep,fresh excreta of the healthy female Tibetan sheep was processed with 90 ℃ water-curing treatment for 5 min,and Bacillus with resistance were screened.The morphological,physiological and biochemical characteristics and 16S rDNA sequence of the Bacillus were comprehensively analyzed and identified.Biochemical characteristics were studied by using antimicrobial test,acid resisting tests and bile salt resisting tests,hydrolytic enzyme test and other methods.The results showed that the Bacillus SWUN-G43 isolated from fresh excreta of Tibetan sheep had a significant antibacterial effect on E.coli and Salmonella.Through analysis and identification,the Bacillus SWUN-G43 was Bacillus pumilus.Its survival rate was 50.43% under the environment of pH 2.0 and 44.35% under the environment of 0.3% bile salt.It could produce protease and cellulase and was sensitive to 12 kinds of commonly used antibiotics.By studying,the Bacillus pumilus(SWUN-G43) had a certain degree of resistance and potential probiotic ability.Besides,the strain didn't contain R-plasmid and would not cause horizontal transmission of antibiotic resistance in the intestinal microecosystem.It also had the potential to be developed as a micro ecological additive.