羊肠道益生芽孢细菌的筛选及D-4-1菌株胃肠道耐受

为了筛选具有肠道益生特性的芽孢细菌,进一步开发益生菌资源,该研究采用肠道病原菌拮抗试验,从羊的肠道内容物中筛选对大肠杆菌具有显著拮抗作用的芽孢细菌。通过梯度稀释平板试验及发酵液拮抗活性,分离纯化出1株抑菌活性较强的菌株D-4-1,经测定抑菌圈直径在18.7 mm;通过16S rDNA鉴定和菌株系统发育树分析,并结合生理生化结果,鉴定D-4-1为短小芽孢杆菌(Bacillus pumilus)。经胆酸盐耐受和人工胃肠道环境试验,该菌株可耐受0.3%的胆酸盐浓度,在pH4的人工胃液和pH6的人工肠液中能很好的生存。结果表明,D-4-1菌株具有较强的益生特性,可作为功能益生菌进行开发利用。

Screening of the Probiotic Bacillus and Tolerance of D-4-1 Strain from Sheep Intestinal

The study aimed to screen Bacillus that has probiotics function from the intestine and further develop the probiotics resources.The antagonistic test plate coating method was used to screen Bacillus with significant antagonistic effect on Escherichia coli from the intestinal contents of sheep.The results showed that a strain(D-4-1),with strong antibacterial activity,was isolated and purified through the gradient dilution plate test and fermentation liquid antagonistic activity test.The diameter of the antibacterial ring was determined to be 18.7 mm and D-4-1 was identified as Bacillus popilus by 16SrDNA identification,phylogenetic analysis and physiological and biochemical results.Further analysis showed that D-4-1 strain could tolerate 0.3%chaolate concentration and survive in artificial gastric juice(pH 4)and artificial intestinal juice(pH 6).In summary,the strain(D-4-1)has strong prebiotic characteristics that could be used as functional probiotics.