一株产酸凝结芽孢杆菌的筛选及耐受特性研究

从散养鸡肠道内容物分离到5株溶钙圈较大的芽孢菌，经高效液相色谱（HPLC）测定筛选到一株产酸性能较好的菌株DPLY-7，综合菌落形态、生理生化及特异性序列分析等手段，确定其分类归属，并对其耐受特性进行了研究。结果表明，菌株DPLY-7被鉴定为凝结芽孢杆菌（Bacillus coagulans）。在37 ℃培养10 h发酵液pH最低为5.04，其乳酸、乙酸含量分别可达2.60 mg/mL、1.24 mg/mL。菌株DPLY-7在pH值2.5环境中的存活率为79.76%，胆盐浓度0.5%环境中存活率为42.86%，可以耐受人工胃肠液及85 ℃水浴处理，是一株耐受性能优越的益生菌。

Screening and tolerance property of an acid-producing Bacillus coagulans

5 Bacillus strains with large calcium-dissolving circle were isolated from the intestinal contents of free-range chickens, and a strain DPLY-7 with good acid-producing ability was screened by HPLC. The classification and attribution of the strain were determined by means of colony morphology, physiological and biochemical characteristics and specific sequence analysis, and its tolerance property were also studied. The results showed that strain DPLY-7 was identified as Bacillus coagulans. The lowest pH of fermentation broth was 5.04 after incubation at 37 ℃ for 10 h. The contents of lactic acid, acetic acid reached 2.60 mg/ml and 1.24 mg/ml, respectively. The survival rate of strain DPLY-7 was 79.76% at pH 2.5 and 42.86% at bile salt concentration 0.5%, and it could tolerate artificial gastric and intestinal fluid and 85 ℃ water bath. Therefore, it was a probiotic with superior performance.