5株凝结芽孢杆菌的鉴定及抗逆性分析

Analysis of Stress Resistance and Identification of Five Bacillus Coagulans

通过细菌形态学、生理生化特征分析,5株鉴定均为凝结芽孢杆菌。以总菌数、抑菌性、热稳定性、耐人工胃肠液、耐胆盐能力等为评价指标,比较5个凝结芽孢杆菌产品的抗逆性。结果表明,5株凝结芽孢杆菌经65℃处理30 min后,存活率均超过100;A株抑菌性最好,对大肠杆菌和金黄色葡萄球菌抑菌率分别可达99.85和101.4,显著高于D株(P<0.01)和E株(P<0.01)。经过人工胃液和人工肠液处理后,菌株A和B在模拟胃液(pH 2.0)存活率较高,均在80以上,同时这A株菌完全耐受模拟肠液(pH 7.6);A株和B株耐受胆盐浓度可达1,其他三株的耐受胆盐浓度可达0.3。A株较其他株凝结芽孢杆菌具有较好的益生特性,在饲料生产上具有重要的应用价值。

To investigate the stress resistance of five Bacillus coagulans from different manufacturers,these strains were identified as Bacillus coagulans through the analysis of Bacterium morphology,physiological and biochemical characteristics.Stress resistance of five Bacillus coagulans were evaluated based on the total bacterial count,antibacterial activity,thermal stability,anti?artificial gastric juice and intestinal juice,bile tolerance.The results showed that the survival rate of 5 strains of Bacillus coagulans treated at 65℃for 30 min was more than 100%;the antibacterial rate of strain A was the best,which was 99.85%and 101.4%against Escherichia coli and Staphylococcus aureus respectively,which was significantly higher than that of strain D(P<0.01)and strain E(P<0.01).The results also showed that the survival rates of strains A And in simulated gastric juice(pH 2.0)were higher than 80%after treatment with artificial gastric juice and artificial intestinal juice.At the same time,this strain A is completely tolerant of simulated intestinal juice(pH 7.6).The strains A and B were completely tolerant to simulated intestinal juice.The bile salt concentration of strains A and B was 1%,and the bile salt concentration tolerance of the other three strains was 0.3%.Compared with other strains of Bacillus coagulans,strain A has better probiotic characteristics and has important application value in feed production.