一株耐热芽孢菌的鉴定及性质研究

Identification and physiological characteristics of a heat-resistant spore strain

在原奶中分离到一株耐热芽孢菌DZCP20140701CH,对其菌落状态进行观察,同时分析其最适生长温度、pH值以及芽孢耐热性,最后应用VITEK 2全自动微生物鉴定仪、核糖体RNA基因指纹技术和16Sr RNA测序技术进行鉴定。结果表明,该芽孢菌落为圆形、表面平坦有光泽,边缘整齐,半透明,革兰氏阳性芽孢杆菌。最适生长温度为37℃,pH值为7.5左右,其芽孢具有较强的耐热性,在100℃水浴加热60 min,芽孢存活率达到53.66%,121℃高压灭菌10 min存活率也有1.11%,直到121℃高压灭菌20 min才全部杀灭。3种鉴定方法结果显示,菌株DZCP20140701CH为Bacillus sporothermodurans。

A heat-resistant bacillus strain DZCP20140701CH was isolated from raw milk, This strain was observed by colonial morphology, its optimal growth temperature, pH value and heat resistance of the spores, Isolate was identified by VITEK 2 Compact system, Rdbotyping and 16S rRNA sequence analysis; The results shows that the spore colony is Gram positive bacillus with round, fiat surface, regular edge, glossy, and semitransparent colony. Its optimal growth temperature is 37 ℃, and optimal pH value is 7.5. Its spores has fairly strong heat-resis- tant character, which make its survival rate up to 53.66% heated for 60 min in boiling water at 100℃ , and up to 1.11% heated for 10 min in 121℃ autoclaved sterilization. It cannot be killed totally until 20 rain in 121 ℃ autoclaved sterilization. Three identification methods reveal that the stain DZCP20140701CH is Bacillus sporothermodurans.