一株产脂肪酶芽胞杆菌菌株SJXYZ的鉴定

Identification of a Lipase-producing Bacillus sp. SJXYZ

[目的]对分离自市售高温灭菌牛奶的产脂肪酶菌株SJXYZ进行鉴定。[方法]通过16S rRNA基因序列及系统发育树分析、形态观察和生理生化特性分析,对菌株SJXYZ生物学特性进行初步鉴定。[结果]16S rRNA基因序列分析显示该菌株属于芽胞杆菌属(Bacillus),与B.altitudinis 41KF2b^T(高地芽胞杆菌)、B.xiamenensis HYC-10~T(厦门芽胞杆菌)、B.safensis FO-36b^T(沙福芽胞杆菌)、B.zhangzhouensis DW5-4~T(漳州芽胞杆菌)、B.australimaris NH7I_1~T(南海芽胞杆菌)和B.pumilus A^TCC 7061~T(短小芽胞杆菌)相似度皆为97%以上。系统发育分析显示,该菌株与B.altitudinis 41KF2b^T亲缘关系最近,但形成独立的进化分支,无法归入已知物种。菌株SJXYZ为革兰氏阳性,直杆状,运动性,最适温度为30~35℃,适宜p H为5~9,适宜盐度(Na Cl)为0%~5%;产脂肪酶,不产纤维素酶、淀粉酶、蛋白酶;对氨苄西林(10μg)、庆大霉素(10μg)、氟哌酸(10μg)、头孢唑啉(30μg)、四环素(30μg)、头孢噻吩(30μg)、链霉素(10μg)敏感。所测特性与B.altitudinis 41KF2b^T有较大的差异。[结论]菌株SJXYZ可能为新的物种,暂命名为Bacillus sp.SJXYZ。

[Objective]To identify strain SJXYZ,which was isolated from commercial sterilized milk.[Method]Strain SJXYZ was characterized by morphological,biochemical and physiological tests,16S rRNA gene sequence determination and phylogenetic analyses.[Result]16S rRNA gene analysis indicated that strain SJXYZ belonged to the genus Bacillus and had small higher than 97%similarity to B.altitudinis 41KF2b T,B.xiamenensis HYC-10 T,B.safensis FO-36b T,B.zhangzhouensis DW5-4 T,B.australimaris NH7I_1 T and B.pumilus ATCC 7061 T.The phylogenetic analysis showed that strain SJXYZ was closest to B.altitudinis 41KF2b T,but formed an independent branch separated from all the reference strains.Cells were gram-stain-positive,straight rod,motile.Growth occurred at pH 5-9,at 0%-5%NaCl,and with optimum temperature at 30-35℃.Lipase was passive.Proteinase,cellulase and amylase were negative.Sensitive to ampicillin(10μg),gentamycin(10μg),norxacin(10μg),cefazolin(30μg),tetracycline(30μg),cephalothin(30μg)and streptomycin(10μg).Genomic and phenotypic data of strain SJXYZ shew a big difference from B.altitudinis 41KF2b T.[Conclusion]On the basis of these findings,we propose that strain SJXYZ represents a new species of Bacillus for which we propose the name Bacillus sp.SJXYZ.