一株产共轭亚油酸瘤胃细菌Streptococcus infantarius RB111的筛选与鉴定

Screening and identification of a Streptococcus infantarius RB111 that produces conjugated linoleic acid

从内蒙古鄂尔多斯山羊瘤胃中分离筛选到1株产共轭亚油酸的瘤胃细菌RB111,该菌株的cis9,trans11-CLA和trans10,cis12-CLA总产量为269.2 mg/L,其中cis9,trans11-CLA占52.64%,trans10,cis12-CLA占47.36%。对菌株RB111进行了形态学观察、生理生化鉴定、脂肪酸组成分析以及16S rRNA基因序列分析。16S rRNA基因序列分析结果表明该菌株与婴儿链球菌(Streptococcus infantarius)的模式菌株NCDO 599的序列相似性为99%,该菌株的形态特征及生理生化特性与文献报道的Streptococcus infantarius一致。脂肪酸组成分析结果显示,菌株RB111的细胞脂肪酸主要成分是C16:0、C18:1ω9c和C18:0,3种脂肪酸占脂肪酸总量的60.64%。综合以上结果,菌株RB111被鉴定为婴儿链球菌Streptococcus infantarius。

A bacterial strain producing conjugated linoleic acid was isolated from the goat rumen in Erdos,Inner Mongolia,the strain was designated as RB111.CLA production by the strain reached 269.2 mg/L,in which the percentage content of cis9,trans11-CLA accounted for 52.64% and that of trans10,cis12-CLA accounted for 47.36%.The strain RB111 was identified using its morphological characteristics,fatty acid composition and physiological and biochemical properties,as well as its 16S rRNA gene sequence.The strain RB111 shares 99% sequence identity with the type strain NCDO 599T of Streptococcus infantarius.The result of fatty acid composition analysis revealed that the major fatty acids present in the strain RB111 were C16：0,C18：1 ω9c and C18：0,the total account of the three kinds of fatty acids was 60.64%.The morphological characteristics and the results of physiological and biochemical properties of the strain were in well agreement with that of the type strain NCDO 599T of Streptococcus infantarius.On the basis of these data,the strain RB111 was definited to Streptococcus infantarius.