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 strain RB111 that produces conjugated linoleic acid

摘要:

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、C18:1 ω9c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。

关键词:共轭亚油酸;瘤胃细菌;婴儿链球菌;气相色谱

Abstract:

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 599^T 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 599^T of Streptococcus infantarius. On the basis of these data, the strain RB111 was definited to Streptococcus infantarius.

Key words:Conjugated linoleic acid;Ruman bacteria;Streptococcus infantarius;Gas chromatography