利用结合态亚油酸转化生成共轭亚油酸的乳酸菌筛选  

Screening for lactic acid bacteria that convert conjugated linoleic acid from non-free linoleic acid

作　　者：华凌燕 梅永超 杨波[1] 赵建新[1] 陈卫[1] 陈海琴[1] HUA Lingyan;MEI Yongchao;YANG Bo;ZHAO Jianxin;CHEN Wei;CHEN Haiqin(School of Food Science and Technology,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学食品学院,江苏无锡214122

出　　处：《食品与发酵工业》2024年第20期27-34,41,共9页Food and Fermentation Industries

基　　金：国家自然科学基金(32072186)。

摘　　要：共轭亚油酸(conjugated linoleic acid, CLA)是亚油酸的几何和位置异构体,具有多种生理功能,前期研究集中于以游离亚油酸为底物转化生成CLA,为了利用自然界中大量以结合态形式存在的亚油酸,该文从22株乳酸菌中筛选出以结合态亚油酸为底物转化生成CLA的菌株,结果显示8株乳酸菌能高效利用结合态亚油酸转化生成CLA,其中转化率最高的为短双歧杆菌CCFM683,转化率高达96%。为进一步探究该菌株高效转化结合态亚油酸生成CLA的原因,利用基因序列比对在短双歧杆菌CCFM683全基因组中筛选出2个编码脂肪酶的候选基因Lipase A/B,在大肠杆菌(Escherichia coli BL21)中异源表达进行功能分析,结果表明Lipase B能特异性水解亚油酸单甘油酯,证实以亚油酸单甘油酯为底物时菌株先将亚油酸单甘油酯水解成游离亚油酸后转化生成CLA,这为进一步研究乳酸菌利用结合态亚油酸提供了参考。Conjugated linoleic acid(CLA)is a geometric and positional isomer of linoleic acid with diverse physiological functions.Previous research mainly used free linoleic acid as a substrate to produce CLA.To access the abundant non-free linoleic acid in nature,this study investigated 22 strains of lactic acid bacteria to identify those capable of producing CLA from non-free linoleic acid.Results showed that 8 strains of lactic acid bacteria efficiently produced CLA from non-free linoleic acid,with Bifidobacterium breve CCFM683 exhibiting the highest conversion rate at 96%.To elucidate this phenomenon,two candidate genes,Lipase A and B,were selected from the genome of Bifidobacterium breve CCFM683 through sequence comparison and expressed in Escherichia coli BL21 for functional analysis.Results showed that Lipase B specifically hydrolyzed linoleic acid monoglyceride,and the strain initially hydrolyzed the monoglyceride into free linoleic acid,which was subsequently converted into CLA when used as a substrate.This study provides a valuable reference for future research on the utilization of non-free linoleic acid by lactic acid bacteria.

关 键 词：结合态亚油酸 共轭亚油酸 乳酸菌 脂肪酶 生物转化 

分 类 号：TS2[轻工技术与工程—食品科学与工程]