产亚油酸异构酶的乳酸菌的筛选

Screening of the lactobacillus producing linoleic acid isomerase

对16株乳酸菌产亚油酸异构酶(linoleate isomerase)的能力进行分析,紫外分光光度法和气相色谱法分析发酵液中的共轭亚油酸(CLA),筛选出产亚油酸异构酶的乳酸菌,PCR扩增筛选出菌株的亚油酸异构酶基因,并对其进行序列分析。结果显示,通过紫外分光光度法检测16株乳酸菌中有9株菌可将亚油酸(LA)转化为共轭亚油酸(CLA);气相检测6株乳酸菌的发酵液中存在cis-9,trans-11CLA和trans-10,cis-12CLA两种同分异构体(各占CLA总产量的50%);成功扩增出鼠李糖乳杆菌与亚油酸异构酶密切相关的肌球蛋白交叉反应抗原(MCRA)基因片段。

The ability of linoleic acid isomerase（LAI） formation by 16 Lactobacillus strains was studied.Conjugated linoleic acid（CLA）in fermentation broth from the 16 strains was determined by UV spectrophotometry and gas chromatography.The putative LAI genes from the strains were PCR amplified and sequenced.The results indicated that the CLA production of 9 Lactobacillus strains were determined by UV spectrophotometry.Fermentation broth of 6 Lactobacillus strains contained the cis-9, trans- 1 ! CLA （50% of total CLA） and trans-9, trans- 11 CLA （50% of total CLA）detected by gas chromatography. Myosin-cross-reactive antigen （MCRA）gene, which were closely associated with LAI ,were successfully amplified and sequenced from Lactobacillus rhamnosus（ATCC 9595）.