内蒙古锡林郭勒盟地区传统奶油制品中产共轭亚油酸乳酸菌的分离筛选与鉴定

本实验从内蒙古锡林郭勒盟地区传统奶油制品中分离筛选共轭亚油酸（conjugated linoleic acid，CLA）高产乳酸菌。采用紫外分光光度法检测菌株发酵液中CLA含量，筛选出高产菌株，分析其菌落特征、细胞形态及生理生化特性，并结合16S rDNA全序列分析以及系统发育树，鉴定其种属。结果表明，从样品中共筛出20 株产CLA菌株，当亚油酸（linoleic acid，LA）添加量为0.06%，接种量为2%时，分离自镶黄旗酸油的11 株产CLA菌株中，菌株HS4产量最高，为23.586 μg/mL，转化率为7.86%，经鉴定其为干酪乳杆菌（Lactobacillus casei）；分离自正镶蓝旗稀奶油的9 株产CLA菌株中，菌株LX5产量最高，为20.508 μg/mL，转化率为6.84%，经鉴定其为副干酪乳杆菌（Lactobacillus paracasei）。

Isolation,Screening and Identification of Lactic Acid Bacteria with Conjugated Linoleic Acid-Producing from Traditional Cream Products in Xilingol League of Inner Mongolia

The objective of this study was to isolate lactic acid bacteria (LAB) with high ability to produce conjugated
linoleic acid (CLA) from traditional cream products in Xilingol League of Inner Mongolia. CLA content in fermented
broth was determined by UV-spectrophotometry, and the strains with the highest CLA-producing ability were identified by
analyzing their colony characteristics, cell morphology, biochemical and physiological characteristics, and the phylogenetic
tree generated with MEGA 6 software based on 16S rDNA sequence. Twenty CLA-producing strains were isolated from
traditional cream products, 11 strains of which were present in samples collected from Xianghuang Banner and the remaining
9 strains were found in samples collected from Zhengxianglan Banner. HS4 with the highest CLA-producing capacity among
the strains isolated from cream samples collected from Xianghuang Banner was identified as Lactobacillus casei, producing
23.586 μg/mL CLA with a conversion efficiency of 7.86% when it was cultured at an inoculum size of 2% in the presence
of 0.06% linoleic acid; among the strains isolated from cream samples collected from Zhengxianglan Banner, LX5 with the
highest CLA-producing capacity was identified as Lactobacillus paracasei, producing 20.508 μg/mL CLA with a conversion
efficiency of 6.84% under the same culture conditions as described for HS4.