共轭亚油酸高产菌株的分离与鉴定

Isolation and Identification of Conjugated Linoleic Acid-producing Lactobacillus Strains from Fermented Pickle Brines

摘要:

共轭亚油酸（CLA）因具有抗肿瘤、增强免疫力、抗动脉粥样硬化、减肥、抗氧化等功效，在医药与保健食品领域显示了巨大的应用潜力。目前获得CLA的主要途径是化学合成法，化学合成法产量高，但产物异构体众多，成分复杂，分离提纯困难，生物法因其反应条件温和，产物成分较单一，在食品医药领域展现出了良好前景。为筛选共轭亚油酸高产菌株，本文在有氧条件下，采用MRS培养基从泡菜环境中分离出16株产共轭亚油酸的菌株，其中PC-3菌株具有较高的CLA转化率，且能将亚油酸转化为具有生物活性的c9，t11-CLA和t10，c12-CLA。经形态学特征（扫描电子显微镜）分析、生理生化试验分析（API-50CHL）及16S rDNA序列分析及同源性分析，PC-3菌株被鉴定为植物乳杆菌（Lactobacillus plantarum PC-3），其16S rDNA基因序列长度为1460 bp，该序列GenBank的登陆号为JX270774.1。

Abstract:

Conjugated linoleic acid (CLA) has wide application potential in medicine, food, and health products, because of its anticancer, immune regulatory, anti-atherosclerosis, antiobesity, and antioxidant activities. Currently, commercial CLA is typically produced through alkali isomerisation using sunflower oil as raw material, generating a mixture of CLA with undesirable isomer by-products. Use of CLA for nutraceutical and medicinal purposes requires safe isomer-selective synthesis. Hence, CLA biosynthesis naturally attracted much attention because of its specificity and safety. The aim of the present study was to isolate and identify Lactobacillus strains from the fermented pickle brines, which can convert linoleic acid (LA) into CLA under aerobic conditions. Using serial dilutions and plate streaking in de Man Rogosa Sharpe (MRS) agar medium under aerobic conditions, 16 CLA-producing Lactobacillus strains were isolated, among which PC-3 exhibited the highest production of CLA. Based on analyses using SEM, API-50CHL, and 16S rRNA gene sequencing, PC-3 was identified as Lactobacillus plantarum. The 16S rDNA gene sequence（1460bp）was submitted to GenBank under the accession number JX270774.1.