产共轭亚油酸植物乳杆菌的筛选、鉴定与诱变

从传统泡菜中筛选得到1 株乳酸菌lp15 能够合成共轭亚油酸(CLA)，经16S rRNA 全序列分析法和API 系统鉴定法鉴定为植物乳杆菌(Lactobacillus plantarum)。利用人工诱变方法，以lp15 为出发菌株，采用紫外线、硫酸二乙酯(DES)依次诱变处理，经进一步液体发酵复筛获得多株突变菌株，CLA合成能力较出发菌株提高了29.3%～52.2%。其中lp15-2-1 突变菌株为CLA 生成能力最高菌株，MRS 培养液中添加0.2mg/mL LA 培养48h，CLA 产量达30.13μg/mL。经气相色谱(GC)检测分析，产物中cis9, trans11- 共轭亚油酸(c9, t11-CLA)占76.5%，trans10, cis12-共轭亚油酸(t10,c12-CLA)占23.5%。

Screening,Identification and Breeding of Conjugated Linoleic Acid-producing Lactobacillus plantarum by Mutation

A lactic acid bacterial strain, lp15, having the ability to synthesize conjugated linoleic acid (CLA) was isolated from pickle juice samples. The strain lp15 was identified as Lactobacillus plantarum based on full-length 16S rRNA sequence analysis and API system. This strain was treated by ultraviolet and DES to obtain several mutant strains, which exhibited 29.3%－52.2% enhancement for CLA production. The strain lp15-2-1 exhibited the highest CLA productivity, which was up to 30.13 μg/mL after 48 h culture in the MRS medium added with LA at 0.2 mg/mL level. According to gas chromatographic analysis, cis9, trans11-CLA was the predominant compound in the fermentation product, with a relative content of up to 76.5%. trans10, cis12-CLA approximately accounted for 23.5% of the fermentation product.