产共轭亚油酸乳酸菌的筛选及体外特性评价

Screening and Evaluation of in Vitro Characterization of Lactic Acid Bacteria Strains with High Conjugated Linoleic Acid Production

从117株泡菜和婴儿粪便源中筛选高产共轭亚油酸(CLA)的乳酸菌,对其进行功能性和安全性评价。采用紫外分光光度法初筛得到27株CLA转化率大于8%的菌株,通过GC-Q-TOFMS验证其CLA异构体组成,最终获得8株CLA转化率在10%以上,同时发酵液中c9,t11-CLA、t10,c12-CLA异构体质量浓度高于20μg/mL乳酸菌。对这8株菌进行自凝集、疏水性、黏附性能、胃肠道耐受能力、抑菌活性、安全性等体外特性评价。结果表明,植物乳杆菌NCU001044、NCU006007整体表现优异,自凝集率皆大于60%,具有中度疏水能力,且黏附率分别为8.81%,9.10%。两株菌在pH 2.5酸性条件下存活率分别为95.68%,84.63%,在质量分数为0.3%的胆盐中存活率均高于65%。安全性方面,两株菌对青霉素、苄卡西林、四环素、红霉素中性敏感或敏感,无溶血活性。本研究筛选到具有高效生物转化有益CLA异构体能力的植物乳杆菌2株,这2株菌具有良好的胃肠道定植能力,以及酸、胆盐耐受力,对致病菌表现出较高的抑制作用,可进一步投入发酵产品及功能性微生态制剂的开发。

This study aims to isolate lactic acid bacteria with high-yield conjugated linoleic acid from Chinese paocai and baby feces,and then conduct functional and safety evaluations.27 strains with CLA conversion rate greater than 8%were initially screened by ultraviolet spectrophotometry,identifying and classifying its CLA isomer composition by GC-Q-TOFMS.8 lactic acid bacteria strains with more than 10%conversion rate of CLA and the mass concentrations of c9,t11-CLA,t10,c12-CLA isomers in the fermentation broth were higher than 20μg/mL were obtained.The 8 strains were further evaluated characteristics such as self-aggregation,hydrophobicity,adhesion performance,gastrointestinal tolerance,antibacterial activity,and safety.The results showed that Lactobacillus plantarum NCU001044 and NCU006007 performed well overall,with self-agglutination rate of more than 60%,moderate hydrophobicity,and the adhesion rates were 8.81%and 9.10%,respectively.Their survival rates were 95.68%and 84.63%at pH 2.5 acidic conditions,and survival rates were higher than 65%in 0.3%bile salts.In terms of safety,the two strains are neutrally sensitive or sensitive to penicillin,benzamicin,tetracycline,and erythromycin and had no hemolytic activity.In this study,two Lactobacillus plantarum stains were screened with high biotransformation ability of beneficial CLA isomers and great probiotics potential.They have good ability to colonize the gastrointestinal tract,as well as acid and bile salt tolerance,besides show high inhibitory effect on pathogenic bacteria,which could be further used in the development of fermentation products and functional probiotics.