食品科学2017，Vol.38Issue(10)：98-103,6.DOI:10.7506/spkx1002-6630-201710017
西藏牦牛奶渣中优势乳酸菌产胞外多糖及其耐受性
Exopolysaccharide (EPS)-Producing Ability and Tolerance of Dominant Lactic Acid Bacteria (LAB) Strains from Yak Milk Dreg in Tibet
摘要
Abstract
A total of 113 strains of lactic acid bacteria (LAB) were isolated from yak milk dreg in Tibet.Out of these,four dominant LAB stains were screened and compared for their exopolysaccharide (EPS)-producing ability,acid,bile and osmotic pressure tolerance,and antimicrobial activity.Results demonstrated that the EPS-producing abilities were different for the 4 selected strains,with strain GY-L003 producing the highest yield of EPS (379.94 mg/L).The LAB strains exhibited different levels of tolerance to three environmental factors and strains GY-L003 and GY-L004 could survive at extremely acidic pH of 1.5.At a bile concentration of higher than 0.4％,GY-L003 and GY-L004 could grow while GY-L055 and GY-Lll2 were inhibited.In terms of osmotic tolerance,GY-L003 and GY-L004 were superior,being able to grow when NaC1 concentration was up to 9％.All four LAB strains had strong antimierobial activity,among which GY-L004 had the strongest inhibitory effect against Staphylococcus aureus,with an inhibition zone diameter of (15.94 ± 0.31) mm,GY-L003 had the strongest inhibitory effect against both E.coli and Salmonella,with an inhibition zone circle of (18.21 ± 0.65) and (16.27 ± 0.50) mm,respectively,and GY-L112 exhibited the strongest inhibitory effect against Listeria monocytogenes with an inhibition zone diameter of (15.24 ± 0.35) mm.Taken collectively,our results suggested that both GY-L003 and GY-L004 had high EPS-producing ability,good tolerance to acid,bile and osmotic pressure,and strong antimicrobial activity.Accordingly,these strains have a good application potential and can provide a reference basis for application in the production of fermented dairy products.关键词
乳酸菌/胞外多糖/耐受特性/抑菌活性Key words
lactic acid bacteria/exopolysaccharide/tolerance/antimicrobial activity分类
轻工纺织引用本文复制引用
万金敏,杨丽娜,葛武鹏,张静,耿炜,李小鹏,吴小勇..西藏牦牛奶渣中优势乳酸菌产胞外多糖及其耐受性[J].食品科学,2017,38(10):98-103,6.基金项目
陕西省科技厅战略性新兴产业重大产品(群)项目(2015KTCQ03-08) （群）
