1株具抑菌和抗氧化活性乳酸菌的筛选及鉴定

摘要

In this study,lactic acid bacteria were isolated from pickle samples.All the isolates were primarily screened for their antimicrobial activity against six indicator strains such as Lactobacillus plantarum PL2 and Escherichia coli As 1.184.Then the scavenging activities against hydroxyl radicals,superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were measured to evaluate antioxidant activity of the isolates with antimicrobial activity.The results showed that eight strains with both antimicrobial and antioxidant activity were screened from pickles.The highest levels of antimicrobial activity and antioxidant activity were recorded in strain b-2,which was identified as L.plantarum by its physiological,biochemical and molecular characteristics.According to the results of antioxidant activity,the cell-free extract of b-2 showed the highest hydroxyl radical-scavenging activity,which scavenged 67.6％ hydroxyl radical,while the intact cells exhibited the highest superoxide anion-scavenging activity,which scavenge 62.8％ superoxide anion radical,and the highest DPPH radicalscavenging activity was seen in the cell-free supematant,which scavenged 91.3％ DPPH radical.To conclude,L.plantarum b-2 has good bacteriostatic ability and antioxidant capacity,and holds great potential as a functional lactic acid bacterial starter.%从市售酸泡菜中分离纯化乳酸菌,以植物乳杆菌PL2、大肠杆菌Asl.184等为指示菌筛选具有抑菌活性的乳酸菌;以对1,1-二苯基-2-苦基肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、·OH、O2-·清除率为指标,进一步筛选高抗氧化活性菌株.结果表明:从市售酸菜中分离筛选出8株兼具抑菌活性和抗氧化活性的乳酸菌菌株,其中菌株b-2的抑菌活性和抗氧化活性最强,根据生理、生化和分子生物学特征将其鉴定为植物乳杆菌.抗氧化活性测定结果显示,该菌株的无细胞提取物对·OH的清除率最高,为67.6％;其完整细胞对O2-·的清除活性最强,清除率为62.8％;其无细胞发酵上清液对DPPH自由基清除率高达91.3％.植物乳杆菌b-2具有较好的抑菌能力和抗氧化能力,作为功能性乳酸菌发酵剂,具有十分重要的开发潜力.