Abstract: 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 As1.184. 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 radical-scavenging activity was seen in the cell-free supernatant, 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.

Key words: antioxidant activity, antimicrobial, lactic acid bacteria, screening, identi?cation