Isolation and Characterization of Plant-Derived Lactic Acid Bacteria as Potential Probiotic

Plant lactic acid bacteria were isolated from plant-associated fermentative foods and crops, and their probiotic properties were investigated. Isolates K27 and O2 were isolated from Kimchi and onion, and identified as Lactobacillus plantarum on the basis of 16S rRNA gene analysis. The two strains were highly resistant to acid (an MRS broth at pH 2.5), where the survival rates of L. plantarum K27 and L. plantarum O2 were 90.2% and 97.3%, respectively. L. plantarum K27 and L. plantarum O2 also showed high bile resistance to 0.5% oxgall, with a more than 70% survival rate. They showed an inhibitory effect against pathogenic strains of Escherichia coli KCCM 40880 and Pseudomonas aeruginosa ATCC 10145. The antibacterial effect of the two strains was probably due to the presence of lactic acid. ACE inhibitory activities of the two strains ranged from 72.8% to 80.6% in MRS broth. Notably, the two strains showed high ACE inhibitory activity (89.2~98.2%) in MRS broth containing 10% skim milk. Antioxidant activity was tested by DPPH radical scavenging activity, with antioxidant activities of the strains being in the range of 56.8~61.5%. The results obtained in this study suggest that L. plantarum K27 and L. plantarum O2 may be potential probiotic starter cultures with applications with fermentative products.