Molecular Characterization of Lactobacilli Isolated from Piper betle L. var. Pachaikodi and Comparative Analysis of the Antimicrobial Effects of Isolate Lactobacillus plantarum KJB23 and Betel Leaves Extract

摘要

Traditionally Piper betle L. leaves have been used in India for fermenting certain foods. In our previous study, while fermenting Uttapam batter along with Piper betle L. var. Pachaikodi leaves led to suppression of gas formation and altered Lactic acid bacteria profile, especially in bacilli isolates compared to those observed in plain Uttapam batter fermentation. Hence, the aim of the present study was to understand the rationale behind these changes through characterization of Lactobacillus isolates from Piper betle L. var. Pachaikodi and also the leaves extracts for antimicrobial activity. Out of 72 isolates obtained from the betel leaves, only 10 isolates were bacilli which were chosen for their molecular characterization and to elucidate their inhibitory effects against major food borne pathogens and gas-forming bacteria and to compare with the effect of betel leaves extract. Random amplified polymorphic DNA (RAPD)-PCR and phenotype analysis was used to differentiate the isolates at strain level, 16S rRNA gene sequence for phylogenetic analysis and species-specific multiplex PCR analysis for sub-species identification. All isolates were identified as Lactobacillus plantarum subsp. plantarum. All Lactobacillus isolates were indigenous to leaf as they were resistant to betel leaves extract and showed maximum activity against some LAB and non-LAB indicator strains except Lactobacillus plantarum MTCC 6160 which was resistant. Among them, KJB23, 36 and 47 were the most effective. Particularly, the isolate KJB23 and ethanolic betal leaf extract showed rivaling inhibitory activity against major food borne pathogens, while dissimilar activity against gas forming bacteria. This study revealed that either Piper betle L. leaf or Lactobacillus strains from the leaves can be valuable for food applications when added to fermented products.