Antibacterial activities of indigenous yeasts isolated from pomegranate peels (Punica granatum L.)

Pomegranate peels (PGPs) are known to have the potential as antibacterial not only from their nutrient content but also the microflora. The activities might be caused by the existence of indigenous yeast that can be utilized to inhibit the growth of pathogenic bacteria. This study aims to identify antibacterial and antioxidant activity of indigenous yeast isolated from PGP. The research was conducted by experimental methods and followed by descriptive analysis. The study was done by the isolation of indigenous yeast from PGPs, which was identified using the rRNA sequence analysis of internal transcribed spacer (ITS) region with the primers of ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) and then compared with Basic Local Alignment Search Tools (BLAST) algorithm toward the GenBank. Antibacterial activities of indigenous yeast were tested with agar plug diffusion and time kill test toward Escherichia coli and Staphylococcus aureus. The yeast identification obtained two isolates similar to Hanseniaspora uvarum CBS 314 and two isolates of Pichia kudriavzevii ATCC 6258 which have antibacterial activity against E. coli and S. aureus. P. kudriavzevii PGP D4 have best antimicrobial activities with a strong activity against E. coli (±9 mm) and medium activity against S. aureus (±3.1 mm).