IDENTIFICATION AND BACTERIOCIN-PRODUCING POTENTIALS OF BACTERIAL SPECIES OBTAINED FROM LOCALLY FERMENTED PARKIA BIGLOBOSA

Fermentation of Parkia biglobosa (African locust bean) is a traditional West African practice producing culturally significant condiments like “iru,” which are naturally enriched with protein-hydrolyzing and flavor-developing microflora. This study isolated and identified bacteriocin-producing bacterial species from locally fermented P. biglobosa collected across local markets in Ikare-Akoko, Ondo State, Nigeria, and evaluated their antagonistic potential against Gram-positive and Gram-negative clinical targets. Nineteen (19) bacterial isolates were retrieved and identified via morphological and biochemical testing. The screening revealed a diverse ecosystem composed of beneficial fermenters (Bacillus subtilis, Bacillus licheniformis, Lactobacillus plantarum, and Enterococcus faecalis) alongside opportunistic Gram-negative taxa (Klebsiella pneumoniae and Pseudomonas aeruginosa). Agar well diffusion assays using cell-free supernatants (CFS) demonstrated isolate-dependent antibacterial actions. Most notably, Enterococcus faecalis (isolate JB2a) and Klebsiella pneumoniae (isolate JU3a.1) exhibited profound inhibitory activities against Pseudomonas aeruginosa, yielding zone clearances of 40 mm and 31 mm, respectively. Other isolates, including Bacillus sp. (JB3a), demonstrated strong antagonistic clearing (26 mm) against Escherichia coli. These findings confirm that traditional fermented condiments serve as valuable natural reservoirs for potent bio-preservative compounds capable of suppressing critical clinical pathogens.