Characterization of selected lactic acid bacteria from Tapay: a starter for maguindanao ethnic delicacy in Cotabato City, Philippines

This study isolated and characterized lactic acid bacteria (LAB) from Tapay , a traditional ethnic starter culture sourced from Dalumangcob, Sultan Kudarat, Maguindanao (BARMM), Philippines. Phenotypic characterization revealed that the isolates were Gram-positive, non-spore-forming cocci capable of thriving under diverse environmental stresses, including broad pH (5.0–9.0) and salinity (0–8% NaCl) thresholds, as well as mesophilic temperatures 25–45 °C. Biochemical profiling identified all isolates as homofermentative lactic acid producers. While extracellular α -amylase and nitrate reductase production were generally absent across most strains, isolate TLB2 uniquely exhibited both nitrate and nitrite reductase activities. Crucially, the cell-free supernatants of these isolates demonstrated robust antimicrobial efficacy, mediated by bioactive metabolites such as organic acids and bacteriocins, which effectively inhibited key foodborne pathogens: Escherichia coli Biotech 1634, Bacillus cereus Biotech 1509, Staphylococcus aureus ATCC 25923, and Pseudomonas aeruginosa Biotech 1335. Genotypic validation via 16S rRNA gene sequencing confirmed that isolates TLB2, TLB3, TLB4, and TLB6 shared an 85% sequence similarity with Pediococcus pentosaceus , consistent with the typical profile of an acid-tolerant, anaerobic, sugar-fermenting bacterium native to fermented matrices. Meanwhile, isolates TLB1 and TLB5 were classified at the Pediococcus genus level. These findings underscore the biopreservative potential of indigenous Tapay LAB as functional starter cultures for regional food optimization and safety.