Whole-genome sequencing coupled with functional and safety validation reveals the probiotic and antimicrobial potential of traditional curd-derived Lactiplantibacillus plantarum.

Growing interest in natural formulations for food and health applications has intensified research on probiotic lactic acid bacteria (LAB). In this study, a LAB strain designated MIC-3 was isolated from traditional curd and evaluated using phenotypic, safety, and whole-genome approaches. The isolate exhibited typical LAB characteristics, being Gram-positive and catalase-negative with broad carbohydrate fermentation ability. MIC-3 demonstrated moderate broad-spectrum antimicrobial activity, with inhibition zones up to 8.7 mm against selected pathogens. The strain was susceptible to clinically relevant antibiotics and displayed γ-hemolytic activity, confirming its safety profile. It maintained viability under acidic conditions and tolerated bile salt concentrations up to 0.8%. Adhesion-associated properties were significant, with 85% auto-aggregation, strong co-aggregation with pathogens, and high cell surface hydrophobicity. Whole-genome sequencing identified the strain as Lactiplantibacillus plantarum and revealed genes supporting probiotic functionality, including stress tolerance (atp operon, groEL/groES, dnaK, clp), bile resistance (bsh/cbh, ABC transporters), adhesion (srtA, slpA, eps clusters), and bacteriocin production (pln cluster). Genes involved in lactic acid production, carbohydrate uptake, and vitamin biosynthesis were also detected, while no virulence-associated genes were identified. Collectively, these findings confirm the probiotic and functional potential of L. plantarum MIC-3 for food and health applications.