Screening and Whole-Genome Analysis of a Sheep-Derived Lactic Acid Bacteria with Antibacterial Properties

Pediococcus pentosaceus is an important lactic acid bacterium widely utilised in fermented foods and animal probiotic preparations. However, strains derived from sheep remain relatively limited in systematic screening and genomic characterisation studies. This research isolated lactic acid bacteria from healthy Chahar sheep and screened strains with application potential through phenotypic evaluation, probiotic property analysis, and whole-genome sequencing. Results indicate that strain SSF2 exhibits rapid acid production capacity, strong bile salt tolerance, survival in simulated gastrointestinal environments, and significant antibacterial activity against major pathogens including Escherichia coli , Salmonella , Staphylococcus aureus , and Vibrio parahaemolyticus . SSF2 exhibits no haemolytic activity and maintains sensitivity to commonly used clinical antibiotics. Genome sequencing revealed SSF2 possesses a 1.85 Mb circular chromosome and two plasmids, encoding functional genes involved in carbohydrate metabolism, amino acid metabolism, stress tolerance, and potential bacteriocin biosynthesis. No virulence factors or antibiotic resistance genes were detected. Overall, both its phenotypic and genomic characteristics indicate that P. pentosaceus SSF2 is a safe and promising probiotic candidate strain with potential applications in ruminant feed additives and food biotechnology.