Probiotic Potential and Molecular Characterization of Weissella cibaria Isolated from Sala Lauak, a Traditional Indonesian Fermented Food

Objective: Sala lauak, a traditional fermented fish snack from West Sumatra, Indonesia, is a potential source of probiotic LAB. Information regarding LAB associated with this product remains limited. The spontaneous fermentation of salted fish under high-salt conditions selectively favours stress-adapted microorganisms. It is therefore hypothesised that LAB from sala lauak possess probiotic-related traits, including tolerance to acidic and bile conditions and antimicrobial activity against pathogenic bacteria. This study aimed to isolate and characterise LAB from sala lauak and evaluate its probiotic potential.Materials and Methods: Three isolates (SLA, SLB, and SLC) were purified and characterised based on morphological, biochemical, physiological, and molecular analyses. Tolerance to acid and bile salts was evaluated to assess gastrointestinal stress resistance. Antimicrobial activity was determined using inhibition zone assays against Escherichia coli O157, Salmonella sp., Staphylococcus aureus ATCC 25923, and Listeria monocytogenes. Molecular identification was performed using 16S rRNA gene sequencing.Results: All isolates were gram-positive, catalase-negative, rod-shaped bacteria with homofermentative metabolism. Isolate SLC showed the best overall gastrointestinal tolerance, with survival rates of 65.84±10.60% at pH 3 and 74.91±1.72% in 0.3% bile salts, and the strongest antimicrobial activity, producing inhibition zones of 29.10±0.99 mm against E. coli O157, 21.80±0.95 mm against Salmonella sp., 22.81±0.84 mm against S. aureus ATCC 25923, and 26.58±0.94 mm against L. monocytogenes. Molecular analysis identified all isolates as Weissella cibaria.Conclusion: W. cibaria SLC exhibited strong acid–bile tolerance and broad antimicrobial activity, highlighting its potential as a natural biopreservative and functional starter culture from sala lauak.