<![CDATA[Background: Red cabbage sauerkraut (Brassica oleracea L.) is a fermented vegetable matrix that supports the growth of lactic acid bacteria (LAB), some of which produce bacteriocins with potential as natural food biopreservatives. Objective: This study aimed to isolate and phenotypically characterize LAB from red cabbage sauerkraut and evaluate the antibacterial activity and physicochemical stability of the partially purified bacteriocin against Staphylococcus aureus and Escherichia coli. Methods: LAB were isolated on MRS agar, characterized by colony and cell morphology, Gram staining, catalase activity, and motility, and screened for antibacterial activity. Bacteriocin from the selected isolate was partially purified by ammonium sulfate precipitation and dialysis. Stability was evaluated across pH 2–11, temperatures of 30–121 °C, pepsin exposure, Tween 20 and Tween 80, and UV-C irradiation. Antibacterial activity was assessed by agar diffusion. Results: Three presumptive LAB isolates (BAL1, BAL2, and BAL3) were obtained, with BAL1 showing the greatest antibacterial activity. Untreated bacteriocin produced inhibition zones of 11.2 mm against S. aureus and 12.8 mm against E. coli. Activity was retained most strongly at pH 3–5 and 30–40 °C, decreased after pepsin and UV-C exposure, and increased in the presence of Tween 20 or Tween 80. Conclusion: BAL1 from red cabbage sauerkraut produces a proteinaceous antibacterial substance with stability under acidic and moderate-temperature conditions, supporting its further characterization as a candidate food biopreservative.]]>
