Bacteriocin ZJQ2-1 produced by Pediococcus pentosaceus from traditional sweet wine koji: purification, characterization, and application in fermented glutinous rice

Background: Fermented glutinous rice has low alcohol content and abundant nutrients, and it is easy to be contaminated by Bacillus cereus during production and preservation. This study aimed to inhibit the spoilage bacterium Bacillus cereus in the fermented glutinous rice by bacteriocin-producing lactic acid bacteria and its bacteriocin. Results: Bacteriocin-producing Pediococcus pentosaceus JQ2-1 was isolated from traditional sweet wine koji and its bacteriocin ZJQ2-1 was purified by ethyl acetate extraction, cation exchange chromatography, gel chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC). Bacteriocin ZJQ2-1 was identified by HPLC-MS/MS, and the results showed it had a molecular weight of 1204.43 Da and the amino acid sequence was KIGLFGGAGVGKT. Further characterization analysis showed that the bacteriocin ZJQ2-1 was thermostable (30 min, 121°C), highly pH stable (2-10), sensitive to protease and exhibited broad-spectrum antibacterial ability against Gram-positive and Gram-negative bacteria. The count of Bacillus cereus in the fermented glutinous rice that was inoculated with P. pentosaceus JQ2-1 and bacteriocin ZJQ2-1 decreased by about 80% and 64% of that in the initial stage, respectively. Conclusions: These results indicated the potential of P. pentosaceus JQ2-1 and bacteriocin ZJQ2-1 as a bio-preservative in glutinous rice products.