Purification and characterization of a novel bacteriocin from Lactiplantibacillus paraplantarum GS47

This study introduces a novel bacteriocin paraplantaricin GS6 produced by Lactiplantibacillus paraplantarum GS47 from pickles. Paraplantaricin GS6 was purified using ethyl acetate extraction, cation exchange chromatography and RP-HPLC. Mass spectrometry analysis determined the molecular weight of paraplantaricin GS6 as 1198.4 Da and its amino acid sequence as AVFPSLVRGPR. Paraplantaricin GS6 exhibited antimicrobial activity against both Gram-negative and Gram-positive bacteria. The MIC of paraplantaricin GS6 for Micrococcus luteus 10209 and Escherichia coli O157: HA was 31.25 μg/mL and 62.5 μg/mL, respectively. Paraplantaricin GS6 was considerably thermo-stable with 79.6% residual antimicrobial activity after exposure to 121 °C for 15 min. Paraplantaricin GS6 remained stable over pH 2-9 and was inactivated by proteases. Electron microscopy and fluorescence leakage analyses indicated that paraplantaricin GS6 disrupts cell membrane integrity of Micrococcus luteus 10209, leading to cell content leakage and subsequent death. Paraplantaricin GS6 inhibited or eliminated Staphylococcus aureus ATCC 25923, Listeria monocytogenes LM1, and Escherichia coli O157: HA in milk. These results revealed the potential of paraplantaricin GS6 as a biopreservative in food processing. • A new bacteriocin producing Lactiplantibacillus paraplantarum was identified • A novel bacteriocin paraplantaricin GS6 was purified and characterized • Paraplantaricin GS6 displayed antimicrobial activity and high stability • Paraplantaricin GS6 damaged cell membrane integrity of M. luteus • Paraplantaricin GS6 was able to kill pathogenic bacteria in milk