Purification and characterization of a novel bacteriocin from Lactiplantibacillus plantarum Z057, and its antibacterial and antibiofilm activities against Vibrio parahaemolyticus

Vibrio parahaemolyticus and its biofilm threaten food safety and human health. Bacteriocins are known to inhibit various foodborne bacteria and their biofilms; however, few bacteriocins with antibiofilm activity against V. parahaemolyticus have been reported. Herein, a novel plantaricin Z057 from Lactiplantibacillus plantarum Z057 was extracted with ethyl acetate, purified by Sephadex LH-20 gel chromatography and reversed-phase highperformance liquid chromatography, and identified by nano-liquid chromatography coupled with tandem mass spectrometry. Its molecular mass and amino acid composition were 1272.61 Da and A-G-G-D-G-G-H-G-G-S-I-I-LY, respectively. Plantaricin Z057 presented a broad antibacterial spectrum against Gram-positive and Gramnegative pathogens. Moreover, it also exhibited excellent heat tolerance, maintained antibacterial activity at pH 2.0-4.0, and was susceptible to common proteases (pepsin, trypsin, papain, proteinase K). In addition, scanning electron microscopy revealed that plantaricin Z057 destroyed membrane integrity and caused cell deformation and cytoplasmic leakage. The crystal violet staining and XTT reduction assays revealed that plantaricin Z057 markedly decreased biofilm biomass and metabolic activity of V. parahemolyticus. Fluorescence microscopy showed that plantaricin Z057 efficiently inactivated sessile cells, and damaged integrated biofilm structure by reducing the extracellular polymer content. In summary, plantaricin Z057 exhibited significant potential for controlling V. parahaemolyticus and could be used in food production as a biological preservative.