Purification, characterization, and mode of action of a novel bacteriocin BM173 from Lactobacillus crustorum MN047 and its effect on biofilm formation of Escherichia coli and Staphylococcus aureus

摘要

There is an increasing demand for dairy products,but the presence of food-spoilage bacteria seriouslyaffects the development of the dairy industry. Bacteriocinsare considered to be a potential antibacterialor antibiofilm agent that can be applied as a preservative.In this study, bacteriocin BM173 was successfullyexpressed in the Escherichia coli expression system andpurified by a 2-step method. Furthermore, it exhibiteda broad-spectrum antibacterial activity, high thermalstability (121°C, 20 min), and broad pH stability (pH3–11). Moreover, the minimum inhibitory concentrationvalues of BM173 against E. coli ATCC 25922 andStaphylococcus aureus ATCC 25923 were 14.8 μg/mLand 29.6 μg/mL, respectively. Growth and time-killcurves showed that BM173 exhibited antibacterial andbactericidal activity. The results of scanning electronmicroscopy and transmission electron microscopy demonstratedthat BM173 increased membrane permeability,facilitated pore formation, and even promoted celllysis. The disruption of cell membrane integrity wasfurther verified by propidium iodide uptake and lacticdehydrogenase release. In addition, BM173 exhibitedhigh efficiency in inhibiting biofilm formation. Therefore,BM173 has promising potential as a preservativeused in the dairy industry.