Mode of action of sakacin C2 against Escherichia coli

Sakacin C2 was a novel broad-spectrum bacteriocin produced by Lactobacillus sakei C2 isolated from traditional Chinese fermented cabbage. Sakacin C2 could inhibit not only Gram-positive bacteria but also Gram-negative bacteria. In this paper, the mode of action of sakacin C2 against Escherichia coli ATCC 25922, a typical Gram-negative bacterium, was determined. Addition of 360 AU ml−1 of sakacin C2 led to nearly entire inhibition of cell growth for at least 12 h, depolarization of trans-membrane electrical potential, efflux of UV-absorbing materials, fragmentary of cell membrane and permeabilization of cell to propidium iodide. These results suggested that the mode of sakacin C2 against E. coli ATCC 25922 was depolarization of trans-membrane electrical potential, pore formation in cell membrane and complete disintegration ultimately.