Purification and characterization of mejucin, a new bacteriocin produced by Bacillus subtilis SN7

Bacteriocin produced by Bacillus subtilis SN7 was purified and characterized. This bacteriocin showed stability over a wide range of pH (3.0–9.0), heat, and solvent treatments. The bacteriocin was digested completely by protease and peptidases, but not by α-amylase or lipase. Bacteriocin showed strong antibacterial activities against Gram-positive bacteria, especially B. cereus, but not Gram-negative bacteria. The bacteriocin was purified using preparative-high performance liquid chromatography. Amino acid sequence of the purified bacteriocin was determined to be LGPQLNKGCATCSIGAACLVDGPIPDEIAG (MW 3400). The bacteriocin was confirmed as a novel bacteriocin through a homology search, deposited into NCBI protein blast (NO. PRJNA 309888), and designated as mejucin. Mejucin showed bactericidal effects on B. cereus, which led to irreversible alteration of the cellular membrane as well as leakage of intracellular constituents of B. cereus. These results suggest that mejucin has promising potential as a food preservative in the food industry.