Characterization of a Bacteriocin Produced by Lactobacillus plantarum Lp6SH Isolated from “Sha’a”, a Maize-Based Traditionally Fermented Beverage from Cameroon

Abstract

Lactobacillus plantarum Lp6SH isolated from "Sha'a" a maize-based traditionally fermented beverage from Cameroon, produces a bacteriocin active against Gram-positive and Gram-negative bacteria including Listeria innocua, Staphylococcus aureus, Salmonella typhi, Bacillus cereus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and Shigella flexneri. Highest bacteriocin production in buffered MRS broth medium was achieved after 6 h of incubation without agitation. The bacteriocin is of proteinaceous nature as judged by the complete loss of activity after treatment by proteolytic enzymes. Interestingly, this bacteriocin was stable at 121 degrees C for 30 min, over a wide range of pH (2.0-10.0), and when treated with surfactants, organic solvents, EDTA and NaCl. The activity remained after 8 months of storage at 4 degrees C and the mode of action against Salmonella typhi ATCC 6539 was bactericidal. The bacteriocin was partially purified using ammonium sulphate precipitation, gel filtration and cation exchange chromatographies. Mass Spectrometry Analysis showed that the Molecular weight of the bacteriocin is 2.340 kDa.