Production and characterization of bacteriocin from lactic acid bacteria isolated from fermented food products

Abstract

Bacteriocin is a natal antimicrobial which can be exploited to evade the inevitability of adding chemical preservatives to food products. This study is aimed at the production and characterization of bacteriocin from Lactic acid bacteria (LAB) isolated from fermented food products. Sixteen (16) samples of various fermented food products (abacha, fufu, ogi and yoghurt) were screened for the presence of bacteriocin producing LAB using agar well diffusion method. The strain designated C6 was selected for further studies due to its broad inhibitory effect on the growth of all tested organisms (Enterococcus faecalis ATCC 33090, Pseudomonas aeruginosa MN 515053, Listeria innocua ATCC 2127, Staphylococcus aureus, Escherichia coli, Candida spp and Aspergillus terrus MN907795). Molecular characterization spotted C₆ isolated from yoghurt as Lactobacillus fermentum (accession no. MN907811). Purification of the antimicrobial substance was achieved using High performance liquid chromatography (HPLC) with nisin as Standard which revealed it to be bacteriocin a proteinaceous antimicrobial that is stable to heat and organic solvents. Effect of substrate level on the growth of Lactobacillus fermentum and optimization of physicochemical parameters on bacteriocin production revealed optimum condition of 1.0 % glucose, 0.5 % sodium nitrate, pH of 6.0, incubation temperature of 35°C for 72h. This makes Lactobacillus fermentum and its bacteriocin a good antagonistic agent for exploitation in pharmaceutical and food processing industries as well as in the field of biotechnology.