Antifungal effect of a bacteriocin of Bacillus methylotrophicus BM47 and its potential application as a biopreservative in traditional Bulgarian yogurt

Abstract

Bacteriocins are biologically active compounds of proteinaceous nature synthesized by a large number of microorganisms, including members of bacterial genus Bacillus and lactic acid bacteria (LAB). The broad antimicrobial spectrum of bacteriocins against various spoilage and pathogenic microorganisms stimulated the research efforts for their investigation and potential application in different branches of food industry as natural preservatives. The promising antimicrobial activity of bacteriocins makes them suitable for application as biopreservatives and alternatives of chemical preservatives in dairy industry for production of fermented or non-fermented milk products. Therefore, the aim of the present study was to evaluate the antifungal effect of a bacteriocin isolated from Bacillus methylotrophicus strain BM47 and the possibilities for its application as a potential biopreservative of traditional Bulgarian yogurt. The results demonstrated that the addition of a purified bacteriocin in dose of 1 AU/mL of milk led to significant reduction of the fungal spores and mycelial growth of the indicator microorganism Penicillium sp. in the yogurt, without a change of its organoleptic properties, and biochemical and microbiological parameters during the 4-week period of storage.