Potential antimicrobial activity of the antagonistic Bacillus strains to Saccharomyces cerevisiae

Abstract

Members of the genus Bacillus are known to have several metabolites with biologically active property. Six Bacillus species; B. Subtilis NS4182-01, B. subtilis NS4182-06, B. amyloliquefaciens NS4182-03, B. amyloliquefaciens NS4182-07, B. subtilis NS4182-04and G. stearothermophilus NS4182-05; were tested for their activity against Saccharomyces cerevisiae, pathogenic bacteria and fungi. The cell free supernatant, its chloroform extract as well as methanol extracts of its HCl precipitates showed inhibition activity towards S. cerevisiaeas well as antibacterial activity against the tested Gram positive and Gram negative bacteria with different inhibition zones diameters. The antagonism of whole Bacillus strains towards fungal species showed that the reduction percent of mycelial growth ranged from nil to as much as 51.4%, also chloroform and HCl extracts showed antifungal activity against tested fungi. The FT-IR analysis showed NH stretching vibration in protein, CH stretching vibration in aliphatic chain, C=O and NH bending vibration in amide I and amide II and the presence of lactone carbonyl group that typical for surfactin and fengycins families of lipopeptides. The fatty acids moiety of Bacillus extracts found to contain C14-C18 chain. It is to be concluded that finding lipopeptides producing Bacillus strains is of great importance from the industrial, pharmaceutical and biological control point of view.