Isolation and Characterisation of a Soil Microbial Streptomyces Strain that Produces Membrane-Active Antimicrobial Metabolites

Abstract

In continuation of our previous research, more than 60 microbial strains that were isolated from soil samples collected from desert, farming and mineral regions of Iran and sixteen isolated strains that produced antimicrobial metabolites were found to be effective against Escherichia coli, Candida albicans and Saccharomyces cerevisiae and Staphylococcus aureus microorganisms. A total of 3 out of 16 strains produced membrane-active ethyl acetate fractions based on artificial vesicle assay. The antimicrobial and membrane interfering activities of crude extract and fractions from Actinomycetes strain were investigated in the current study. We report the isolation two compounds from biologically active fractions obtained from Streptomyces sp 0811 culture. Fractionation of Streptomyces sp 0811 demonstrated antimicrobial activities against bacteria and yeast strains. Vesicle assay showed membrane activity for the mentioned fraction. This suggests the presence of an antimicrobial membrane active agent. Further fractionation and purification strategies were applied to finally identify the isolated moleculesby using appropriate spectroscopic methods, such as 1HNMR, COSY, and LC-MS. The two identified structures are described to be indole-type and ether amino derivative.