Physico-chemical characteristics of vernamycin-A antibiotic biosynthesis by streptomyces SP-AZ-SH-29

Seventy-five actinomycete isolates were isolated from different soil samples collected from different localities in Egypt. One of the actinomycete culture AZ-SH-29 from three cultures was found to produce a wide spectrum antimicrobial agent. The actinomycete isolate AZ-SH-29 matches with Streptomyces ramulosus in the morphological, physiological, and biochemical characters. Thus, it was given the suggested name Streptomyces ramulosus-AZ-SH-29. The parameters controlling the biosynthetic process of the antimicrobial agent formation including; different pH values, different temperatures, different incubation period, and different carbon and nitrogen sources, were fully investigated. The active metabolite was extracted using ethyl acetate (1:1, v/v) at pH 7.0. The separation of the active ingredient and its purification were performed using column chromatography (CC) technique. The physico-chemical characteristics of the purified antimicrobial agent have been investigated. This analysis indicates a suggested imperical formula of C20H25N2O5. The minimum inhibition concentrations ‘‘MICs’’ of the purified antibiotic and antiviral test were also determined. The purified antimicrobial agent was suggestive of being belonging to Depsipeptide (Mikamycin) group (Vernamycin-A antibiotic) produced by Streptomyces ramulosus, AZ-SH-29.