We are presenting here the synthesis of specific bioactive substances that have demonstrated inhibitory effects against pathogenic microorganisms from actinomycetes strains. Ninety-two Streptomyces strains were isolated from soil sample collected from Sharkia province, Egypt. All these isolates were screened for their antimicrobial activity against Gram positive and negative bacteria. Among these 92 Streptomyces samples, the broad-spectrum strain Streptomyces sp. Am 52 was isolated from soil cultivated with wheat in Abo-Hamad and selected for compound characterization and purification. The nucleotide sequence of the 16s RNA gene (1.5 Kb) of the most potent strain evidenced 98% similarity with Streptomyces pulveraceus. From the taxonomic features, the actinomycetes isolate Am 52 matches with Streptomyces pulveraceus in the morphological, physiological and biochemical characters. Thus, it was given the suggested name Streptomyces pulveraceus, (Am 52). 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 was performed using both thin layer chromatography (TLC) and column chromatography (CC) techniques. The physicochemical characteristics of the purified antibacterial substance have been investigated. The study indicates a suggested empirical formula of C43H74N2O14. The minimum inhibition concentrations "MICs" of the purified antimicrobial agent were also determined. The purified antimicrobial agent was suggestive of being belonging to 16-membered Macrolide group (Spiramycin antibiotic) produced by Streptomyces pulveraceus, Am 52.
