Investigation of antimicrobial effects of lipid extracted fromStreptomyces alboflavus

Background and Aim : The aim of the present study was to investigate the antimicrobial activitiesof a Streptomyces strain that had previously been isolated from Tehran province soil samples.Methods : Methods: A Streptomyces strain was identified from Tehran province soil samples. Thestrain's genus was determined using phenotypic and biochemical analyses. Using MEGA۷software, a gene tree was designed to show the relationship between isolates by the neighborjoiningmethod based on the nucleotide difference number model. The presence of antimicrobialmetabolites was assessed in Streptomyces isolates using the Cross-Streak method. In flasks with۲۵۰ cc of BHI broth nutritional medium, the strains that exhibiting antimicrobial activities wascultivated after preliminary screening. Minimum Inhibitory Concentration (MIC) determinationwas performed by the microdilution method. Using concentrations established by themicrodilution method, the metabolite's antibacterial activities were exanimated in fresh rabbitserum. The isolated metabolite's stability was examined at ۶۰ °C and in the presence of proteinaseK (۵۰ mg/ml). In order to further purify the metabolite, precipitates of the metabolite were preparedand tested for the presence of organic substances. Finally, mass spectrometry and Highperformanceliquid chromatography (HPLC) were employed to investigate the metabolite'schemical structure and approximate formula.Results : Results: The isolate (S۹۲۱) and Streptomyces alboflavus had ۹۹ percent sequencesimilarity. S۹۲۱ strain exhibited broad-spectrum antibacterial activity against B. cereusATCC۱۱۷۷۸, Escherichia coli ATCC ۲۵۹۲۲, Pseudomonas aeruginosa ATCC ۲۷۸۵۳, Klebsiellapneumoniae ATCC ۷۰۰۶۰۳, Salmonella Typhimurium ATCC ۱۴۰۲۸ and Shigella sonnei RI۳۶۶.The antibacterial activity of metabolite was retained at ۶۰ ° C and in the presence of proteinase K,with no visible changes in the growth inhibition zone against the tested microorganisms. MassSpectra analysis of the supernatant from S۹۲۱ isolate showed that it was very similar toC۳۲H۳۲O۱۴.Conclusion : Conclusion: As a result of this study, it has been concluded that strain S۹۲۱ has abioactive metabolite, which has broad antibacterial activity against a wide range of humanpathogens.

کلیدواژه ها:

Streptomyces alboflavus ، antimicrobial activity ، Soil microbiology ، Bioactive metabolite