A Report on Antimicrobial Activity of Actinomycete, Streptomyces S12c Species

The focus of this study was to isolate and to identify the actinomycetes having antimicrobial activity. A total of 145 actinomycetes were recovered from soil samples collected from different areas in Tamilnadu, India. All these isolates were screened for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeroginosa, Klebsiella pneumonia and Candida albicans. On primary screening for antimicrobial activities, out of 145 isolates of actinomycetes, only 22 isolates showed the activity against test organisms. On Secondary screening of 22 isolates, the strain S12c with good antimicrobial activity was selected for secondary metabolite fermentation. 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 column chromatography technique. The partially purified antibiotic was subjected to partial characterizations viz., thermal stability, pH stability, effect of detergents, effect of enzymes, and effect of ergosterol. The minimum inhibition concentrations “MICs” of the purified antibiotic were also determined. Thus the antibiotic produced by Streptomyces species S12c was found to exhibit potent activity against Staphylococcus aureus and Candida albicans. Various studies done and the results obtained in the present investigation indicated that Streptomyces species S12c produced an effective and stable antifungal and antibacterial antibiotic.