MOLECULAR CHARACTERIZATION OF SECONDARY METABOLITE PRODUCING STREPTOMYCES SPECIES

Actinomycetes are most prolific source of antibiotics.  Present study was carried out to isolate Actinomycetes of antagonistic nature. In the present study soil samples were collected from different areas of Western Rajasthan. 10 isolates of Actinomycetes were isolated on Actinomycetes Isolation Agar (AIA). Several biochemical and physiological tests were performed for identification of these isolates. These Streptomyces isolates were screened for antagonistic potentiality against gram-positive and gram negative clinical isolates of human pathogenic bacteria. Isolates were cultivated in fermentation media for 7 days to extract out secondary metabolites or antibiotics of antimicrobial nature. Solvent extraction method was used to purifying antimicrobial compounds from filtrate. Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia, Salmonella typhi and Pseudomonas aeruginosa were used as test pathogen. Only isolate no. 3 and 4 was found to be effective against most of the pathogens.  Maximum activity of isolate no. 3 was recorded against Klebsiella pneumonia , minimum activity against Salmonella typhi and no activity was recorded against Pseudomonas aeruginosa. Whereas isolate no. 4 showed maximum activity against Staphylococcus aureus and minimum against Salmonella typhi and chloramphenicol was used as positive control. 16S rRNA sequencing of isolate no.3 and 4 had been done and isolate no. 3 shows 99% similarity with Streptomyces thermoliliacinus and isolate no. 4 shows 100% similarity with Streptomyces werrensis. Sequences obtained from 16S rRNA sequencing were submitted in NCBI data base. From all the results we concluded that Streptomyces isolates showed significant antagonism against test pathogens and reported first time from Western Rajasthan. Key words -   Streptomyces , antagonism, fermentation process.