Streptomycetes are considered as the most prolific microbes for screening of secondary metabolites like antibiotics for combating the situation of clinical infections. Presently, soil samples were collected from eight different locations of the rice field of West Godavari district, Andhra Pradesh. The collected soil sample (1 g) was taken and serial dilution was carried out to screen actinomycetes primarily over the different culture media like oatmeal agar, ISP1, and Starch Casein Agar and colonies appeared whitish-gray, greyish-white, and turmeric-yellow. For the antimicrobial activity these microbes were tested over the Gram-positive (Bacillus subtilis), Gram-negative bacterium (E. coli) and fungi Aspergilus niger. Positive results reported in bacterium and negative against fungi. Extraction of antibiotics was done in conical flask using Yeast Extract-Malt Extract broth and inoculated with screened overnight starter culture and put it for fermentation at 28 °C for 8 days in rotary shaker and after completion supernatant was collected by centrifugation and crude collected by vortexing with equal ethyl acetate. 16S rRNA sequencing was done to identify the potential microbes and reported as Streptomyces avermitilis strain ZRS13. Antimicrobial activity of crude extract were reported through cell wall damage observed via FESEM using FESEM and PI staining. Here the present study concludes that rice field of Tadepalligudem are an abundant source of Actinomycetes, Streptomyces avermitilis ZRS13 which is capable to inhibit Bacillus subtilis and E. coli but didn’t showed any antimicrobial activity against Aspergillus niger. Antimicrobial activity were purported by mechanism like damage of bacterial cell wall, confirmed by FESEM and PI staining. From this study it confirmed that Streptomyces avermitilis ZRS13 can be used as potent strain for developing new antibiotics
Streptomycetes, Antibiotics, Secondary Metabolites, FESEM
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