Antimicrobial and Antioxidant Potential of Streptomyces sp. RAMPP- 065 isolated from Kudremukh soil, Karnataka, India

Abstract

Actinomycetes are among the industrially and therapeutically relevant microorganisms and are known to produce useful products such as antibiotics, enzymes, vitamins etc.  Among actinomycetes, genus  Streptomyces is known to produce a great array of products. In the present study, we have recovered a Streptomyces species RAMPP-065 from Western ghats soil of Kudremukh, Karnataka, India and determined its  antimicrobial and antioxidant activity. The isolate was recovered on Starch  casein agar and identified as Streptomyces species on the basis of  cultural, microscopic, staining and biochemical characteristics. Fermentation was carried out in Starch casein broth for 7 days and filtered. The culture filtrate was extracted with ethyl acetate and the solvent was evaporated to get the extract. Antimicrobial activity of extract was tested against 8 bacteria and 2 fungi by agar well diffusion method. Gram positive bacteria were more sensitive to extract than Gram negative bacteria. Among fungi, susceptibility to extract was higher in Candida albicans than Cryptococcus neoformans. The extract showed a dose dependent scavenging of DPPH free radical as revealed by bleaching of DPPH radical color with increase in concentration of extract. In ferric reducing assay, the absorbance was  found to increase with increase in extract concentration. Total phenolic content of extract, as estimated by Folin-Ciocalteau method, was 59mg Gallic acid equivalents/gram. The scavenging and reducing activity of extract were lesser when compared to reference compounds. The soils of Western ghats are rich sources for microorganisms with potent biological activities. To the best of our knowledge, this is the first report on  bioactivity of Streptomyces species from Kudremukh soil. Further studies
are to be carried out to characterize the Streptomyces isolate and the active principles present in the extract.