ABSTRACT:
Western Ghats of India are one of the thirty four biodiversity hot spots in the world. Biodiversity of Western Ghats has been richly explored in the form of flora and fauna but microbial forms have not been fully evaluated. Present study has been under taken to isolate and characterize Streptomyces species, a major antibiotic producing filamentous bacteria from Western Ghats soils of Karnataka, India. The isolates were characterized by their spore mass colour, aerial mycelium, texture, colony morphology, back ground colour, spore chain morphology and antibiotic production. Staining and biochemical characterisation tests were performed. The antibiotic property of the metabolites has been studied against 28 organisms including 16 pathogenic bacteria, 5 pathogenic yeasts and 7 filamentous fungi by well in agar method. The results from these studies revealed fascinating diversity of Streptomyces in the form of spore colour varying from white, gray, blue, red and pink. The colonies formed were discrete, lichenoid, leathery, powdery and butyrous colonies. The aerial and substrate mycelium varied in their colour of white, grey and blue series. The spore chain morphology studies revealed different arrangements of rectus, flexibilis, retinaculum aperatum – open loops, hooks and spira – simple spirals, short and compact spirals. The pigments were dark red, green, yellow, brown and brownish red in colour. The antibiotic spectrum of the isolates revealed activity to varied extents, the metabolites had antibacterial and antifungal activity. Results revealed that the metabolites are broad and narrow spectrum in activity. The zone of inhibition ranged from 0 to 40 mm. 50% of the metabolites inhibited both bacterial and fungal agents. 35% had broad spectrum antibacterial activity, 30% explicitly inhibited gram negative bacteria, 5% were specific for gram positive bacteria, 5% showed antifungal activity only and 5% were antiyeast in activity.