Isolation and Characterisation of Antagonistic Actinobacteria from Mangrove Soil

The aim of the present study was to isolate and screen actinobacteria having antagonistic activities against pathogenic microorganisms. A total of twenty actinobacteria strains were isolated from the mangrove sediment. Of these four active isolates were identified as Streptomyces species by means of morphological, physiological, biochemical and cultural characteristics. These isolates were subjected to shake flask fermentation and the secondary metabolites were extracted with ethyl acetate and screened for their antimicrobial activities against selected bacterial and fungal pathogens. The results showed that among the active isolates, four isolates (BC 01, BC 02, BC 03 and BC 04) showed promising activities against the selected test pathogens. These four extracted isolates were analyzed for UV Spectrophotometric and HPLC. Spectral data of the extracted compound revealed its antimicrobial nature. The UV spectrum of the methanol extracts for the active isolates showed absorbance peaks ranging between 207-223 nm. Two to three bioactive regions were detected on the HPLC. The results indicate that Streptomyces strains isolated from mangrove sediment produce potential antibacterial, antifungal and broad spectrum antibiotic compounds.