422CHARACTERIZATION AND ANTAGONISTIC ACTIVITY OF ACTINOMYCETES FROM COASTAL SOIL OF MAHABALIPURAMActinomycetes from different ecosystems have long been accepted as organism of antibiotic producers and organism of enzyme producers. In the present study, the actinomycetes isolates obtained from coastal soil of Mahabalipuram, Tamil Nadu, India were screened for their antibacterial activity by Kirby Bauer well diffusion method. In screening, four actinomycetes Mah2, Mah7, Mah25 and Mah26 were selected for further studies. Morphological, Biochemical and Physiological characteristics were studied to characterize the actinomycetes. The four isolates were mass cultured in ISP2 broth and the bioactive metabolites were isolated using centrifugation phase separation method by adding equal amount of eight different solvents. Bacterial strains such as Staphylococcus aureus, Micrococcus luteus, Bacillus cereus, Proteus mirabilis, Pseudomonas fluorescens, Proteus vulgaris, Neisseria mucosa, Enterococcus faecalis and Enterobacter cloacae were obtained from MTCC, Chandigarh, were challenged with the extracts by Kirby Bauer well diffusion method. Isolate Mah25 was selected as the most potent actinomycete among the four isolates and the solvent ethyl acetate extracted the bioactive compounds better than other solvents. Isolate Mah25 exhibited good antibacterial activity against Staphylococcus aureus, Micrococcus luteus, Enterococcus faecalis, Proteus vulgaris, Proteus mirabilis, Enterobacter cloacae and Neisseria mucosa. The potent isolate Mah25 was characterized by 16S rRNA sequencing and the isolate was identified as Streptomyces sp. MAH25 (AB899157)febina.623@gmail.comResearch522014Actinomycetes,Bacterial pathogens,Coastal area, Ethyl acetate extract,Streptomyces sp. MAH25Febina Bernice Sharon S,Rajakani Reeta,Rachel Regi DanielDepartment of Botany and Microbiology, Lady Doak College, Madurai-625002, Tamil Nadu, India.,Department of Botany and Microbiology, Lady Doak College, Madurai-625002, Tamil Nadu, India.,Department of Botany and Microbiology, Lady Doak College, Madurai-625002, Tamil Nadu, India.