10.22376/ijpbs.2019.10.1.p1-12 Volume 3 Issue 3 2012 (July - September) The process of development of reliable and eco-friendly metallic nanoparticles is an important step in the field of nanotechnology. To achieve this use of natural sources like biological systems becomes essential. In the present work, we have investigated extracellular biosynthesis of silver nanoparticles at two molar concentrations (10 lessThan sup greaterThan -3 lessThan /sup greaterThan and 10 lessThan sup greaterThan -4 lessThan /sup greaterThan ) of AgNO lessThan sub greaterThan 3 lessThan /sub greaterThan using lessThan i greaterThan Streptomyces rochei lessThan /i greaterThan isolated from the marine sediment samples of Kanyakumari Coast , Tamil Nadu , India. The silver nanoparticles were analyzed by UV-Visible spectroscopy. The antimicrobial activities of silver nanoparticles were screened against common human pathogen lessThan i greaterThan Pseudomonas aeruginosa, E.coli, Klebsiella pneumoniae, Enterobactor faecalis lessThan /i greaterThan and lessThan i greaterThan Staphylococcus aureus. lessThan /i greaterThan The results showed silver nanoparticles synthesized at 10 lessThan sup greaterThan -4 lessThan /sup greaterThan molar concentration of AgNO lessThan sub greaterThan 3 lessThan /sub greaterThan displayed a significant antibacterial activity against lessThan i greaterThan S. aureus lessThan /i greaterThan and lessThan i greaterThan P. aeruginosa. lessThan /i greaterThan This study gives an innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties to reach the pharmaceutical companies searching for new unconventional antibacterial agents. P.Selvakumar, S.Viveka, S.Prakash, S.Jasminebeaula And R.Uloganathan Antibacterial activity, Marine sediment, silver nanoparticles and Streptomyces rochei 188-197