10.22376/ijpbs.2019.10.1.p1-12 Volume 3 Issue 4 2012(October - December) Improvement of eco-friendly procedures for the nanoparticles synthesis is the growing in to the field of nanotechnology. In this report we used the extract of marine brown seaweed lessThan i greaterThan Turbinaria conoides lessThan /i greaterThan for the silver nanoparticles synthesis is the new one, cost effective and environmentally favorable. The surface plasmon resonance band positioned at 420 nm for silver nanoparticles was characterized by UV-Visible Spectrophotometer. X-Ray diffraction (XRD) data illustrated the crystalline nature of silver nanoparticles. Scanning electron microscope (SEM) shows the spherical shaped with the average size of 96 nm. The possible biomolecules are amines and poly phenols may responsible for reduction of silver ions was identified through Fourier transmittance infrared spectroscopy (FT-IR). Further these biosynthesized silver nanoparticles were found to be highly toxic against gram positive bacteria lessThan i greaterThan Bacillus subtilis lessThan /i greaterThan (MTCC3053) and gram negative bacteria lessThan i greaterThan Klebsiella planticola lessThan /i greaterThan (MTCC2277) was analyzed by zone of inhibition. SHANMUGAM RAJESHKUMAR, CHELLAPANDIAN KANNAN AND GURUSAMY ANNADURAI Turbinaria conoides, Silver nanoparticles, Scanning electron microscope, Antimicrobial activity 502-510