Extracellular biosynthesis of silver nanoparticles by the culture supernatant of Bacillus licheniformis

Development of reliable and eco-friendly processes for synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. One of the options to achieve this objective is to use 1 natural factories' such as biological systems. In this study, we report the synthesis of nanoparticles of silver by reduction of aqueous Ag+ ions with the culture supernatant of Bacillus licheniformis. The morphology of the nanoparticles was characterized by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The Debye-Scherrer equation was used to calculate particle sizes and the silver nanoparticles of approximate size 40 nm were observed. The process of reduction is extracellular, which makes it an easier method for the synthesis of silver nanoparticles. (C) 2008 Elsevier B.V. All rights reserved.