Rapid synthesis of silver nanoparticles using culture supernatants of Enterobacteria:: A novel biological approach

The development of reliable processes for the synthesis of silver nanomaterials is an important aspect of current nanotechnology research. Reports on the cell-associated biosynthesis of silver nanoparticles using microorganisms have been published, but these methods of synthesis are rather slow. In this paper, we report on the rapid synthesis of metallic nanoparticles of silver using the reduction of aqueous Ag+ ion using the culture supernatants of Klebsiella pneumonia, Escherichia coli, and Enterobacter cloacae (Enterobacteriacae). The synthetic process was quite fast and silver nanoparticles were formed within 5 min of silver ion coming in contact with the cell filtrate. Through a limited screening process involving a number of common microorganisms, we observed that the culture supernatants of different bacteria from Enterobacteriacae were potential candidates for the rapid synthesis of silver nanoparticles; further, we revealed that tbi method of synthesis requires far less time than previously published biological methods. Our investigation also showed that piperitone can partially inhibit the reduction of Ag+ to metallic silver nanoparticles by Enterobacteriacae. (C) 2007 Elsevier Ltd. All rights reserved.