Biosynthesis and structural characterization of selenium nanoparticles mediated by Zooglea ramigera

In the present study, biosynthesis of selenium nanoparticles with non-pathogenic, ecofriendly, easily available bacterium Zooglea ramigera was reported. The bacterium Z. ramigera was grown aerobically with selenium oxyanions (as the electron acceptor). It was formed extracellular, stable, uniform, nanospherical structure of monoclinic crystalline selenium. The biosynthesized selenium nanoparticles were spherical (by TEM) in shape with the size range of 30 nm to 150 nm. The formation of selenium nanorods (trigonal) was also observed. XRD and SAED analyses revealed that synthesized selenium nanoparticles were selenium crystal of the pure hexagonal phase. A hypothetical mechanism for biological synthesis of selenium nanoparticles was also proposed. (C) 2013 Elsevier B.V. All rights reserved.