Biosynthesis and structural characterization of selenium nanoparticles mediated by Zooglea ramigera

•Selenium nanoparticles (Se-NPs) are synthesized using bacteria Zooglea ramigera.•The biologically synthesized Se-NPs are in the size range of 30–150 nm.•The biogenic Se-NPs are spherical in shape and crystalline in nature.•The possible mechanism of bacterial reduction of selenium oxyanions to Se0 is explained.•Formation of selenium nanorods (t-Se) is observed.

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.

Graphical abstractBacteria Zooglea ramigera mediated biosynthesis of selenium nanoparticles was performed successfully. The biosynthesized nanoparticles were spherical in shape with the size range of 30 to 150 nm. The formation of trigonal selenium nanorods was also observed by the biosynthesis process.Figure optionsDownload full-size imageDownload as PowerPoint slide