Biogenic formation of various nanostructured materials, including selenium nanoparticles (SeNPs), by live microorganisms, which is widespread in nature, has been increasingly attracting the attention of researchers over the last decade. Selenium as a practical material is an important element in semiconductors with specific physical characteristics such as the anisotropy of thermo-conductivity, high photoconductivity and thermoelectric activities. Because of the biological and industrial properties, SeNPs have wide applications in the fields of medicine, microelectronic, agriculture and animal husbandry. The aim of current study was to use the potential aquatic bacteria as biocatalysts to bioreduce of sodium selenite to selenium nanoparticles (SeNPs).Fifty selenite-resistant bacterial strains screened according to selective enrichment technique. Based on the results, only strain MeSe15 was able to synthesis and accumulates of SeNPs. The strain of MeSe15 was selected as superior strain and identified as Acinetobacter sp. MeSe15 based on phenotypic and phylogenetic analysis. The production of selenium nanoparticles in bioconversion mixture was studied using UV-vis spectroscopy. Se nanoparticles display an optical absorption bond at 430 nm and the presence of elemental selenium was confirmed by Energy dispersive x ray (EDX) analysis. This strain synthesized nanoparticles under a variety of conditions. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) micrographs showed both extra and intra cellular synthesis of Se nanoparticles.
