Microbial synthesis of antimony sulfide nanoparticles and their characterization

During recent years, biological synthesis of nanoparticles by microorganisms has been receiving increasing attention. In this investigation, an antimony-transforming bacterium was isolated from the Caspian Sea in northern Iran and was used for intracellular biosynthesis of antimony sulfide nanoparticles. This isolate was identified as non-pigmented Serratia marcescens using conventional identification assays and the 16S rDNA fragment amplification method, and was used to prepare inorganic antimony nanoparticles. The biogenic nanoparticles were released by liquid nitrogen and extracted using two sequential solvent extraction systems. Different characterizations of the extracted inorganic nanoparticles such as particle shape, size and composition were carried out with different instruments. The energy-dispersive x-ray demonstrated that the extracted nanoparticles consisted of antimony and sulfur atoms. In addition, the transmission electron micrograph showed the small and regular non-aggregated nanoparticles ranging in size less than 35 nm. Although the chemical synthesis of antimony sulfide nanoparticles has been reported in the literature, the biological synthesis of antimony sulfide nanoparticles has not previously been published. This is the first report to demonstrate a biological method for synthesizing inorganic nanoparticles composed of antimony. A simple extraction method for isolation of antimony sulfide nanoparticles from bacterial biomass is also reported in the current investigation.