Biosynthesis of silver nanoparticles by a bacterial strain isolated from gold mine

چکیده مقاله

Introduction Various microorganisms (bacteria, yeast, fungi) are applied to synthesize silver nanoparticles. The produced nanoparticles have different size and shape. Microbial synthesis of nanoparticles has a potential to develop simple, cost- effective and eco-friendly methods for production of technologically important materials (2). Methods Soil samples were collected from heavy metal contaminated areas of Gold mine, Iran. Samples were used as the source material for bacterial isolation. The samples were serially diluted in sterile 0.8 % NaCl and then plated onto nutrient agar (1). A bacterial strain isolated from gold mine were selected for the synthesis of AgNPs. On treating the bacteria with 1mM AgNO3, it was found to have the ability to form AgNPs extracellularly at room temperature within 24 h. The colour change observed for the extracellular samples were further confirmed by UV–Vis spectral analysis as part of primary confirmation. Characterization of synthesized AgNPs was done by Scanning electron microscopy (SEM). Result In the current study, a bacterial strain isolated from heavy metal contaminated soil samples was found to have resistance to silver nitrate. This was confirmed by formation of brown colour and the visual observation and UV–Vis absorption at 450 nm. Further characterization of nanoparticles by SEM confirmed. Size of silver nanoparticles were 200-300 nm. Discussion These biogenic nanoparticles are cost-effective, simpler to synthesize and the method is greener in approach.