Biogenic Fabrication of Gold Nanoparticles using Halomonas salina

Use of microorganisms as novel and eco-friendly approach for biosynthesis of gold nanoparticles by exploiting the reducing and thermodynamically efficient molecular mechanisms of Halomonas salina is reported in the present work. The biosynthesis was significantly impacted by both pH and temperature of the reactants. At lower temperature (30oC) the optimum parameters were pH 9 and 100 ppm of aurochlorate salt for fabrication of thermodynamically stable isotropic nanostructures. Whereas under same conditions pH 4, resulted into anisotropic orchestration of biogenically derived gold nanoparticles of size 30 - 100 nm. The stability of gold nanoparticles was also studied using 5 M NaCl salt. The contribution of nitrate reductase in reducing the gold ions to gold nanoparticles was assayed biochemically. The nitrate reductase activity got drastically reduced from 1.21 mmole/min/ml supernatant to 0.23 mmole/min/ml supernatant; after biogenic fabrication of gold nanoparticles. The morphology and the crystal structure of the gold nanoparticles (GNP) were characterized using electron microscopy and X Ray Diffraction respectively. Keywords: Halomonas salina, Biosynthesis, Gold nanoparticles, Surface Plasmon Resonance, Stability, Nitrate reductase.