Extracellular Biosynthesis of Gold Nanoparticles using Salmonella typhi

The biosynthesis of gold nanoparticles (GNPs) is demonstrated using Salmonella typhi cell exudates. The optimum parameters for the synthesis of nanoparticles were found to be inherent pH of the extract (7.35), high temperature (100ºC) and 100 ppm aurochlorate. The results were verified by UV-Visible spectroscopy, High Resolution Transmission Electron Microscopy (HRTEM) and X-Ray diffraction (XRD) studies. HRTEM images showed that the nanoparticles were roughly spherical and in the range of 10-15 nm. The crystalline nature of the GNPs was confirmed using XRD. The Nitrate reductase activity was found to be 1.330 mmole/min/ml of bacterial exudates that got reduced to 0.24 mmole/min/ml (in the solution) after the formation of GNPs. This result exhibited the involvement of nitrate reductases in the formation of GNPs.

Author(s): Goldie Oza, Sunil Pandey, Ashmi Mewada and Madhuri Sharon

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