Biosynthesis of gold nanoparticles by Bacillus marisflavi and its potential in catalytic dye degradation

Abstract

The development of an eco-friendly protocol for the synthesis of nanomaterial is an important aspect of research in nanotechnology. This is the first report describing a greener approach for the extracellular synthesis of gold nanoparticles using Bacillus marisflavi YCIS MN 5. The addition of gold chloride solution into a cell-free extract (CFE) of B. marisflavi resulted in the synthesis of gold nanoparticles at room temperature within 96h. The biosynthesized gold nanoparticles were thoroughly characterized by physicochemical characterization techniques. The synthesized nanoparticles were found to be crystalline and spherical with an average size in the range of ∼14nm. The CFE acted both as reducing and stabilizing agents; hence, no additional capping and the stabilizing agents were needed. These gold nanoparticles were assessed for catalytic reduction of Congo red and methylene blue. It was established that the reduction reaction follows pseudo-first order kinetics with a reaction rate constant of 0.2192and0.2484min−1 for Congo red and methylene blue, respectively. Thus, the synthesized gold nanoparticles were found to show outstanding catalytic activity in the degradation of Congo red and methylene blue. The degraded products were identified by Gas chromatography-mass spectroscopy (GC-MS) after the degradation of Congo red and methylene blue. These results suggest B. marisflavi mediated synthesized gold nanoparticles as a promising nano-catalyst in the degradation of Congo red and methylene blue.