Green synthesis and characterization of silver sulfide nanoparticles using Bacillus safensis strain GMS10 isolated from contaminated soil of gold mine

This study aimed to isolate and identify the silver-resistant bacteria and investigation on their potential in the biological synthesis of silver sulfide nanoparticles (Ag2SNPs).

Preliminary characterization of the Ag2SNPs was carried out using visual observations and UV–Visible spectroscopy. Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) was used to determine size, morphology, and elemental analysis of the nanoparticles. Fourier-transform infrared spectroscopy (FTIR) analysis was performed to determine the functional groups that are involved in the bioreduction of silver sulfate into Ag2SNPs.

Based on the results, Bacillus safensis strain GMS10 with highest tolerance to silver sulfate (50 mM) was able to synthesize spherical shape of Ag2SNPs with an average size diameter of 22.2 nm under optimized conditions (1 mM silver sulfate, 15 g/L biomass) after 36 hours incubation. This study is the first report on the synthesis of Ag2SNPs using B. safensis.