An Investigation into the Additional Potential of Iron-Reducing Bacteria Harnessed for Gold Nanoparticle Synthesis

Abstract

Soil bacteria that synthesize varying metallic NPs are underreported, even though there is a promising mechanism in the bio-reduction of gold salts and the synthesis of gold nanoparticles by different bacterial species. This study aimed to explore the ancillary potential of some soil microbes obtained from a metal fabricating workshop for gold nanoparticles (AuNPs) synthesis. To evaluate the usefulness of these soil microbes, 1mM chloroauric acid (HAuCl4.4H2O) was bio-reduced using the wet biomass of these bacterial cells and characterized with UV-Vis spectrophotometer, Fourier Transform Infra-red (FTIR), Scanning Electron Microscope [SEM), Energy Dispersive X-ray (EDX), and X-ray Diffractometer (XRD). The study findings showed that the studied bacterial isolates synthesized AuNPs with absorbance peaks within the range of 500 and 600 nm. The FTIR analysis showed the involvement of O-H, N-H, and C=O stretch of alcohol, amine, and amide groups, respectively. The SEM images analyzed with Image J reported a mean area size between 17-184 nm. The EDX showed Klebsiella africana (C11), and Bacillus subtilis (A12) had the lowest (7.32%) and highest (51.26 %) weight percentages of AuNPs, respectively. Gold nanoparticles have been found most appropriate for several novel applications, and this work has provided further understanding of the capacity of naturally occurring bacteria to be non-selective in the bio-reduction of gold salts, hence expanding their potential uses.