Synthesis of Ag-Containing Nanoparticles by Shewanella spp. and Genomic Analysis of Shewanella xiamenensis Strain DCB2-1

Abstract This paper presents a comparative analysis of Ag+ reduction to Ag-containing nanoparticles (NPs) by seven Shewanella strains isolated from various environmental sources and belonging to the species S. oneidensis MR-1 (1 strain), S. putrefaciens (4 strains), and S. xiamenensis (2 strains). Depending on the strain, three different types of NPs were produced: Ag, AgCl, or Ag@AgCl NPs. The obtained nanoparticles were characterized by UV‒Vis spectroscopy, XRD, dynamic light scattering, transmission electron microscopy, EDX, atomic emission spectroscopy, and SDS‒PAGE. The strain-dependent differences in the characteristics of the nanomaterials were shown. The bacterial strains synthesized polycrystalline silver-containing nanoparticles of quasi-spherical shape, with sizes ranging from 10 to 20 nm, which formed 50‒200-nm agglomerates. Adsorption of bacterial protein molecules onto the surface of NPs was demonstrated, while the sets of proteins by molecular weight differed depending on the strain. The strains with the highest level of Ag+ reduction were identified. Genome analysis of S. xiamenensis strain DCB2-1 revealed the genes related to NPs synthesis.