The Industrially Significant Brevibacillus laterosporus Strain for the Production of Biogenic Silver-Containing Nanoparticles: Analysis of Physicochemical, Biological, and Antimicrobial Characteristics of Nanomaterial

Abstract—The Brevibacillus laterosporus strain with a high level of bactericidal and fungicidal activity was used for the first time for the biosynthesis of silver-containing nanoparticles of various compositions. Nanomaterial samples were obtained by reduction of Ag⁺ from AgNO₃ solution or by a chemical reaction between Na₂S₂O₃ and AgNO₃ in the presence of B. laterosporus cells. When assessing the chemical composition and crystal structure of the nanomaterial, it was found that the shape of the nanocrystals was close to spherical, and the particle sizes varied from 2 to 15 nm, with an average value of 5–7 nm. The values of the ζ-potentials of the samples were close and were –23…–25 mV. The dimensions of the hydrodynamic diameter indicated the presence of a bio-layer on the surface of nanocrystals of various types. The presence of proteins on the surface of nanoparticles was established by electrophoresis, and the selectivity of sorption of protein molecules of various molecular weights from the culture liquid of B. laterosporus on their surface was shown. Several proteins have been identified by mass spectroscopy. A difference in the level of biocidal activity of silver and silver sulfide nanoparticles formed in the presence of B. laterosporus cells was found in relation to gram(+) and gram(–) bacteria and yeast.