The Influence of Bacterial Strains Used to Produce Cadmium Sulfide Nanoparticles on the Level of Biocidal Activity of the Nanomaterial

Abstract

In this work, we report on the effect of Shewanella oneidensis MR-1 and Bacillus subtilis 168 bacteria used for the biosynthesis of CdS nanoparticles (CdS NPs) on the level of antimicrobial activity of CdS NPs/Shewanella and CdS NPs/Bacillus against a wide range of microorganisms: gram-positive, gram-negative bacteria, yeast and mold fungi. It is shown that S. oneidensis MR-1 and B. subtilis determine the quantitative characteristics of the nanomaterial, the content of protein and the CdS fraction in CdS NP samples. The use of the atomic emission spectroscopy method to determine the elemental content of cadmium and sulfur, as well as the densitometric analysis of electropherograms of protein adsorbed on the surface of biogenic CdS NPs demonstrate a significant difference in the ratio of these components in CdS NPs/Shewanella and CdS NPs/Bacillus. It is found that the proportion of CdS in CdS NPs/Bacillus exceeds by 1.4 times this parameter for CdS NPs/Shewanella. At the same time, the proportion of protein in CdS NPs/Bacillus is reduced compared to CdS NPs/Shewanella. It is shown that the level of antimicrobial activity of CdS NPs/Bacillus in relation to all test cultures studied exceeds the same parameter for CdS NPs/Shewanella. It is assumed that an increase in the proportion of CdS in CdS NPs/Bacillus may be the cause of a higher level of biocidal activity of CdS NPs due to an increased amount of released Cd2+ ions, which lead to the generation of reactive oxygen species and the destruction of microbial cells. Thus, the importance and necessity of selecting bacterial strains for the creation of functionally active nanoparticles with optimal characteristics is proved. The results of this research confirm the prospects of utilizing biogenic CdS NPs as targeted antimicrobial agents.