Use of microorganisms to recover metals from water bodies and create catalysts on their basis

Abstract

The study aimed to demonstrate the sorption ability of Paracoccus yeei VKM B-3302 cells to remove palladium nanoparticles from aqueous media. An important feature of this study was the size distribution analysis of palladium nanoparticles depending on the method used to store Paracoccus yeei VKM B-3302 cells after culture. The average diameter of palladium nanoparticles formed with the use of native (non-frozen) microbial cells was found to be equal to 3.99±0.03 nm, whereas in the case of microorganisms frozen at temperatures of minus 4 °С and minus 20 °С, it increased to 4.3±0.1 and 4.5±0.6 nm, respectively. These observations highlight the important role of the viability of Paracoccus yeei VKM B-3302 cells in the formation and stabilization of palladium nanoparticles, as well as in the determination of their size characteristics. The produced biohybrid materials exhibit pronounced catalytic activity and can be effectively used in Mizoroki – Heck cross-coupling reactions, which confirms their high functional significance. It is assumed that the retention and stabilization of palladium nanoparticles are ensured by a complex of chemical interactions, including amide bonds in proteins and carboxyl and amino groups of amino acids, as well as glycosidic bonds in polysaccharides, lipids, and peptidoglycan, which are part of the cell envelope. These components create a multifunctional matrix that enables reliable fixation and activity of nanoparticles.