Аннотация:Pollution of the environment with heavy metals, metalloids, and radionuclides is a global problemthat seriously affects the state of the biosphere. In particular, chromium compounds have toxic, mutagenic, and carcinogenic effects. The main principle of purification of anthropogenic and natural ecosystems from chromates is the reduction of Cr(VI) to Cr(III), whose salts are significantly less toxic and insoluble. However,currently used electrochemical and ion-exchange purification methods are quite expensive and require the use of special reagents. At the same time, sulfate-reducing bacteria (SRB) are of particular interest for bioremediation of this kind, since many of them are very resistant to high concentrations of heavy metals and are able to effectively reduce them in the presence of hydrogen as an electron donor. This review summarizes the known data on the interaction of heavy metals, metalloids, and radionuclides with SRB. The features of the metabolism of these microorganisms that lead to intracellular accumulations of heavy metals and metalloids are considered. Complex and finely regulated enzymatic mechanisms for the reduction of toxic metals(using various cytochromes, hydrogenases, oxidoreductases, highly specific metal reductases, and the thioredoxin/thioredoxin reductase systems), as well as the possibility of using immobilized cells and biofilms of SRB in the effective bioremediation of natural waters, soils, and industrial effluents, are described.
