Термодинамическое прогнозирование редокс-взаимодействия микроорганизмов с металлами-окислителями (Hg2+, CrO2−и Cu2+)

Abstract

The results of thermodynamic calculations providing a basic opportunity of growth of microorganisms at ultrahigh concentrations of toxic oxidative metals such as Hg2+, CrO2− 4 , and Cu2+ are given. At a manifold increase in the concentration of metals (from 1·10−8 up to 1.0 mole/l), their standard redox-potential (E0) increases only by 200. . . 400 mV and does not fall outside the limits of thermodynamic stability of water. In the presence of Hg (II), Cr (VI), and Cu (II), the growth of microorganisms is theoretically admissible even at their 1-mole concentration (ac- cordingly, 10000, 51996, and 63540 ppm). Toxicity of Hg2+, CrO2− 4 , Cu2+ for microorganisms is defined, first of all, by their high redox-potential (+920, +555, and +440 mV, accordingly). Metabolic activity of chemoorganotrophic microorganisms is accompanied by a decrease in the redox-potential of the environment up to −200 · · ·− 400 mV. Microorganisms serve as donors, and oxidative metals as acceptors of electrons. The potential difference between the donor (−200. . .−400 mV) and acceptor systems (+440 . . .+920 mV) is equal to 660. . .1320 mV and predetermines the reduction of Hg2+, CrO2− 4 , and Cu2+ by microorganisms.