Thermodynamic prognosis of the efficiency of toxic metals extraction from solution by microorganisms and their genetic potential

Abstract

Aim. Thermodynamic justification of pathways of microbial interaction with metals and development of theoretical foundations of novel biotechnologies for purification of industrial waste water from environmentally hazardous metals-oxidizers (CrО42-, MoО42-, WО42-). Methods. The fields of stability of metal compounds in aqueous solutions in the coordinates of pH-Eh were calculated using classic Pourbaix diagrams. The effectiveness of metals extraction from solutions was evaluated according to Gibbs free energy. Results. On the base of thermodynamic calculations conditions and efficiency of metals extraction by microorganisms was shown. Microbial reduction of CrО42- to insoluble Cr(III) hydroxide was the most effective. Additional carbon and energy sources are required for effective molybdate reduction. Extraction of tungstate can not be carried out by microorganisms. Conclusions. Thermodynamic prognosis is effective method for developing novel environmental biotechnologies for purification of environmentally hazardous metal-containing wastewater and simultaneous treatment of organic waste.
 Keywords: thermodynamic prognosis, microbial interaction of with metals, metals extraction,
 purification of metal-containing wastewater, environmental biotechnologies.