[The biology of bacteria used to treat industrial sewage to remove heavy metals]

The content of heavy metals in the water bodies increases as a result of anthropogenic effects. Heavy metals exert toxical effect on hydrobionts. Involved into the trophic chain they can be the cause of grave human diseases. Microorganisms possess a capacity to accumulate heavy metals in their body, evoke the process of their enzymatic transformation into nontoxical compounds and adsorb them on the cell surface. When breeding bacterial strains for the biological treatment of sewage from the metal-working plants the authors recommend to choose the cultures from econiches containing heavy metal compounds and to establish their resistance to high concentrations of metals. This resistance correlates with high biological activity. The bacterial strains of Pseudomonas genus possessing a capacity to sulphate reduction have been selected. As a result of their activity the high-solvable toxical sulphates are restored to practically unsolvable precipitating forms. A new species Aeromonas dechromatica transforming high-toxical six-valence chromium into low-toxical three-valent ones is described. The grounds of biotechnologies of the use of the breeded cultures for treatment of industrial sewage are stated.