It is known, that many microorganisms actively participate in formation of mineral resources buried within the earth, as well as on seabed and ocean floor, where large deposits of iron, manganese, copper, nickel, cobalt and other metals have been discovered. Bacteria also facilitate leaching and recovery of various metals from ores. Microorganisms transform compounds that contain practically all elements forming base and rare metals' minerals. In recent years, owing to close cooperation between geologists, miners, ore-dressers, metallurgists and microbiologists, a new scientific and practical trend is being created — microbiological hydrometallurgy. The authors tried to generalize the theoretical basics of bacterial leaching, laying special stress on microbiological conditioning of bauxites. A possibility of partial removal of sulfur and iron from bauxites has been shown. A special feature in the work is assigned to silicate bacteria (silicius), owing to unusual character of their feeding. An assumption is supported that cell life-sustaining process constitutes biochemical oxidation of inorganic substrate, that proceeds with transport of electrons from a lower-potential silicate system to a higher-potential organic structure of cell itself. Data are presented with regard to silicon dioxide and aluminosilicates resistance in biogenous leaching. The results of beneficiation by mechanical processing methods are presented for comparison. The main disadvantage of bacterial leaching remains to be low rate of bacterial processes, and practicability of wide commercial application of chemolithotrophs bacteria at the present stage is still problematical.

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