Of special importance for biohydrometallurgy are acidophilic chemolithotrophic bacteria from a number of different taxonomic groups, namely: the genera of Thiobacillus and Leptospirillum, moderately thermophilic bacteria which we combined into the group Sulfobacillus-Alicyclobacillus, and archaea of the genera Sulfolobus, Acidianus, Metallosphaera, and Sulfurococcus. These bacteria are able to oxidize one or more of the following compounds Fe+2, S-0 and sulfide minerals and to grow under extreme environmental conditions. Growth pH varies in the range from 1 to 5, growth temprature - from 2 to 90 degrees C. They can tolerate high concentration of metal ions. They possess a great physiological, biochemical and genetic variability. Some of them are important for removal of inorganic sulfur compounds from coals. Some types of coals and oils contain aromatic heterocyclic compounds with the C-S bond. Although a wide range of mostly heterotrophic and some chemolithotrophic bacteria, from bacteria and archaea to eucaryotes, participate in its transformation, only certain organisms have a unique capability of splitting this bond, which is impossible to be done by chemical means. They can remove organic sulfur-containing compounds from coal. The possibilities of application of bacteria in biological processing of coals is discussed.