Thiobacillus ferrooxidans sulfur compound oxidation

Thiobacillus ferrooxidans is an obligate chemoautotrophic and acidophilic organism and is able to oxidize Fe2+, S°, metal sulfides, and other reduced inorganic sulfur compounds. Thiobacillus thiooxidans has also been isolated from acid mine wastes and has been determined that can oxidize both elemental sulfur and sulfide to sulfuric acid (S° + 1.502 + H20 - H2S04 and S2 + 202 + 2H+ - H2S04) (Brierley, 1982 Lundgren and Silver, 1980). However, T. thiooxidans cannot oxidize Fe2+ (Harrison, 1984). 

Rusticyanin is found in Thiobacillus ferrooxidans, an acidophilic, chemolithotrophic sulfur bacterium utilizing Fe + and reduced sulfur compounds as its sole energy source. T. ferrooxidans does not produce rusticyanin when grown on reduced sulfur. Similar to other substrate-inducible cupredoxms, the msticyanin gene is activated when soluble iron is present in the media. Little is known about its redox partners and it should be noted that rusticyanin itself does not carry out Fe + oxidation. Other iron-oxidizing bacteria, for example, Leptospirillum ferrooxidans, prodnce a cytochrome which substitutes rusticyanin functionally. To date T. ferrooxidans remains the only source for rusticyanin. 

This principal environmental problem posed by coal-cleaning waste is that the pyrite and marcasite in the waste are oxidized to sulfuric acid in the presenee of air, water, Ferrobacillus ferrooxidans, and Thiobacillus ferrooxidans. The sulfuric acid is usually sufficiently concentrated to dissolve numerous metallic constituents and large quantities of iron from the pyrite in the leachate. Any ECT intended to prevent sulfuric acid formation must eliminate either the air, the water, or the oxidizable sulfur compounds in the waste, or inactive Ferrobacillus ferrooxidans and Thiobacillus ferrooxidans by maintaining alkaline conditions. Post-treatment of pile drainage comprises ECTs designed to neutralize the acid in the effluent and remove the metal ions by some sort of precipitation, adsorption, flocculation, or ion-exchange phenomenon. 

Landesman, J., Duncan, D.W. and Walden, C.C., 1966b. Oxidation of inorganic sulfur compounds by washed cell suspensions of Thiobacillus ferrooxidans. Can. J. Microbiol., 12 957-964. 

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