Acidithiobacillus

Acidithiobacillus is a genus of Gram-negative, acidophilic, chemolithoautotrophic bacteria that derive energy from the oxidation of ferrous iron or reduced inorganic sulfur compounds and fix carbon dioxide.

They are commonly found in acidic environments such as acid mine drainage, ore deposits, and bioleaching heaps, where they contribute to the natural cycling of iron and sulfur and can accelerate mineral dissolution.

Iron-oxidizing species oxidize Fe2+ to Fe3+, while sulfur-oxidizing species oxidize reduced sulfur compounds to sulfate. Some strains exhibit both capabilities. Rusticyanin, a copper-containing protein, is involved in iron oxidation in some members.

Notable species include Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Acidithiobacillus caldus; other members include A. ferriphilus and A. ferrivorans. The genus was established to reclassify several acidophilic lithotrophs previously placed in Thiobacillus.

In industry, they are central to bioleaching of metal sulfides and influence the chemistry of acid mine drainage, while research explores their applications in bioremediation and ecological studies.