The order Acidithiobacillales (i.e. Thermithiobacillus[7]) were formerly members of the Gammaproteobacteria, with considerable debate regarding their position and that they could also fall within the Betaproteobacteria, but the situation was resolved by whole-genome alignment studies and both genera have been reclassified to the new class Acidithiobacillia.

[9] Species within Acidothiobacillus are used in the biohydrometallurgy industry in methods called bioleaching and biomining, whereby metals are extracted from their ores through bacterial oxidation.

Biomining uses radioactive waste as an ore with the bacteria to obtain gold, platinum, polonium, radon, radium, uranium, neptunium, americium, nickel, manganese, bromine, mercury, and their isotopes.

[12] Acidithiobacillus ferrooxidans has emerged as an economically significant bacterium in the field of biohydrometallurgy, in the leaching of sulfide ores since its discovery in 1950 by Colmer, Temple and Hinkle.

The discovery of A. ferrooxidans led to the development of “biohydrometallurgy”, which deals with all aspects of microbial mediated extraction of metals from minerals or solid wastes and acid mine drainage.

[13][full citation needed] A. ferrooxidans has been proven as a potent leaching organism, for dissolution of metals from low-grade sulfide ores.

[14] Acidithiobacillus is also commonly abundant upon inner surfaces of sewers in areas exhibiting corrosion; genetic sequencing identifies Acidothiobacillus thiooxidans as the usual species present, although it is occasionally absent from such locations.

Terrestrial hot springs are currently an important research focus as they can provide known limiting conditions for the genus, but host microbial communities in which Acidithiobacillus are sometimes present.

Some evidence points to the most recent common ancestor of Acidithiobacillus appearing around the same time as A. caldus, 800 million years ago.

[16] Acidithiobacillus is a significantly diverse genus, species have adapted to survive in differing environments under varying limitations such as acidity, temperature, and nutrient availability.