[2] Considered to be one of the most common microbes involved in biomining, it is capable of oxidizing reduced inorganic sulfur compounds (RISCs) that form during the breakdown of sulfide minerals.

[3] The meaning of the prefix acidi- in the name Acidithiobacillus comes from the Latin word acidus, signifying that members of this genus love a sour, acidic environment.

Thiobacillus caldus was reclassified into Acidithiobacillus, one of three new genera (also including Halothiobacillus and Thermithiobacillus) created to further classify members of the genus which fall into the alpha-, beta-, and gamma-classes of the Pseudomonadota.

[1] A. caldus, originally isolated from spoils of unneeded rocks encountered when mining coal, was the first acidophilic species of thermophilic thiobacilli to be described.

[2] A genetic basis is thought to exist for the extreme temperature tolerance shown by A. caldus as compared to other species in its genus, such as A. ferrooxidans and A.

[1] The growth of A. caldus is enhanced when the air used for sparging, a process by which bubbles of a chemically inert gas are pumped through a liquid, is supplemented with 2% (w/v) CO2.

[2] Neither 0.05% yeast extract (a yeast product formed when a cell's walls are removed and its internal contents are extracted[7]), casamino acids (an amino acid/peptide mixture common to microbial growth media formed from the acid hydrolysis of casein[8]), nor a 2.5 mM concentration of glucose as the sole substrate have been shown to induce heterotrophic growth of A. caldus.

[1] Strains of A. caldus have been differentiated from other related acidithiobacilli, including A. ferrooxidans and A. thiooxidans, by sequence analyses of the PCR-amplified 16S-23S rDNA intergenic spacer (ITS) and restriction fragment length polymorphism.

The 16S-23S rDNA spacer region is a useful target for developing molecular methods that focus on the detection, rapid differentiation, and identification of Acidithiobacillus species.