''Alicyclobacillus acidocaldarius'' is a species of

Gram positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain i ...

, strictly aerobic,

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

. The bacteria are acidophilic, thermophilic, and produce endospores. The first identified strains of ''A. acidocaldarius'' were from

geyser A geyser (, ) is a spring with an intermittent water discharge ejected turbulently and accompanied by steam. The formation of geysers is fairly rare and is caused by particular hydrogeological conditions that exist only in a few places on Ea ...

s in

Yellowstone National Park Yellowstone National Park is a List of national parks of the United States, national park of the United States located in the northwest corner of Wyoming, with small portions extending into Montana and Idaho. It was established by the 42nd U ...

and

fumerole A fumarole (or fumerole) is a vent in the surface of the Earth or another rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

soil in Hawaii Volcano National Park. The species was originally classified as ''Bacillus acidocaldarius'' in 1971, but further

16S rRNA 16S ribosomal RNA (or 16Svedberg, S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome (SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The genes coding for it are referred to as ...

studies found that the species belonged in the newly created genus ''Alicyclobacillus''. The species name is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''acidum'' (acid) and ''caldarius'' (pertaining to warm or hot), referring to the acidic and high temperature environments from which it was first isolated. Thomas D. Brock was one of the researchers who first categorized the species; his discovery of ''

Thermus aquaticus ''Thermus aquaticus'' is a species of bacteria that can tolerate high temperatures, one of several thermophile, thermophilic bacteria that belong to the ''Deinococcota'' phylum. It is the source of the heat-resistant enzyme Taq polymerase, ''Taq' ...

'' allowed for other researchers to discover

Taq polymerase ''Taq'' polymerase is a thermostable DNA polymerase I named after the thermophilic eubacterial microorganism ''Thermus aquaticus,'' from which it was originally isolated by master's student Alice Chien et al. in 1976. Its name is often abbr ...

and polyermase chain reaction (PCR). A strain of ''A. acidocaldarius'' has been isolated from thermally heated soils of Mount Rittmann in Antarctica. ''Alicyclobacillus acidocaldarius'' was among the first three species reclassified from the genus ''

Bacillus ''Bacillus'', from Latin "bacillus", meaning "little staff, wand", is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum ''Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-sh ...

'' to the newly created ''Alicyclobacillus'' in 1992, along with '' A. acidoterrestris'' and '' A. cycloheptanicus''. The optimum growth temperature for ''A. acidocaldarius'' is 60-65 °C, and can grow in the 45-70 °C range. The optimum pH is 3.0-4.0, and can grow in pH 2.0-6.0.

References

Food microbiology Gram-positive bacteria Bacteria described in 1992 Bacillales {{bacilli-stub