From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Scientific classification
Domain: Bacteria
Phylum: Aquificae
Class: Aquificae
Order: Aquificales
Family: Aquificaceae
Genus: Aquifex
Huber & Stetter 1992

A. aeolicus
A. pyrophilus

Aquifex is a genus of bacteria, one of the few in the phylum Aquificae. There is one species of Aquifex with a validly published name - A. pyrophilus - but "A. aeolicus" is sometimes considered as species though it has no standing as a name given it has not been validly or effectively published. Aquifex spp. are extreme thermophiles, growing best at temperature of 85 °C to 95 °C. They are members of the Bacteria as opposed to the other inhabitants of extreme environments, the Archaea.[1]

Aquifex spp. are rod-shaped bacteria with a length of 2 to 6 µm and a diameter of around 0.5 µm. They are non-sporeforming, Gram negative autotrophs. Aquifex means water-maker in Latin, and refers to the fact that its method of respiration creates water. Aquifex tend to form cell aggregates composed of up to 100 individual cells.

Aquifex spp. are thermophilic and often grow near underwater volcanoes or hot springs.[2] A. aeolicus requires oxygen to survive, but can grow in levels of oxygen as low as 7.5 ppm. A. pyrophilus can even grow anaerobically by reducing nitrogen instead of oxygen. Like other thermophilic bacteria, Aquifex has important uses in industrial processes.

The genome of "A. aeolicus" has been completed.[3],[4] This was made easier by the fact that the length of the genome is only about a third of the length of the genome for E. coli. Comparison of the A. aeolicus genome to other organisms showed that around 16% of its genes originated from the Archaea domain. Members of this genus are thought to be some of the earliest members of the eubacteria domain.

"A. aeolicus" was discovered north of Sicily, while A. pyrophilus was first found just north of Iceland.


  1. ^ Reysenbach A-L (2001). Boone DR; Castenholz RW, eds. Aquificae phy. nov. in Bergey’s Manual of Systematic Bacteriology (2nd ed.). Springer-Verlag, Berlin. ISBN 0-683-00603-7. (pp. 359–367).
  2. ^ Madigan M; Martinko J, eds. (2005). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1.
  3. ^ Deckert G; et al. (1998). "The complete genome of the hyperthermophilic bacterium Aquifex aeolicus". Nature. 392 (6674): 353–358. Bibcode:1998Natur.392..353D. doi:10.1038/32831. PMID 9537320.
  4. ^ "The complete genome of Aquifex aeolicus". Aquifex aeolicus VF5 Information. Retrieved 2006-03-14.

External links[edit]

  • Aquifex from the Kenyon College biology department's student-edited microbe wiki.
  • The Prokaryotes: An Evolving Electronic Resource for the Mircobiological Community. 2004. Springer-Verlag New York, LLC.