Desulforudis

Desulforudis audaxviator

Desulforudis audaxviator is a bacterium that lives at depths of 1.5 km to 3 km below the earth's surface in the groundwater. Noteworthy in this bacterium is that its metabolism is not only chemotroph, so is without sunlight, but that no organic compounds are required as a hydrogen source also. The energy of a proton gradient generated by the bacteria, the reduction of sulfate to sulfide. Only the electrons in the radiolysis divided by the radiation from radioactive elements water into hydrogen and hydrogen peroxide are available. The metabolism and energy production are therefore completely independent of sunlight and other chemical energy carriers and are based on geological processes in the Earth's interior. Desulforudis audaxviator is a typical representative of endolithisch living organisms.

These Gram- positive bacteria were found in groundwater below a depth of 1.5 km. The deep drilling took place in the Witwatersrand (South Africa) in gold and platinum mines. In a first taxonomic classification they were put to the Firmicutes. In the scheme of the bacteria they are not yet recognized as a species, but have the status as Candidatus.

The specific epithet audaxviator comes from a quote from Jules Verne's Journey to the Center of the Earth. The hero of the story, Professor Lidenbrock, finds a secret inscription which reads in Latin: Descende, audax viator, et terrestre centrum attinges ( Go down, daring traveler, and you will reach the center of the earth ). The geoscientist Tullis Onstott C., dealing at Princeton University with Geomicrobiology, suggested the name.

Habitat

The habitats of these bacteria have been around for some 25 million years isolated from the surface. At a depth of 2800 meters, were examined from the water sample, there is a temperature of about 60 ° C, there is little free oxygen. The genome of the bacterium, consisting of 2175 genes, allows the organism to maintain all life processes, even under prolonged isolation of light and air of the earth's surface. In addition, there is no other living species in this ecosystem. Desulforudis audaxviator is the only living component in this system. However, it was shown that the also occurring in extreme habitats nematode Halicephalobus mephisto in the laboratory preferably fed by Desulforudis audaxviator if he has a choice ( Alternative: E. coli).

It is believed that similar processes of life in the interior of other celestial bodies could play under similar geological conditions as on Earth.