Desulforudis audaxviator

Desulforudis audaxviator is a bacterium, which lives in depths from 1,5 km to 3 km below the Earth's surface in the groundwater.

It is a bacterium found in water samples obtained nearly two miles underground in a South African gold mine. This type of bacterium, approximately four micrometers in length, has survived for millions of years on chemical food sources that derive from the radioactive decay of minerals in the surrounding rock, making it one of the few creatures known that does not depend on sunlight for nourishment.

These bacteria are unique. They have been isolated from Earth's surface for several million years, because analyses of the water that they live in showed that it is very old and has not been diluted by surface water. Because the environment at that depth is so much like the early Earth, it gives us a handle on what kind of creatures might have existed before we had an oxygen atmosphere. Many hundreds of millions of years ago, some of the first bacteria on the planet may have thrived in similar conditions. All the newly discovered microbes could shed light on research into the origins of life on Earth.

D. audaxviator is a Gram(+) SRB (making it the first complete such genome).The genome contains an unusual transposon, and possesses many sites of insertion.Loss of complete oxygen tolerance system suggests long-term isolation. The hydrocarbons in that environment do not come from living organisms. The source of the hydrogen needed for their respiration comes from the decomposition of water by Radioactive decay of uranium, thorium, and potassium. The radiation allows for the production of lots of sulfur compounds that these bacteria can use as a high-energy source of food.

The name comes of a quotation from Jules Verne's Journey to the Center of the Earth. The hero of history, professor Lidenbrock, finds a secret inscription in Latin that reads: Descende, audax viator, et terrestre centrum attinges (Descend, bold traveller, and you will attain the center of the earth).