Reference Work Entry

Encyclopedia of Astrobiology

pp 289-291


  • Ricardo AmilsAffiliated withDepartamento de Planetología y Habitabilidad Centro de Astrobiología (CSIC-INTA), Universidad Autónoma de Madrid Campus Cantoblanco Email author 




A chemolithotroph is an organism that is able to use inorganic reduced compounds as a source of energy. This mode of metabolism is known as chemolithotrophy.


Chemolithotrophy​ was discovered by Winogradsky while studying the microorganisms involved in the oxidation of sulfur compounds.


Chemolithotrophy is found only in prokaryotes and is widely distributed among Bacteria and Archaea. The spectrum of inorganic compounds that can be used as electron donors by chemolithotrophs is rather broad (H2S, S0, S2O32−, H2, Fe2+, NO2or NH3). Some microorganisms are rather specific regarding the inorganic substrates they can use to generate energy, while others are able to use different compounds (versatile). The best characterized chemolithotrophs are aerobic respirers, which use oxygen as the electron acceptor, although the list of chemolithotrophs capable of employing anaerobic respiration is increasing rapidly. Chemo ...

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