Lithoautotroph

Microbe which derives energy from minerals
A lithoautotroph is an organism which derives energy from reactions of reduced compounds of mineral (inorganic) origin. Two types of lithoautotrophs are distinguished by their energy source; photolithoautotrophs derive their energy from light while chemolithoautotrophs (chemolithotrophs or chemoautotrophs) derive their energy from chemical reactions.]] Lithoautotrophs are extremely specific in their source of reduced compounds. Thus, despite the diversity in using inorganic compounds that lithoautotrophs exhibit as a group, one particular lithoautotroph would use only one type of inorganic molecule to get its energy. A chemolithotrophic example are Anaerobic Ammonia Oxidizing Bacteria (ANAMMOX), which use ammonia and nitrite to produce N2.

Some chemolithotrophs use redox half reactions with low reduction potentials for their metabolisms, meaning that they do not harvest a lot of energy compared to organisms that use organotrophic pathways. Lithoautotrophs may be present in the deep terrestrial subsurface (they have been found well over 3 km below the surface of the planet), in soils, and in endolith communities. As they are responsible for the liberation of many crucial nutrients, and participate in the formation of soil, lithoautotrophs play a crucial role in the maintenance of life on Earth. For example, the Nitrogen cycle is influenced by the activity of ammonium oxidizing archaea, ANAMMOX bacteria, and Complete Ammonium Oxidizing (COMAMMOX) bacteria of the genus Nitrospira. Acid mine drainage drastically alters the acidity and chemistry of groundwater and streams, and may endanger plant and animal populations. Activity similar to acid mine drainage, but on a much lower scale, is also found in natural conditions such as the rocky beds of glaciers, in soil and talus, and in the deep subsurface.