chemolithoautotróf

A chemolithoautotroph is an organism that obtains energy from the oxidation of inorganic compounds and uses carbon dioxide as its primary source of carbon. These microorganisms are found in a wide range of environments, particularly those where sunlight is absent or limited, such as deep-sea hydrothermal vents, soil, and subsurface rock formations. The "chemo" prefix indicates that they derive energy from chemical reactions, "litho" refers to their use of inorganic compounds as electron donors, and "autotroph" signifies their ability to synthesize organic compounds from inorganic carbon, typically carbon dioxide.

The energy-generating inorganic compounds utilized by chemolithoautotrophs vary greatly and include substances like hydrogen sulfide, ammonia, ferrous iron, and elemental sulfur. The specific metabolic pathways employed depend on the available inorganic energy sources and the organism's evolutionary history. For example, sulfur-oxidizing bacteria use reduced sulfur compounds, while nitrifying bacteria oxidize ammonia. These metabolic processes often involve complex electron transport chains, similar in principle to those found in photosynthetic organisms, but utilizing different electron donors and acceptors.

Chemolithoautotrophs play crucial roles in biogeochemical cycles, particularly those involving nitrogen, sulfur, and iron. They are essential for nutrient cycling in ecosystems and can contribute to processes like mineral weathering and the formation of geological deposits. Their ability to thrive in extreme environments also makes them subjects of interest in astrobiology, as they represent potential models for life that could exist on other planets.