chemotrofit

Chemotrophs are organisms that obtain their energy from chemical reactions, rather than from light. They drive their metabolism by transferring electrons during the oxidation or reduction of chemical compounds. This energy source distinguishes them from phototrophs, which rely on light to power their metabolism.

Chemotrophs can be subdivided by their electron donors and by their carbon sources. Electron donors may be inorganic (lithotrophs) or organic (organotrophs). Carbon sources may be inorganic carbon dioxide (autotrophs) or organic carbon compounds (heterotrophs). As a result, chemotrophy includes a range of metabolic strategies such as chemolithoautotrophy, chemolithoheterotrophy, and chemoorganoautotrophy or chemoorganoheterotrophy. Examples of chemolithoautotrophs include Nitrosomonas, which oxidizes ammonia, Nitrobacter, which oxidizes nitrite, and Thiomicrospira, a sulfur-oxidizer. These organisms play key roles in major biogeochemical cycles, including nitrogen, sulfur, and iron cycles, and often inhabit environments such as soils, sediments, and hydrothermal vents.

Chemoorganotrophs obtain energy by oxidizing organic compounds and can include a wide array of bacteria, fungi, and animals. Organisms such as Escherichia coli, Bacillus species, many fungi, and animals are chemoorganotrophs, deriving energy from organic nutrients and typically obtaining carbon from existing organic matter. Many chemotrophs are facultative or obligate aerobes, but a substantial number are anaerobic and use alternative terminal electron acceptors such as nitrate, sulfate, or ferric iron. Chemotrophy is widespread across all domains of life and underpins diverse ecological niches and industrial applications, including wastewater treatment and bioremediation.