chemoheterotrophy

Chemoheterotrophy is a metabolic mode in which organisms obtain energy by the oxidation of chemical compounds and acquire their carbon from organic compounds. In this strategy, organisms do not fix carbon dioxide for biosynthesis but rely on preformed organic matter from the environment or a host.

The energy source is chemical rather than light (as in photosynthesis). Most chemoheterotrophs derive energy by oxidizing organic substrates and generate ATP through respiration or fermentation.

Examples include nearly all animals and fungi, as well as many bacteria and some protists. Common laboratory examples are Escherichia coli and Saccharomyces cerevisiae. Chemoheterotrophs can vary in their physiology, but they share reliance on organic carbon sources.

Ecological roles include decomposition, nutrient cycling, and pathogenesis. Chemoheterotrophs range from free-living saprotrophs that break down organic matter to parasitic and mutualistic symbionts that obtain nutrients from hosts.

Chemoheterotrophy is one of several strategies for obtaining energy and carbon. It contrasts with photoautotrophy and photoheterotrophy (energy from light) and with chemolithoautotrophy and chemolithoheterotrophy (carbon or energy derived from inorganic compounds).