Anaerobic respiration
Anaerobic cellular respiration and fermentation generate ATP in very different ways, and the terms should not be treated as synonyms.
The reduced chemical compounds are oxidized by a series of respiratory integral membrane proteins with sequentially increasing reduction potentials, with the final electron acceptor being oxygen (in aerobic respiration) or another chemical substance (in anaerobic respiration).
[citation needed] Fermentation, in contrast, does not use an electrochemical gradient but instead uses only substrate-level phosphorylation to produce ATP.
[citation needed] There are two important anaerobic microbial methane formation pathways, through carbon dioxide / bicarbonate (HCO−3) reduction (respiration) or acetate fermentation.
Like mitochondria in oxygen-respiring microorganisms, some single-cellular anaerobic ciliates use denitrifying endosymbionts to gain energy.
However, uncontrolled methanogenesis in landfill sites releases large amounts of methane into the atmosphere, acting as a potent greenhouse gas.
[7] Specific types of anaerobic respiration are also critical in bioremediation, which uses microorganisms to convert toxic chemicals into less-harmful molecules to clean up contaminated beaches, aquifers, lakes, and oceans.
The reduction of chlorinated chemical pollutants, such as vinyl chloride and carbon tetrachloride, also occurs through anaerobic respiration.
The model above shows the process of anaerobic respiration through denitrification , which uses nitrogen (in the form of nitrate, NO −
3 ) as the electron acceptor. NO −
3 goes through respiratory dehydrogenase and reduces through each step from the ubiquinose through the bc1 complex through the ATP synthase protein as well. Each reductase removes oxygen step by step so that the final product of anaerobic respiration is N 2 .
1. Cytoplasm
2. Periplasm Compare to the aerobic electron transport chain .