An anaerobic organism is any organism that does not require oxygen for growth and may even die in its presence.... s which fail to grow in the presence of oxygen.
Obligate (strict) anaerobes die in presence of oxygen due to the absence of the enzymes superoxide dismutase
Superoxide dismutase
The enzyme superoxide dismutase , catalyzes the dismutation of superoxide into oxygen and hydrogen peroxide. As such, it is an important antioxidant defense in nearly all cells exposed to oxygen.... and catalase
Catalase
Catalase is a common enzyme found in nearly all living organisms which are exposed to oxygen, where it functions to catalyst the decomposition of hydrogen peroxide to water and oxygen.... which would convert the lethal superoxide
Superoxide
Superoxide is the anion O2−. It is important as the product of the one-electron reduction of dioxygen, which occurs widely in nature.... formed in their cells due to the presence of oxygen. Instead of oxygen, obligate anaerobes use alternate electron acceptor
Electron acceptor
An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. It is an oxidizing agent that, by virtue of its accepting electrons, is itself reduced in the process.... s for respiration
Respiration
Respiration may refer to:* Respiration , the transport of oxygen to cells where cellular respiration takes place* Gas diffusion in soil, exchange of gases between plant roots and the atmosphere... such as sulfate
Sulfate
In inorganic chemistry, a sulfate is a salt of sulfuric acid.... , nitrate
Nitrate
In inorganic chemistry, a nitrate is a salt of nitric acid with an ion composed of one nitrogen and three oxygen atoms . In organic chemistry the esters of nitric acid and various alcohols are called nitrates.... , iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color.... , manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a Oxidation state in nature , and in many minerals.... , mercury
Mercury (element)
Mercury , also called quicksilver or hydrargyrum , is a chemical element with the symbol Hg and atomic number 80. A heavy, silvery d-block metal, mercury is one of six elements that are liquid at or near room temperature and pressure.... , and carbon monoxide
Carbon monoxide
Carbon monoxide, with the chemical formula CO, is a colorless and odorless, tasteless, yet highly toxic gas. Its molecules consist of one carbon atom covalent bond to one oxygen atom.... . The energy yield of these respiratory processes is less than oxygen respiration, and not all of these electron acceptors are created equal.
The most favorable (after oxygen) is sulfate. In marine sediments this leads to large amounts of sulfate reduction, which most of us are familiar with as the rotten egg smell and black material that can be found just a few centimeters below the sediment surface.
Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens. Organisms capable of producing methane have been identified only from the Kingdom Archaea, a group Phylogenetics distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria.... is found. Very little energy is obtained from methanogenesis and vast amounts of substrate need to be turned over to make a living.
Bacteroides is a genus of Gram-negative, bacillus Bacterium. Bacteroides species are non-endospore-forming, Anaerobic bacteria, and may be either motile or non-motile, depending on the species.... and Clostridium
Clostridium
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores.... species are examples of non-spore forming and spore-forming strict anaerobes, respectively.
