anaerobes

(noun)

Organisms that do not require oxygen for growth.

Related Terms

Examples of anaerobes in the following topics:

  • Oxygen

    • Facultative anaerobes can use oxygen, but also have anaerobic (i.e. not requiring oxygen) methods of energy production.
    • An anaerobic organism or anaerobe is any organism that does not require oxygen for growth.
    • For practical purposes there are three categories : obligate anaerobes, which cannot use oxygen for growth and are even harmed by it.
    • And finally, facultative anaerobes, which can grow without oxygen but can utilize oxygen if it is present.
    • Since normal microbial culturing occurs in atmospheric air, which is an aerobic environment, the culturing of anaerobes poses a problem.

  • Anoxic Hydrocarbon Oxidation

    • Anoxic hydrocarbon oxidation can be used to degrade toxic hydrocarbons, such as crude oil, in anaerobic environments.
    • Although it was once thought that hydrocarbon compounds could only be degraded in the presence of oxygen, the discovery of anaerobic hydrocarbon-degrading bacteria and pathways show that the anaerobic degradation of hydrocarbons occurs naturally.
    • Anaerobic oxidation of methane (AOM) is a microbial process that occurs in anoxic marine sediments.
    • It is estimated that almost 90% of all the methane that arises from marine sediments is oxidized anaerobically by this process.
    • Microbes may be used to degrade toxic hydrocarbons in anaerobic environments.

  • Electron Donors and Acceptors in Anaerobic Respiration

    • In anaerobic respiration, a molecule other than oxygen is used as the terminal electron acceptor in the electron transport chain.
    • Anaerobic respiration is the formation of ATP without oxygen.
    • Many different types of electron acceptors may be used for anaerobic respiration.
    • Organic compounds may also be used as electron acceptors in anaerobic respiration.
    • A molecule other than oxygen is used as the terminal electron acceptor in anaerobic respiration.

  • Syntrophy and Methanogenesis

    • Bacteria that perform anaerobic fermentation often partner with methanogenic archea bacteria to provide necessary products such as hydrogen.
    • A frequently cited example of syntrophy are methanogenic archaea bacteria and their partner bacteria that perform anaerobic fermentation.
    • Methanogenesis in microbes is a form of anaerobic respiration, performed by bacteria in the domain Archaea.
    • Without methanogenesis, a great deal of carbon (in the form of fermentation products) would accumulate in anaerobic environments.

  • Anammox

    • Anammox, an abbreviation for ANaerobic AMMonium OXidation, is a globally significant microbial process of the nitrogen cycle.
    • Anammox, an abbreviation for ANaerobic AMMonium OXidation , is a globally significant microbial process of the nitrogen cycle.
    • Since oxygen is not required for the process, these organisms are strict anaerobes.
    • Describe the overall process of ANaerobic AMMonium OXidation (Anammox) and its purpose

  • Methane-Producing Archaea: Methanogens

    • Methanogens are an important group of microoraganisms that produce methane as a metabolic byproduct under anaerobic conditions.
    • Methanogenic archaea, or methanogens, are an important group of microoraganisms that produce methane as a metabolic byproduct under anaerobic conditions.
    • Methanogens play a vital ecological role in anaerobic environments by removing excess hydrogen and fermentation products produced by other forms of anaerobic respiration.

  • Iron Oxidation

    • Ferric iron is an anaerobic terminal electron acceptor, with the final enzyme a ferric iron reductase.
    • Ferric iron (Fe3+) is a widespread anaerobic terminal electron acceptor both for autotrophic and heterotrophic organisms.
    • Ferrous iron is a soluble form of iron that is stable at extremely low pHs or under anaerobic conditions.
    • The third type of iron-oxidizing microbes is anaerobic photosynthetic bacteria such as Rhodopseudomonas, which use ferrous iron to produce NADH for autotrophic carbon dioxide fixation.
    • Outline the purpose of iron oxidation and the three types of ferrous iron-oxidizing microbes (acidophiles, microaerophiles and anaerobic photosynthetic bacteria)

  • Fusobacteria

    • Fusobacterium are anaerobic, non-spore forming, gram-negative bacteria that are associated with periodontal disease and Lemierre's syndrome.
    • Fusobacteria are rod-shaped bacilli capable of thriving in anaerobic conditions.
    • At this point, bacteria which are capable of thriving in anaerobic conditions, such as Fusobacterium necrophorum can flourish deep in the abscess.

  • Microbial Growth Cycle

    • Conversely, obligate anaerobes are killed by oxygen and carry out fermentation.
    • Tetanus is an obligate anaerobe so it will infect areas where oxygen in limited.
    • Aerotolerant anaerobes breath anaerobically (without oxygen), but they are able to survive when oxygen is present.

  • Sulfate and Sulfur Reduction

    • Sulfate reduction is a type of anaerobic respiration that utilizes sulfate as a terminal electron acceptor in the electron transport chain.
    • Sulfate reduction is a type of anaerobic respiration that utilizes sulfate as a terminal electron acceptor in the electron transport chain.
    • All sulfate-reducing organisms are strict anaerobes.
    • Sulfate-reducing bacteria are common in anaerobic environments (such as seawater, sediment, and water rich in decaying organic material) where they aid in the degradation of organic materials.
    • Some sulfate-reducing bacteria play a role in the anaerobic oxidation of methane (CH4 + SO42- → HCO3– + HS– + H2O).