Anaerobic organism

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Anaerobic organism

An anaerobic organism is any organism

Organism

In biology, an organism is any life thing . In at least some form, all organisms are capable of response to stimulus , reproduction, growth and developmental biology, and maintenance of homeostasis as a stable whole....
that does not require oxygen

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
for growth and may even die in its presence.

Microaerophile

Microaerophile

Microaerophilic organisms are a specific type of microorganism that requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the Earth's atmosphere ....
s are organisms that use oxygen, but only concentrations (low micromolar range); their growth is inhibited by normal oxygen concentrations (approximately 200 micromolar). Nanaerobe

Nanaerobe

Nanaerobes are organisms that cannot grow in the presence of micromolar concentrations of oxygen, but can grow with and benefit from the presence of nanomolar concentrations of oxygen ....
s are organisms that cannot grow in the presence of micromolar concentrations of oxygen, but can grow with and benefit from lower (nanomolar) concentrations of oxygen.

Obligate anaerobes may use fermentation

Fermentation (biochemistry)

Fermentation is the process of deriving energy from the Redox of organic compounds, such as carbohydrates, using an Endogeny electron acceptor, which is usually an organic compound....
or anaerobic respiration

Anaerobic respiration

Anaerobic respiration is the process of generating energy through cellular respiration , without the use of oxygen....
.

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Classification

Obligate anaerobe
Obligate anaerobe

Obligate anaerobes are anaerobic organisms which fail to grow in the presence of oxygen.Obligate anaerobes die in presence of oxygen due to the absence of the enzymes superoxide dismutase and catalase which would convert the lethal superoxide formed in their cells due to the presence of oxygen....
s will die when exposed to atmospheric levels of oxygen.
Facultative anaerobe
Facultative anaerobic organism

A facultative anaerobic organism is an organism, usually a bacterium, that makes Adenosine triphosphate by aerobic respiration if oxygen is present but is also capable of switching to Fermentation ....
s can use oxygen when it is present.
Aerotolerant organisms can survive in the presence of oxygen, but are anaerobic because they do not use oxygen as a terminal electron acceptor.

Microaerophile

Nanaerobe

Fermentation (biochemistry)

Anaerobic respiration

Anaerobic respiration is the process of generating energy through cellular respiration , without the use of oxygen....
. In the presence of oxygen, facultative anaerobes use aerobic respiration; without oxygen some of them ferment, some use anaerobic respiration. Aerotolerant organisms are strictly fermentative. Microaerophiles carry out aerobic respiration, and some of them can also perform anaerobic respiration. Obligate Anaerobes are found in oxygen-free environments such as marshes and in the intestines of many animals, including humans

Human

A human being, also human or man, is a member of a species of bipedalism primates in the family Hominidae . Mitochondrial DNA evidence indicates that modern humans originated in east Africa about 200,000 years ago....
.

Fermentative anaerobes

There are many anaerobic fermentative reactions.

Fermentative anaerobic organisms mostly use the lactic acid fermentation

Fermentation

Fermentation may refer to:* Fermentation , the process of energy production in a cell under anaerobic conditions * Ethanol fermentation, a form of anaerobic respiration used primarily by yeasts when oxygen is not present in sufficient quantity for normal cellular respiration...
pathway:

C₆H₁₂O₆

Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
+ 2 ADP

Adenosine diphosphate

Adenosine diphosphate, abbreviated ADP, is a nucleotide. It is an ester of pyrophosphoric acid with the nucleoside adenosine. ADP consists of the pyrophosphate Functional group, the pentose sugar ribose, and the nucleobase adenine....
+ 2 phosphate ? 2 lactic acid

Lactic acid

Lactic acid , also known as milk acid, is a chemical compound that plays a role in several biochemistry processes. It was first isolated in 1780 by a Swedish chemist, Carl Wilhelm Scheele, and is a carboxylic acid with a chemical formula of C3H6O3....
+ 2 ATP

Adenosine triphosphate

This article is about the chemical used by cells as an energy carrier. For other uses, see ATP .Adenosine-5'-triphosphate is a multifunctional nucleotide, and plays an important role in cell biology as a coenzyme that is the "molecule unit of currency" of intracellular energy transfer....

The energy released in this equation is approximately 150 kJ per mol, which is conserved in regenerating two ATP from ADP per glucose. This is only 5% of the energy per sugar molecule that the typical aerobic reaction generates.

Plants and fungi (e.g., yeasts) generally use alcohol (ethanol) fermentation when oxygen becomes limiting:

C₆H₁₂O₆ + 2 ADP + 2 phosphate ? 2 C₂H₅OH + 2 CO₂ + 2 ATP

The energy released is about 180 kJ per mol, which is conserved in regenerating two ATP from ADP per glucose.

Anaerobic bacteria and archaea

Archaea

The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon . Archaea, like bacteria, are prokaryotic....
use these and many other fermentative pathways, e.g., propionic acid

Propionic acid

Propionic acid is a naturally-occurring carboxylic acid with chemical formula CarbonHydrogen3CH2COxygenOH. In the pure state, it is a colorless liquid with a pungent odor....
fermentation, butyric acid

Butyric acid

Butyric acid , also known under the systematic name butanoic acid, is a carboxylic acid with the structural formula carbonhydrogen3CH2CH2-carboxyl group....
fermentation, solvent fermentation, mixed acid fermentation, butanediol fermentation

Butanediol fermentation

2,3-Butanediol fermentation is anaerobic fermentation of glucose with 2,3-butanediol as one of the end products. The overall stoichiometry of the reaction isButanediol fermentation is typical for Enterobacter and is tested for using the Voges-Proskauer test....
, Stickland fermentation

Stickland fermentation

Stickland fermentation is the name for a chemical reaction that involves the coupled oxidation and Redox of amino acids to organic acids. The electron donor amino acid is oxidised to a volatile carboxylic acid one carbon atom shorter than the original amino acid....
, acetogenesis

Acetogenesis

Acetogenesis is a process through which acetate is produced by anaerobic bacteria from a variety of energy and carbon sources. The different bacterial species that are capable of acetogenesis are collectively termed acetogens....
or methanogenesis

Methanogenesis

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....
.

Some anaerobic bacteria produce toxin

Toxin

A toxin is a poisonous substance produced by living cells or organisms. For a toxic substance not produced by living organisms, "toxicant" is the more appropriate term, and "toxics" is an acceptable plural....
s (e.g., tetanus

Tetanus

Tetanus, also called lockjaw, is a medical condition characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, Anaerobic organism Clostridium tetani....
or botulinum toxin

Botulinum toxin

Botulinum toxin is a medication and a neurotoxic protein produced by the bacterium Clostridium botulinum. It is the most toxic protein known with an LD50 of roughly 0.005-0.05 ?g/kg....
s) that are highly dangerous to higher organisms, including humans.

Obligate anaerobes

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....
into harmless water and O₂.

Culturing anaerobes

Given that normal microbial culturing is undertaken in an aerobic environment, the culturing of anaerobes poses a problem. To overcome this, a number of techniques are employed by microbiologists. One way required the injection of the bacteria into a Dicot. The Dicot would then provide an environment without oxygen thus ensuring the survival of the anaerobes. The GasPak System is an isolated container which achieves an anaerobic environment by the reaction of water with sodium borohydride

Sodium borohydride

Sodium borohydride, also known as sodium tetrahydroborate, has the chemical formula sodiumboronhydrogen4. This white solid, usually encountered as a powder, is a specialty reducing agent used in the manufacture of Pharmacologys and other organic and inorganic compounds....
and sodium bicarbonate

Sodium bicarbonate

Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula NaHCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder....
tablets to produce hydrogen gas and carbon dioxide. Hydrogen then reacts with oxygen gas on a palladium catalyst to produce more water, thereby removing oxygen gas. The issue with the Gaspak method is that an adverse reaction can take place where the bacteria may die which is why a thioglycollate medium should be used. The Thioglycollate supplied a medium mimicing that of a Dicot thus providing not only an anaerobic environment but all the nutrients needed for the bacteria to thrive.

Anaerobic organism

Classification

Fermentative anaerobes

Obligate anaerobes

Culturing anaerobes

See also