Microaerophile

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Aerotolerant organisms
do not require oxygen as they metabolise energy anaerobically. Unlike obligate anaerobes however, they are not poisoned by oxygen. They can be found evenly spread throughout the test tube.

A microaerophile is a

capnophiles, requiring an elevated concentration of carbon dioxide (e.g. 10% CO2 in the case of Campylobacter species).[4]

The original definition of a microaerophile has been criticized for being too restrictive and not accurate enough compared to similar categories. The broader term microaerobe has been coined to describe microbes able to respire oxygen "within microoxic environments by using high-affinity terminal oxidase".[1]

Culture

Microaerophiles are traditionally cultivated in candle jars. Candle jars are containers into which a lit

airtight lid. The candle's flame burns until extinguished by oxygen deprivation, creating a carbon dioxide-rich, oxygen-poor atmosphere.[5]

Newer oxystat bioreactor methods allow for more precise control of gas levels in the microaerobic environment, using a probe to measure the oxygen concentration or redox potential in real time.[6] Ways to control oxygen intake include gas-generating packs and gas exchange.[4]

As oxystat bioreactors are expensive to buy and run, lower-cost solutions have been devised. For example, the Micro-Oxygenated Culture Device (MOCD) is a system involving ordinary flasks, oxygen-permeable tubes, sensors, and water pumps. Aeration is done by pumping the culture medium through the tubes.[1]

Examples

A wide variety of microaerobic conditions exist in the world: in human bodies, underwater, etc. Many bacteria from these sources are microaerobes, some of which are also microaerophiles.

See also

References

External links