Microaerophilic.html



Aerobic and anaerobic bacteria can be identified by growing them in liquid culture:
1: Obligate aerobic (oxygen-needing) bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen.
2: Obligate anaerobic bacteria gather at the bottom to avoid oxygen.
3: Facultative bacteria gather mostly at the top, since aerobic respiration is the most beneficial one; but as lack of oxygen does not hurt them, they can be found all along the test tube.
4: Microaerophiles gather at the upper part of the test tube but not at the top. They require oxygen but at a low concentration.
5: Aerotolerant bacteria are not affected at all by oxygen, and they are evenly spread along the test tube.

Microaerophilic organisms are a specific type of microorganism (especially bacteria) that requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the atmosphere (~20% concentration). Many microphiles are also capnophiles, as they require an elevated concentration of carbon dioxide. (In the laboratory they can be easily cultivated in a candle jar, a container into which a lit candle is introduced before sealing the airtight lid. The flame burns until extinguished by oxygen deprivation, creating a carbon dioxide-rich, oxygen-poor atmosphere.)

Examples include Borrelia burgdorferi, a species of spirochaete bacteria that causes Lyme disease in humans, and Helicobacter pylori, a species of proteobacteria that has been linked to peptic ulcers and some types of gastritis.

See also

• Aerotolerant organism
• Aerobic organism
• Anaerobic organism
• Facultative anaerobic organism
• Fermentation (biochemistry)

External links

• Characterization of an unclassified microaerophilic bacterium associated with gastroenteritis.

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