<P> Obligate anaerobes are microorganisms killed by normal atmospheric concentrations of oxygen ( 20.95 % O ) . Oxygen tolerance varies between species , some capable of surviving in up to 8 % oxygen , others losing viability unless the oxygen concentration is less than 0.5 % . An important distinction needs to be made here between the obligate anaerobes and the microaerophiles . Microaerophiles , like the obligate anaerobes , are damaged by normal atmospheric concentrations of oxygen . However , microaerophiles metabolise energy aerobically , and obligate anaerobes metabolise energy anaerobically . Microaerophiles therefore require oxygen ( typically 2 -- 10 % O ) for growth . Obligate anaerobes do not . </P>
<P> Obligate anaerobes are microorganisms killed by normal atmospheric concentrations of oxygen ( 20.95 % O ) . Oxygen tolerance varies between species , some capable of surviving in up to 8 % oxygen , others losing viability unless the oxygen concentration is less than 0.5 % . An important distinction needs to be made here between the obligate anaerobes and the microaerophiles . Microaerophiles , like the obligate anaerobes , are damaged by normal atmospheric concentrations of oxygen . However , microaerophiles metabolise energy aerobically , and obligate anaerobes metabolise energy anaerobically . Microaerophiles therefore require oxygen ( typically 2 -- 10 % O ) for growth . Obligate anaerobes do not . </P>
obligate anaerobic bacteria may be killed by high doses of
obligate anaerobic bacteria may be killed by high doses of
oxygen
oxygen