obligate anaerobe

…the absence of oxygen are obligate, or strict, anaerobes. Some species, called facultative anaerobes, are able to grow either with or without free oxygen. Certain others, able to grow best in the presence of low amounts of oxygen, are called microaerophiles.

…methane-producing archaea (methanogens), are called obligate anaerobes because their energy-generating metabolic processes are not coupled with the consumption of oxygen. In fact, the presence of oxygen actually poisons some of their key enzymes. Some bacteria (S. pneumoniae) are microaerophilic or aerotolerant anaerobes because they grow better in low concentrations of…

…of oxygen and are called obligate anaerobes. Facultative anaerobes are bacteria that can grow in both the presence or absence of oxygen. In addition to oxygen concentration, the oxygen reduction potential of the growth medium influences bacterial growth. The oxygen reduction potential is a relative measure of the oxidizing or…