What is the Difference Between Obligate and Facultative Anaerobe?

The main difference between obligate and facultative anaerobes lies in their ability to tolerate and grow in the presence of oxygen:

Obligate anaerobes are microorganisms that cannot live in the presence of oxygen, as they lack the enzymes necessary to neutralize the toxic byproducts of oxygen. They are killed by average atmospheric concentrations of oxygen and require a strict oxygen-free environment to survive and grow.
Facultative anaerobes are microorganisms that prefer to live in the presence of oxygen but can also survive without it. They can switch between aerobic respiration and anaerobic respiration or fermentation, depending on the availability of oxygen.

In summary:

Obligate anaerobes cannot tolerate oxygen and require a strict oxygen-free environment.
Facultative anaerobes can tolerate oxygen and can switch between aerobic and anaerobic respiration.

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What is the Difference Between Obligate and Facultative Anaerobe?

Comparative Table: Obligate vs Facultative Anaerobe

Here is a table comparing the differences between obligate and facultative anaerobes:

Feature	Obligate Anaerobe	Facultative Anaerobe
Oxygen Requirement	Strictly anaerobic, requires an oxygen-free environment	Can live and grow in the presence or absence of oxygen
Oxygen Tolerance	Killed by oxygen, as it is poisonous to them	Can survive in the presence of oxygen but can also grow without it
Enzymes	Lack enzymes such as superoxide dismutase and catalase, which are necessary to counteract oxygen's toxic effects	Possess some oxygen-handling enzymes, allowing them to tolerate oxygen when it is present
Examples	Corynebacterium and Shewanella oneidensis	Staphylococci and Enterobacteriaceae
Habitat	Found in environments with low oxygen concentrations, such as deep-sea hydrothermal vents and the intestinal tract of animals	Can be found in various environments, including the skin and upper respiratory tract (for staphylococci) and the gut and upper respiratory tract (for Enterobacteriaceae)
Laboratory Study	Requires special equipment, such as an anaerobic jar, to study them in an oxygen-free environment	Can be studied more easily in a typical laboratory setting without the need for special equipment

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.