What are obligate anaerobes unable to do?

Obligate anaerobes are organisms that cannot survive or grow in the presence of molecular oxygen. This is because they lack the necessary enzymes, such as catalase and superoxide dismutase, to detoxify harmful byproducts that are produced when exposed to oxygen. As a result, their metabolic processes are geared towards environments that are completely devoid of oxygen. They typically rely on anaerobic respiration or fermentation to produce energy.

In contrast, many aerobic and facultative anaerobic organisms can use oxygen for their metabolic processes, which allows them to thrive in a variety of environments. This distinct characteristic of obligate anaerobes highlights their adaptation to specific ecological niches where oxygen is absent, such as deep sediments, the digestive tracts of animals, and anaerobic environments created in certain soil types.