What type of bacteria can survive in environments lacking oxygen?

Anaerobic bacteria are specifically adapted to thrive in environments where oxygen is not available. These microorganisms utilize fermentation or anaerobic respiration to generate energy, which allows them to grow and reproduce in low-oxygen or oxygen-free conditions. This adaptability enables them to inhabit various environments, such as deep soils, sediments, and the gastrointestinal tracts of some animals, where oxygen levels are minimal or nonexistent.

In contrast, aerobic bacteria require oxygen for survival, utilizing it in their metabolic processes. Facultative anaerobes have the ability to switch between aerobic and anaerobic metabolism, depending on the availability of oxygen, allowing them to survive in both environments. Therefore, while both facultative anaerobes and anaerobic bacteria can exist in low-oxygen conditions, the distinguishing feature of anaerobic bacteria is that they thrive exclusively without oxygen. The statement that all bacteria require oxygen is misleading, as many bacteria, particularly anaerobes, can successfully grow in its absence.