What type of bacteria do not require oxygen for growth?

Anaerobic bacteria are characterized by their ability to grow and thrive in environments devoid of oxygen. They have metabolic pathways that do not depend on oxygen for energy production and can utilize alternative electron acceptors, or in some cases, they derive energy through fermentation processes. This adaptation allows them to inhabit various ecosystems, including those that are oxygen-free, such as deep tissues, contaminated wounds, and the gastrointestinal tracts of animals.

In contrast, aerobic bacteria require oxygen for their growth and metabolism, as they utilize it for cellular respiration. Facultative bacteria possess the flexibility to grow either in the presence or absence of oxygen, switching their metabolic processes according to the environmental conditions. Microaerophilic bacteria require lower levels of oxygen than atmospheric concentrations for optimal growth, positioning them somewhere between aerobic and anaerobic bacteria. However, it is the anaerobic bacteria that explicitly do not require oxygen to thrive, making them distinct in their growth requirements.