What type of bacteria does not require oxygen to grow or survive?

Anaerobic bacteria are uniquely adapted to grow and thrive in environments devoid of oxygen. These bacteria possess metabolic processes that allow them to derive energy from organic or inorganic compounds without needing oxygen as a terminal electron acceptor. This characteristic makes them essential in various ecological systems, particularly in the breakdown of organic matter and in certain medical contexts where infections are caused by anaerobic pathogens.

In contrast, aerobic bacteria require oxygen for their metabolic processes, as they utilize it in cellular respiration to produce energy. Facultative bacteria can adapt to either aerobic or anaerobic conditions, switching their metabolic processes based on the availability of oxygen, while microaerophilic bacteria thrive in environments with low levels of oxygen but still require some oxygen to survive. This distinction underscores why anaerobic bacteria are classified separately and are critical in settings where oxygen is limited.