Facultative bacteria can utilize which type of oxygen?

Facultative bacteria are versatile organisms capable of surviving in both aerobic and anaerobic environments. This means they can utilize both free dissolved oxygen, which is oxygen present in the water, and combined oxygen, which is oxygen that is part of other chemical compounds. In the presence of free dissolved oxygen, facultative bacteria can carry out aerobic respiration, a more energy-efficient process. Conversely, in the absence of oxygen, they can switch to anaerobic respiration or fermentation, utilizing combined oxygen within compounds. This adaptability allows facultative bacteria to thrive in varying conditions, making them an essential component in wastewater treatment processes and natural ecosystems. Thus, they are equipped to utilize both types of oxygen effectively.