define facultative anaerobe
Facultative anaerobe. Definition. noun. An organism which is capable of producing energy through aerobic respiration and then switching back to anaerobic respiration depending on the amounts of oxygen and fermentable material in the environment. Supplement.rganisms in the Kingdom Fungi can also be facultative anaerobic, such as yeasts. Word origin: an-from Gk., not, without, + Greek Äero -, from ÄÄr, air. Compare: obligate anaerobe. See also: facultative anaerobe, microaerophile, aerotolerant.