Facultative bacteria can use either molecular (dissolved) oxygen or oxygen obtained from food material such as sulfate or nitrate ions. In other words, facultative bacteria can live under aerobic or anaerobic conditions.
FACULTATIVE (FACK-UL-TAY-TIVE)
Meaning of FACULTATIVE (FACK-UL-TAY-TIVE) in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012