User:Sdenviogeo/Facultative anaerobic organism

Article body
Facultative anaerobes are able to grow in both the presence and absence of oxygen due to the expression of both aerobic and anaerobic respiratory chains using either oxygen or an alternative electron acceptor. For example, in the absence of oxygen, E. coli can use fumarate, nitrate, nitrite, dimethyl sulfoxide, or trimethylamine oxide as an electron acceptor.

The ability of facultative anaerobic pathogens to survive without oxygen is important since their infection is shown to reduce oxygen levels in their host's gut tissue. Moreover, the ability of facultative anaerobes to limit oxygen levels at infection sites is beneficial to them and other bacteria, as dioxygen can form reactive oxygen species (ROS). These species are toxic to bacteria and can damage their DNA, among other constituents.