FIG 7.

Proposed model depicting how the roles of cbb₃ oxidases differ depending on the environment. Under oxic conditions, cbb₃ oxidases support energy conservation through oxygen reduction, resulting in aerobic biofilm formation. On the other hand, under anoxic denitrifying conditions, cbb₃ oxidases lead to NO accumulation during the denitrification process. NO promotes cell elongation and subsequent anaerobic biofilm formation. It is unclear how cbb₃ oxidases induce NO accumulation.