Is the citric acid aerobic or anaerobic? I know that the oxygen is required to accept the NADH electrons so that NAD+ could be regenerated. Nevertheless, if other electron acceptors, as nitrate (NO3-), are present, could they also be used to regenerate the NAD+? I am asking this because I read a thesis claiming that "acetly-CoA enters the citric acid cycle and through anaerobic nitrate-respiration a multiple amount of ATP is generated." If you have some literature that you can share with me I would be really grateful. Thanks.