Combined heterotrophic nitrification and aerobic denitrification in Thiosphaera pantotropha and other bacteria

Reports of the simultaneous use of oxygen and denitrification by different species of bacteria have become more common over the past few years. Research with some strains (e.g. Thiosphaera pantotropha) has indicated that there might be a link between this aerobic denitrification and a form of nitrification which requires rather than generates energy and is therefore known as heterotrophic nitrification. This paper reviews recent research into heterotrophic nitrification and aerobic denitrification, and presents a preliminary model which, if verified, will provide at least a partial explanation for the simultaneous occurrence of nitrification and denitrification in some bacteria.