Fenian Cycle | Nitrogen fixation | National Cycle Network | nitrogen | Cardiac cycle | 24-hour news cycle | The Kentucky Cycle | The Baroque Cycle | nitrogen oxide | Dream Cycle | Cycle World | Ulster Cycle | Stirling cycle | Segregated cycle facilities | Post-Vulgate Cycle | Biological life cycle | Tillerman Cycle | The Riftwar Cycle | The Prayer Cycle | solar cycle | Reynolds Cycle Technology | Otto cycle | nitrogen fixation | National Cycle Route 73 | National Cycle Route 1 | Motor Cycle News | Inheritance Cycle | Giovanni Baleison, ''Cycle on the life of Saint Sebastian'', fresco, detail of main altar, St. Sebastian Church, Saint-Étienne-de-Tinée | Combined cycle | Classic cycle races |
Denitrifying bacteria form a necessary part of the process known as denitrification as part of the nitrogen cycle, their primary purpose being to metabolise nitrogenous compounds, with the assistance of the nitrate reductase enzyme, to turn oxides back to nitrogen gas or nitrous oxides for energy generation.