For the production of complex, valuable molecules, microorganisms usually have to breathe with oxygen in biotech processes in order to have enough energy for product formation. The biotechnological production of complex products from anaerobic microorganisms or of oxygen-sensitive products, on the other hand, is very difficult. We explore metabolic pathways for anaerobic energy production through breathing with an electrode via natural redox mediators. The focus is on natural phenazine redox mediators and how these are or can be integrated into the energy metabolism of bacteria. The project is funded by an ERC Consolidator Grant from the European Union.