Modelling

Mediator Reduction

In Microbial Fuel Cell microorganisms provide the electrons for the anode from the oxidation of the substrate(s) in the intracellular metabolic pathways. The transfer of the electrons to electrodes has been demonstrated for several species, though this process is inefficient as far as Coulombic yield and current generation are concerned [A]. Hence, the application of the electrochemical mediators is essential for the construction of Microbial Fuel Cell. Mediators are usually small water-soluble molecules, which are capable of undergoing the redox transformations. The mediator acts as an electron shuttle, enhancing the kinetics of the electron transfer. This approach has been proven to be generally quite successful and many substances were tested for their potential as electron shuttle. There are two classes of mediators, the endogenous and the exogenous mediator. The endogenous mediators are generated by the bacteria and can be secreted to the medium and then be reduced at the electrode. The exogenous mediators are the redox molecules that are chemically synthesized and must be added into the anode chamber of the Microbial Fuel Cell, in order to enable electron transfer from bacterial metabolic pathways to the anode.

References