A Microbial fuel cell (MFC) or biological fuel cell is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature.
A microbial fuel cell is a device that converts chemical energy to electrical energy by the catalytic reaction of microorganisms.
A typical microbial fuel cell consists of anode and cathode compartments separated by a cation specific membrane.
Microbial fuel of potential cells have a number of uses. The first and most obvious is harvesting the electricity produced for a power source.
Generating Electricity:
When micro-organisms consume a substrate such as sugar in aerobic conditions they produce carbon dioxide and water.
Microbial fuel cells use inorganic mediators to tap into the electron transport chain of cells and steal the electrons that are produced. The mediator crosses the outer cell lipid membranes and plasma wall; it then begins to liberate electrons from the electron transport chain that would normally be taken up by oxygen or other intermediates.
The now-reduced mediator exits the cell laden with electrons that it shuttles to an electrode where it deposits them; this electrode becomes the electro-generic anode (negatively charged electrode).
A number of mediators have been suggested for use in microbial fuel cells. These include natural red, methylene blue, thionine or resorfuin.
In order to generate a useful current it is necessary to create a complete circuit, not just shuttle electrons to a single point.