News: At the London Zoo, a fern has started taking its own selfies. This was achieved by installing microbial fuel cells.
Definition: Microbial fuel cells (MFCs) are devices that use bacteria as the catalysts to oxidize organic and inorganic matter and generate current. The idea of using microbes to produce electricity was conceived by M. C. Potter in early 20th century.
- Generally MFC consists of anode and cathode compartments, which are separated by a cationic membrane.
- Microbes reside in the anode compartment, where they metabolize organic compounds such as glucose which act as electron donor. The metabolism of these organic compounds generates electrons and protons.
- Electrons are then transferred to the anode surface. From anode, the electrons move to cathode through the electrical circuit, while the protons migrate through the electrolyte and then through the cationic membrane.
- Electrons and protons are consumed in the cathode by reduction of soluble electron acceptor, such as oxygen or hexacynoferrate and acidic permanganate. Electrical power is harnessed by placing a load between the two electrode compartments.
Applications of MFCs:
- Production of low-cost electricity from waste materials.
- Can be used as an alternate method for bioremediation.
- Can act as a biosensor-can measure the solute concentration of wastewater.
- Can be used in waste-water treatment.