Abstract:
Microbial fuel cell (MFC) system, converts the chemical energy of organic
biodegradable waste and wastewater to electrical energy with the catalytic activity of
bacteria. Microbial fuel cell generally consists three parts i.e., cathode, anodic chambers and
a proton exchanger. Degradation of organic substrates through microorganism takes place in
anodic chamber that generates free electrons and H+ ions under anaerobic condition.
In MFC electrons and protons travels through an external circuit and a salt
bridge/PEM respectively. In anodic chamber electrons travels to the anode electrode surface
through direct or indirect route or Direct route involves physical contact between MFC
membranes with anode surface and electron transfer takes place through cytochrome, and in
indirect route microbes excreted or externally added mediator is used.
Efficiency of MFC depends upon mainly anodic/cathodic pH, initial substrates COD
concentration, temperature, material of electrodes, trace minerals and presence of mediator
etc. However, higher or lower concentration of metal ions may responsible to enhance
toxicity, sustainability of bacteria so that optimum values of these factors required for
valuable performance of MFCs. Further, the coefficient of electron transfer from anode to
catode may create difference in solution pHs because coefficient of no. Of H+ ions or
coefficient of electrons from anode to cathode through salt bridge/membrane may differ to
same extent. In the anodic chamber, biodegradable organic substances are oxidized through
microorganisms as equation (1) and transfer the electrons to anode electrode (negative
electrode).
