A microbial fuel cell (MFC) or biological fuel cell electrochemical system drives an electric current by using bacteria found in nature. MFC’s can be grouped into two general categories i.e. mediated MFC and unmediated MFC. There are two chambers in the fuel cell i.e. the anodic chamber and the cathodic chamber. Both the electrodes are immersed in the respective chamber for the flow of electrons. Moreover, a salt bridge can be set-up in between the chambers for the flow of protons or a proton exchange membrane (PEM) can also be used. Various types of electrodes can be used according to the requirement. The pencil lead type graphite electrode provides more surface area which results in higher voltages as compared to wire mesh type carbon paper electrodes. Performing different trials for different types of water, electrodes and NaCl concentration an appropriate result can be concluded. By comparing the time and voltages data of trials on a graph, the economical and feasible trial can be selected. The fuel cells can be used for various applications like waste water treatment, generation of current using organic waste as well as can be used as bio-sensors for the determination of Biochemical Oxygen Demand (BOD). The advantages of MFC’s are many but its use for production of electric current from waste is driving people’s attention. Humanity has just touched the surface of MFC’s and there is a vast scope of future development.

Keywords : MFC, Mediated and Unmediated, Salt Bridge, Electric Current, Applications.