The present invention relates to microbial fuel cells, which can be prepared from easily available starting material. The microbial fuel cell of the present disclosure comprises an anode chamber having an anode and a cathode chamber having a cathode. The anode chamber is filled with a mixture comprising a buffer solution, nutrients and a microbial inoculum. The cathode chamber is filled with a catholyte mediator and an electron mediator. The cathode chamber and the anode chamber are connected with each other via a salt bridge; the cathode and the anode is connected through an external electrical circuit, with the anode chamber sealed to maintain anaerobic condition and the cathode chamber is maintained in aerobic condition.