A formulated, synergistic and pre-tested microbial consortium used as a reference seeding material for BOD analysis was incorporated as the biocomponent in the developed BOD sensor. The microorganisms comprising the microbial consortium were harvested in their log phase of growth from the respective broth cultures. The cell pellet was suspended in 50 mM phosphate buffer solution (pH 6.8) to obtain the cell slurry. This cell slurry was immobilized on charged nylon membrane by filtering small aliquots under moderate vacuum. The immobilized microbial membrane prepared in the above said manner was left to dry for 18–20 h at room temperature. Finally, the dried membranes were transferred in buffer solution and kept at 4 °C, till further use. The immobilized microbial membrane was then coupled to the electrode by holding the membrane against the teflon gas permeable membrane by means of a nylon net to get a complete electrode assembly. The response of the electrode was measured in term of current (nA) obtained on a multimeter.