The overall characteristics of a BOD biosensor are determined by the characteristics of the microbial membranes used in combination with the electrochemical sensor. First amongst them is the effect of cell population on BOD values. A number of BOD biosensors have been developed using single organism or a random combination of organisms, but mixed cultures are shown to be an efficient biodegrading agent for organic compounds in aqueous solution, with good kinetics, sensitivity, stability and reproducibility. Keeping this in view, a formulated microbial consortium, developed and extensively tested with a wide range of synthetic as well as industrial wastewaters was used as biocatalyst for the construction of the BOD biosensors in the present study.