The paper deals with the primary objective to optimize different parameters such as concentration, temperature, pH, time and size of cells for the decolorization of azo dye (Congo red) by using bacterial isolates by the method of immobilized bacterial cells. Staphylococcus aureus immobilized beads show a maximum dye decolorization of 94% under optimum condition and found to be more efficient in dye decolorization. The optimum value for degradation is found to be 35 degrees C, for 400 mg/L of concentration of dye at the medium pH of 7. The order of the reaction was found to be first order with the rate constant of 0.073 h(-1). The dye adsorbed on the bead surface follows Freundlich adsorption isotherm with the constant values are K = 1.368 and 1/n = 0.773. Studies have been carried out by FTIR, GC-MS analysis for confirming the biodegradation of Congo Red by the immobilized bacterial cells. The results reported warrant further investigation to establish the usefulness of these isolates for bioremediation and biodegradation application such as wastewater treatment.