A fresh pipette was used for each dilution and the work was performed in the laminar air flow cabinet, under sterile condition.Nutrient agar plates containing chlorpyrifos (50 mg/L) were used for determining the viable count of resistant colonies. The bacterial cells visible to the naked eyes were counted in terms of CFUs. All the plating was performed in triplicates and results were represented as mean. The viable count was obtained from this value by reference to the serial dilution used. Growth response study of chlorpyrifos-degrading bacteria