In the present study, phenol present in synthetic wastewater has been biodegraded in a bubble column bioreactor using Pseudomonas putida (NCIM-2650). Experiments have been carried out at various feed flow rates of synthetic wastewater, at a feed concentration of 250 mg/L and air flow rate of 2 Lpm. The effect of internal draft tube height on biodegradation of phenol has also been studied. It is observed that with increase in draft tube height, better performance of the reactor is obtained. Volumetric oxygen mass transfer coefficient and gas holdup have been found to increase when draft tube is used.