Pseudomonas putida ATCC 49451, a gram negative, unicellular bacterium, is known to be capable of degrading phenol by biotransformation which changes phenol as carbon source to Carbon dioxide as end product. An experiment in a batch system was carried out to look at the degradation phenol in various aeration rate. The pH and temperature were maintained between 7.0-7.5 and 25° C. The results showed some fundamental kinetics data such as specific growth rate, degradation rate (Q) and Yield (Yxs).