The rate and extent of trichloroethylene (TCE) degradation by three cultures of phenol oxidizing bacteria grown from two chemostats and one from rotating biological contactors was investigated. Batch experiments were performed to measure the disappearance of TCE both with the resting cell alone and with the formate added. Experimental data were then compared with mathematical predictions from a model describing TCE transformation. Through nonlinear regression analysis, a best fit between the measurements and predictions was achieved when residual sum of squares reached a minimum. Based on the resultant parameters of transformation capacity and reaction rate, the suspended cells with a mean cell retention time (MCRT) of 3.8 days were the most active in degrading TCE, while the attached bacteria had the least activity. Based on the results presented herein, it is recommend that using suspended‐growth reactors operated at short MCRT to produce desirable cells for cometablic transformation of TCE.