An external loop airlift bioreactor with a small amount (99% porosity) of stainless steel mesh packing inserted in the riser section was used for bioremediation of a phenol-polluted air stream. The packing enhanced volatile organic chemical and oxygen mass transfer rates and provided a large surface area for cell immobilization. Using a pure strain of Pseudomonas putida, fed-batch and continuous runs at three different dilution rates were completed with phenol in the polluted air as the only source of growth substrate. 100% phenol removal was achieved at phenol loading rates up to 33 120 mg h(-1) m(-1) using only one-third of the column, superior to any previously reported biodegradation rates of phenol-polluted air with 100% efficiency. A mathematical model has been developed and is shown to accurately predict the transient and steady-state data. (c) 2006 Society of Chemical Industry.