List of symbols T Temperature M Molecular weight

chig rings was used to study the degradation of toluene in a polluted air stream, by means of a bacterial bio®lm of Pseudomonas putida ATCC 17484. A polluted stream was simulated by blending air with a controlled amount of toluene. The mixing was accomplished in a special mixing chamber designed for that purpose. Induction of the en-zymes of the toluene degradative pathway and adaptation of the inoculum were done in batch cultures with mini-mum mineral media and phenol. The continuous experi-ments were monitored by mass spectrometry for the quanti®cation of the various gases and of toluene removal. A 94 % toluene removal was achieved with contacting times above one minute and toluene concentrations up to 400 ppm