Benzene, toluene and phenol were degraded completely at high initial concentrations by Pseudomonas putida F I ATCC 700007. Two hundred and fifty milligram per litre benzene, 225 mg/l toluene and 200 mg/l phenol were degraded individually in 19, 14 and 3 5 h, respectively. The biodegradation times increased on increasing the substrate concentration. The maximum biodegradation rates were 149 mg benzene/g dry cell h for 60 mg/l benzene, 44 mg toluene/g dry cell h for 110 mg/l toluene and 102 mg phenol/g dry cell h for 100 mg/l phenol. The specific growth rates were 0.530/h for 30 mg/l benzene, 0.410/h for 28 mg/l toluene and 0.037/h for 50 mg/l phenol and decreased on increasing the concentration of these compounds. Cell growth using toluene and benzene as carbon source was better and faster than growth in phenol. These substrates were also biodegraded as binary and tertiary mixtures. The presence of toluene, phenol and toluene-phenol binary mixture increased the biodegradation time of 60 mg/l benzene from 6 to 8, 11 and 8 h respectively. The presence of benzene and/or phenol did not affect significantly the biodegradation time of 55 mg/l toluene. The presence of benzene, toluene and benzene-toluene binary mixture decreased the biodegradation time of 200 mg/l phenol from 35 to 18, 15 and 16 h, respectively. (C) 2002 Published by Elsevier Science Ltd.