The production of laccase by Trametes versicolor in airlift bioreactors was studied. In order to enhance laccase production several inducers were tested, among which 2,5-xylidine led, by far, to the highest activities (around 1500 U/l). The bioreactor operated in two successive batches for 40 days with no operational problems and pellets of regular size were maintained throughout the fermentation. The bioreactor configuration employed is appropriate for laccase production by free cells of T versicolor. The extracellular liquid obtained was studied in terms of pH and temperature activity and stability. The ligninolytic fluid produced was fully active at pH 3 and 60 degreesC. Moreover, it was stable at pH 5 and retained about 70% activity at 30 degreesC for 12 days. In addition, it was able to decolourise the sulphonephthalein dye Phenol Red. This decolourisation was most efficient at pH 5. (C) 2003 Elsevier Science Ltd. All rights reserved.