Solid state cultures of two white-rot fungi, Phanerochaete chrysosporium and Phlebia radiata, have been carried out, using an inert support (nylon sponge) and a support-substrate (corncob). The suitable medium and culture conditions have been chosen to favour the secretion of ligninolytic enzymes. The production of manganese peroxidase, lignin peroxidase, laccase and proteases has been monitored during the cultures. in an attempt to investigate the possible effect of the latter on the integrity of ligninolytic enzymes. The higher the protease concentration in the culture medium, the more irregular the profiles of ligninolytic enzyme activity. P. chrysosporium secretes proteolytic enzymes mainly during primary metabolism. while P. radiata produced these at the onset of secondary metabolism. Furthermore, different types of proteases produced were identified, P. chrysosporium secreted mainly thiol and acidic proteases, while P. radiata cultures contained thiol-, serin- and metalloproteases. (C) 2002 Elsevier Science Ltd. All rights reserved.