The effects of biosurfactant dirhamnolipid on the production of lignin peroxidase, manganese peroxidase, CMCase and xylanase from Phanerochaete chrysosporium (P. chrysosporium) in submerged fermentation were tested. The effects of dirhamnolipid were also compared with those of chemical surfactant sodium dodecylsulfate (SDS). The results showed that dirhamnolipid at different concentrations had certain stimulative effects on the activities of CMCase, xylanase and lignin peroxidase, while SDS at different concentrations almost inhibited all the four enzyme activities. At the peak enzyme production phase, dirhamnolipid raised the lignin peroxidase activity by 22-62%. At the highest point, dirhamnolipid at the concentration of 0.0065% (w/v) increased the CMCase activity by 13.25%, and dirhamnolipid at the concentration of 0.013% (w/v) raised the xylanase and lignin peroxidase activities by 16.27% and 61.98%, respectively. (C) 2008 Elsevier Ltd. All rights reserved.