An increasing demand of lignin-degrading enzymes makes an effective enrichment of laccase C from culture broth necessary. In this work, the continuous foam fractionation of laccase C was investigated as an alternative to other common applied methods, such as salting-out, dialyses or ultratiltration, which are usually accompanied by losses of catalytic activity or low operational capacity. After optimization of different process parameters (feed position, gas flow rate and surfactant concentration) an enrichment ratio of 11.7 was achieved for laccase C along with 70.2% recovery. Feed position at the top of the foaming column increased the recovery. Increasing the gas flow rate led to a lower enrichment but higher recovery, and an increased outlet flow rate had only negative effect on the recovery. With increasing concentration of cetyl trimethyl ammonium bromide (CTAB), which was applied as a surfactant to enable foaming, the enrichment ratio decreased (from 11.7 to 1.8) and recovery increased (from 70.2 up to 80.2%). A for the enrichment ratio and recovery optimum CTAB-concentration of 0.4 mg/ml was found. The method has been proven to be effective for the enrichment of laccase C. (c) 2005 Elsevier B.V. All rights reserved.