Crude laccase from Lentinus polychrous Lev. was entrapped in alginate beads for application in decolorization of synthetic dyes. The percentages of alginate, types and concentrations of bivalent cations (Cu²⁺, Zn²⁺, Ca²⁺) influenced on immobilized enzyme activity as well as immobilized yield. The sensitivity of the immobilized Cu-alginate enzyme towards pH change was lowest when compared to the immobilized enzymes of other bivalent cations including free enzyme. By using ABTS substrate, the optimum temperature of the Ca-, Cu- and Zn-alginate enzymes were 60, 55 and 55°C, respectively while the optimum temperature of the free enzyme was 50°C. The Cu- and Zn-alginate enzymes were well stabilized for a week in all tested pH values except for pH 8.0 (0.1 M Tris-HCl). The Cu- and Zn-alginate enzymes revealed better temperature stability than the Ca-alginate and the free enzymes. Decolorizations of four structurally different synthetic dyes by the immobilized Cu-alginate enzymes in a continuous pack-bed approach were reported. The Cu-alginate enzymes were being able to repeated use effectively more than two times in dye removal experiments. © 2009 Asian Network for Scientific Information.