文摘
A crude laccase mixture preparation from Pleurotus ostreatus cultures supplementedwith copper and ferulic acid was used to decolorize the anthraquinonic dye RemazolBrilliant Blue R (RBBR). Performance of this enzymatic system was tested, and amaximum of 70% decolorization was achievable under optimal conditions. The crudepreparation was immobilized by entrapment in copper alginate beads attaining 65%yield of laccase activity. Stability of the immobilized laccases was remarkably increasedin comparison with that of the free enzyme preparation. Efficiency of the immobilizedsystem was evaluated during stepwise dye additions in batch operations. Under thebest conditions, 70% RBBR decolorization was achieved even after 20 cycles, althoughdecolorization time exponentially increased after the 10th cycle. Different fixed-bedbioreactors were prepared and analyzed in continuous decolorization processes. Thebest performance was obtained by decreasing the amount of enzyme loaded and byimproving laccase retention using chitosan-coated alginate beads.