Synthetic dyes are extensively used in a number of industries, such as textile dyeing. Due to their low
biodegradability, they cause serious environmental pollution. Thus, in the present paper a partially purified
acid fungal laccase from the white-rot basidiomycete Coriolopsis gallica was entrapped into
calcium alginate beads and applied to the decolorization of different synthetic dyes. Effects of immobilization
conditions such as alginate concentration, CaCl2 concentration and the ratio enzyme/alginate
(E/A) on the loading efficiency and immobilization yield were investigated. The optimal conditions for
C. gallica laccase immobilization into Ca-alginate beads were 2% (w/v) sodium alginate, 2% (w/v) CaCl2,
and 1:4 E/A (v/v). It was also found that laccase stability to pH and temperature increased after
immobilization.
Both the free and immobilized laccase alone showed a high efficiency to decolorize the anthraquinone
dye Remazol Brilliant Blue R (RBBR) while a low decolorization yield was observed for the diazo dyes
Reactive Black 5 (RB5) and Bismark Brown R (BBR) and the metal textile dye Lanaset Grey G (LG). The
addition of the redox mediator 1-hydroxybenzotriazole (HBT) to the decolorization reaction increased
significantly dye removal. The immobilized laccase retained 70% of its activity after four successive
decolorization cycles except for BBR (51.2%). The results obtained showed that the immobilized laccase
from C. gallica has potential for its application in dyestuff treatment.