DYE DECOLOURIZATION BY IMMOBILIZED LACCASE AND IMPACT OF AUXILIARY CHEMICALS ON DYE DECOLOURIZATION

Textile dyes are molecules designed to impart a permanent colour to textile fabrics. They pose an environmental problem because they are toxic and they decrease the aesthetic value of rivers and lakes. Current technologies for dye removal cannot remove all classes of dyes and two or more technologies are usually combined to achieve statisfactory decolouriza-tion efficiencies. Lignin-degrading enzymes like laccases are potential technologies for dye decolourization and decolourization with immobilized laccase has been intensively in-vestigated. The majority of those studies however have focused on dye disappearance and several reported that significant dye adsorption had occured during the dye removal, mak-ing the role of the enzyme unclear. Moreover, textile wastewaters contain auxiliary chem-icals that can impact enzymatic dye decolourization and very few studies have evaluated the impact of those substances on laccase. This research evaluated the feasibility of treat-ing dye-contaminated textile wastewaters with an immobilized laccase system. The first sub-objective was to examined the decolourization of Reactive blue 19 (an anthraquinone dye) by Trametes versicolor laccase immobilized on controlled porosity carrier (CPC) sil-