Wastewaters containing dyes are toxic pollutants released to environment, which can be dangerous for living organisms and human health. They can cause various diseases, for example cancers, allergies and neurological disorders. Many industries, such as textile and automotive industries generate huge amounts of wastewaters, in which huge amounts of dyes in presented. There are a number of methods used to remove dyes from aqueous solutions, such as adsorption, sedimentation, coagulation, membrane techniques or photocatalysis, however biodegradation deserves special attention. It is a dyes removal technique in which the main degradation factors are microorganisms and/or enzymes. Especially for dyes conversion, enzymes such as laccases, tyrosinases and peroxidases are the most frequently used. These oxidoreductases, which are widespread in nature, catalyse the oxidation of a wide variety of substrates, such as dyes, pharmaceuticals and other phenolic compounds. Nevertheless, in order to increase the biodegradation efficiency and improve enzymes stability, the immobilization process is carried out using support of various origin. It should be emphasized that selection of the suitable support material is a crucial step in enzyme immobilization.
In the presented work, the Remazol Brilliant Blue R (RBBR) textile dye was degraded using laccase from Trametes versicolor immobilized inorganic onto oxide systems such as: TiO2-ZrO2, TiO2-ZrO2-SiO2, ZrO2-SiO2 and ZrO2-SiO2 modified by copper ions. Based on the obtained results, it was confirmed that the laccase was immobilized successfully. Furthermore, effect of the support type, concentration of dye solution as well as pH and temperature conditions on the efficiency of enzymatic decolorization were evaluated using UV-Vis spectroscopy. What is more, it was found that obtained biocatalytic systems might be reuse in successive degradation cycles due to the improvement of the laccase stability.