İnvestigation of laccase production capacity of newly isolated trametes trogii: İmmobilization and characterization of laccase enzyme

Different fermentation methods were used to produce laccase by newly isolated Trametes trogii strain. This strain produced high amounts of laccase especially in copper-containing media, as an inducer. It was able to produce high levels of laccase even in copper-free media during the solid state fermentation process. A single laccase band was observed in all media. In the study, firstly, the optimum temperature and pH values of the crude free laccase enzyme obtained from the solid state fermentation process were determined. Then, the crude laccase enzyme was immobilized on bacterial cellulose (BC) and optimum temperature and pH values for immobilized laccase were determined. While the free laccase activity was observed to be high in a wide temperature range starting from 25 °C, the optimum pH value was determined to be 3. The optimum temperature for immobilized laccase was determined as 40 °C and the pH value as 4. The stability of both free and immobilized laccase against temperature, pH, organic solvents, heavy metals and sodium chloride as well as storage stability were determined. The effect of inhibitors on free and immobilized laccase activity was also investigated. The immobilized enzyme showed good operational stability. The dye decolorization activity of free and immobilized laccase was also investigated. Free laccase was able to remove the color of Reactive Blue 171, Reactive Blue 198 and Reactive Blue 19 to different extents. The color of Reactive Blue 171 and Reactive Blue 198 could be removed to a high extent during repeatedly use of the immobilized laccase and the number of reuse varied depending on the amount of immobilized laccase used. It was determined that the repeated use activity was low for Reactive Blue 19. As a result; high levels of laccase enzyme could be produced with this strain. Free laccase can be utilized in bioremediation applications. The raw enzyme could be immobilized on BC, a natural polymer, and a stable immobilized laccase can be obtained and used in the removal of various pollutants. Keywords: Bacterial cellulose, enzyme characterization, fermentation, laccase, Trametes trogii, immobilization.