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Copyright of Adiyaman University Journal of Science & Technology / Adıyaman Üniversitesi Fen Bilimleri Dergisi is the property of Adiyaman University, Institute of Science / Adiyaman Universitesi Fen Bilimleri Enstitusu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of incubation time, temperature, initial pH, and dye concentration on the indigo carmine decolorization activity of Pseudomonas aeruginosa ATCC 10145 and some factors on the decolorization potential of crude laccase enzyme obtained from Funalia trogii ATCC 200800 were comparatively investigated. This bacterium showed effective decolorization activity at all agitation and temperature values. Indigo carmine was greatly decolorized by P. aeruginosa at all pH values except pH 10. A decrease in decolorization activity occurred with increasing dye concentration, but this bacterium effectively decolorized the dye within 24 h. The decolorization process was through microbial metabolism, not biosorption. No decolorization or laccase activity could be obtained by the cell-free intracellular extract or culture filtrate of this bacterium. On the other hand, crude laccase effectively decolorized indigo carmine under highly acidic conditions, especially at pH 3.0 as 57% in 300 seconds. This activity decreased progressively due to the increase in pH values. In a short incubation period and at high temperature values, the crude laccase enzyme removed the color of the dye at 50 °C (56%), 60 °C (45%), and 70 °C (38%). These data are important for improving methods for decolorization of textile dyes used at high temperatures in various industrial applications. [ABSTRACT FROM AUTHOR]

In this study, a novel immobilization support for laccase was developed to enhance enzyme stability, efficiency and reusability. Firstly, Fe 3 O 4 magnetic particles were synthesized and modified by the co-precipitation route using thiolated chitosan (TCS). The support was characterized using several methods. Afterward, laccase was attached to the surface of functional support. The biochemical properties of the immobilized laccase were comprehensively investigated. It was observed that immobilized laccase achieved maximum activity at pH 4.0 and the optimum temperature was found to be 50 °C. After storage at +4 °C and ~25 °C for 4 weeks, the residual activity of the immobilized laccase was 87% and 80% of its initial activity, respectively. At 55 °C, the activity of immobilized laccase decreased to 73.4% in 180 min and after reused 20 times, the relative activity of immobilized laccase still was approximately 50% of its initial activity. Moreover, the textile dye (Reactive Blue 171 and Acid Blue 74) decolorization activity of immobilized laccase was also tested and it showed long-term textile dye decolorization activity. These results are promising for the use of laccase in industrial and biotechnological applications. Therefore, this functionalized magnetic hybrid composite might be used to immobilize laccase, an industrially important enzyme. • Fe 3 O 4 -TCS hybrid composite was synthesized for laccase immobilization. • Immobilized laccase showed high stability in a wider temperature and pH range. • The immobilized laccase exhibited well reusability after reused 20 times. • In addition, immobilized laccase showed long-term textile dye decolorization activity. [ABSTRACT FROM AUTHOR]