Resumen de Tyrosinase Immobilization in Nickel-Cross-Linked Gellan Microspheres and Conversion of l-DOPA to Dopachrome

Diana Gomes, Ângela Sousa, Luís A. Passarinha

• Enzymes are widely applied in different industries, like pharmaceutical, food, biofuel, and waste valorization. However, the enzyme operating conditions are very limited. So, in most industrial processes, enzymes are not efficient, due to the use of harsh conditions, like organic solvents, extreme pH, and temperature. Immobilization arises as a way to overcome the process restrictions by offering better stability, activity, and improved recovery of enzymes. Physical adsorption into a solid support is a simple method to achieve enzyme immobilization and is compatible with different materials, like gellan gum. Tyrosinase is an essential enzyme for the biosynthesis of melanin, flavonoids, and l-DOPA, which is a drug used by the pharmaceutical industry to treat Parkinson’s disease. Therefore, it is important to develop an easy and simple method for tyrosinase immobilization that will allow high efficiency and reusability, making the melanin biosynthesis more cost-effective. In the laboratory experiment of the enzymatic biotechnology class, nickel-cross-linked gellan microspheres were prepared and characterized by the students and used as a solid support for tyrosinase immobilization. The reaction catalyzed by tyrosinase was detected by visual observation. This experiment allows students in the biotechnology field to understand the importance of the immobilization process in catalysis since the industry is exploring environmentally friendly processes and also the impact on enzyme efficiency when catalyzing a reaction. Moreover, it helps the students to acquire laboratory handling in the preparation of immobilized systems, while developing their creativity and innovative ability to overcome problems in the enzymatic biotechnology field.