Immobilization of laccase onto sodium alginate beads activated with glutaraldehyde

Abstract

The principles of green chemistry encourage simple and eco-friendly approaches, using various enzymes for different industries, such as fine chemicals productions and water treatments. To increase operational stability of enzymes, different immobilization techniques must be employed in preparation of highly active biocatalysts. Entrapment of enzymes within a polymer matrix is the simplest immobilization method. Properties, such as size of beads, porosity, enzyme leakage degree, and stability are optimized through alginate and calcium concentrations and the use of cross-linking agents. Alginate beads were prepared in calcium chloride and later on activated using cross-linking agent glutaraldehyde (GA), where GA concentration and time of activation were optimized. Such GA-activated alginate beads were further immobilized with laccase, where the time of immobilization was optimized. Immobilization efficiency and residual activity were determined after optimization protocol, resulting in 97 % and 88 %, respectively. Results indicate that laccase can be immobilized onto alginate beads and their residual activity can be improved by varying the GA concentration for beads’ activation. Such GA-activated alginate beads can be successfully used for laccase immobilization for further applications.