Silica-chitosan hybrid support for laccase immobilization.

The aim of this study was to optimize the laccase immobilization on a silica/chitosan composite support. The innovative method proposed is based on the use of Ca(II) as a linker of the support precursors. In addition for the laccase immobilization the glycosidic part of enzyme is oxidized by periodate in order to form aldehydes reactive towards the NH2 groups of chitosan. The immobilized laccase presents a good storage stability (7 months 40% residual activity) and a good affinity towards ABTS substrate (Kmapp 0.008 mM, Vmaxapp = 0.0034 μmol/min). Furthermore, the biocatalyst showed optimum pH 3 and optimum incubation temperature of 50 °C.