Laccase, the blue oxidase enzyme with high potency in green synthesis and biodegradation of phenolic
compounds, was immobilized by means of chitosan nanoparticles (CS-NPs) on the surface of activated
glass beads. Decolorization of Congo red, a harmful industrial dye, was accomplished with
nanoparticulated immobilized laccase, directly attaching enzyme on the surface of the glass beads,
as well as the free enzyme in order to assess the decolorization activity of immobilized and nonimmobilized
laccase. Glass surface functionalization was achieved by using chemicals such as sodium
hydroxide, 3-aminopropyltriethoxysilane (APES), and glutaraldehyde. Dynamic light scattering (DLS)
and scanning electron microscopy (SEM) were used for characterizing enzyme-associated CS-NPs, made
by the ion gelation method. Fourier Transform Infrared Spectroscopy (FT-IR) was carried out to identify
the attached chemical groups on the surface of the glass beads. Immobilization yields for
nanoparticulated and non-nanoparticulated enzymes were 75 4.2 and 68.6 6.4%, respectively
whereas, immobilization efficiency for nanoparticulated and non-nanoparticulated laccases were calculated
as 40.1 3.4 and 32.2 7.5%, respectively. The applied method for immobilization resulted in increased
thermal stability, reusability, and lifetime of the enzyme. Thermal stability of the nanoparticulated
immobilized enzyme increased up to near boiling temperature. In addition, 98% of initial decolorization
activity of the nanoparticulated immobilized enzyme was retained after 25 successive cycles.