Silica-chitosan hybrid support for laccase immobilization

Area of Science:

• Biotechnology
• Biocatalysis
• Materials Science

Background:

• Enzyme immobilization is crucial for biocatalyst stability and reusability.
• Silica/chitosan composites offer promising support materials due to their properties.
• Laccase enzymes have broad industrial applications but require efficient immobilization strategies.

Purpose of the Study:

• To optimize the immobilization of laccase onto a silica/chitosan composite support.
• To develop an innovative immobilization method using calcium(II) and periodate oxidation.
• To characterize the stability, affinity, and optimal conditions of the immobilized laccase.

Main Methods:

• Utilized calcium(II) as a linker for silica/chitosan precursor assembly.
• Oxidized the glycosidic moiety of laccase with periodate to create reactive aldehydes.
• Immobilized the modified laccase onto the composite support via reaction with chitosan's amine groups.

Main Results:

• Achieved good storage stability with 40% residual activity after 7 months.
• Demonstrated high affinity for ABTS substrate with apparent Michaelis constant (K_m^app) of 0.008 mM and apparent maximum velocity (V_max^app) of 0.0034 μmol/min.
• Determined optimal operational conditions: pH 3 and incubation temperature of 50°C.

Conclusions:

• The developed immobilization method enhances laccase stability and performance.
• The silica/chitosan composite support provides an effective matrix for laccase immobilization.
• The optimized biocatalyst is suitable for applications requiring stable and active laccase under specific conditions.