Development and Application of a Hybrid Support of Laccase from Trametes versicolor with Zinc Oxide Nanoparticles for Textile Dye Degradation

TL;DR

Researchers created a hybrid support using laccase and zinc oxide nanoparticles to efficiently degrade textile dyes, showing improved stability and performance.

Contribution

A novel hybrid support combining laccase with green-synthesized ZnO nanoparticles for enhanced dye degradation.

Findings

The hybrid support with ZnO nanoparticles showed 153% initial enzyme activity after 35 days, compared to 68% without ZnO.

The immobilized biocatalyst achieved 86% degradation of Reactive Blue 198 under optimized conditions.

Cu2+ provided the highest immobilization efficiency (52%) with reduced enzyme leakage.

Abstract

A hybrid support based on sodium alginate and green-synthesized
ZnO nanoparticles was developed for the immobilization of laccase
(Trametes versicolor) and applied to
textile dye degradation. ZnO nanoparticles were biosynthesized using
pecan shell (Carya illinoinensis) extract
in combination with a zing precursor salt (Zn­(NO3)2·6H2O) and characterized by ultraviolet–visible
(UV–Vis) absorption spectroscopy, Fourier transform infrared
spectroscopy with attenuated total reflectance (FTIR–AR), scanning
electron microscopy (SEM), and energy-dispersive X-ray spectroscopy
(EDS), confirming their structural and morphological features. Laccase
was entrapped in sodium alginate beads and cross-linked with divalent
cations (0.2 M CaCl2, BaCl2 or CuSO4) supplemented with glutaraldehyde (100 μL of 50% v/v) during
bead formation; beads were kept in the cross-linking solution for
60 min, washed and stored at 4 °C. Immobilized systems were evaluated
for immobilization yield, efficiency, enzyme leakage, and storage
stability. Among the tested agents, Cu2+ provided the highest
immobilization efficiency (52%) with reduced enzyme leakage. The hybrid
support containing ZnO nanoparticles (Alg + ZnO-NPs@Lac) exhibited
remarkable improvements in enzyme stability, maintaining 153% of its
initial activity after 35 days, compared to only 68% for alginate
without ZnO. The immobilized biocatalyst demonstrated enhanced tolerance
to pH and temperature variations and achieved up to 86% degradation
of Reactive Blue 198 under optimized conditions. These findings highlight
the synergistic effect of ZnO nanoparticles in strengthening the mechanical
and thermal resistance of the alginate matrix and improving laccase
stability, offering a sustainable and efficient platform for the enzymatic
treatment of textile dyes and emerging micropollutants in wastewater.

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