Laccase Immobilization on Tannic Acid–Coated Nylon Membrane for Dye Decolorization

Abstract

Laccase catalyzes the oxidation of a wide array of substrates, yet its industrial applications are hindered by its low thermal and chemical stability, poor reusability, and high production costs. Enzyme immobilization is a cost-effective strategy for overcoming these limitations, enhancing stability and operational efficiency. In this study, laccase from Trametes versicolor (LTV) was immobilized onto a nylon membrane coated with 3-aminopropyltriethoxysilane (APTES) and tannic acid (TA). A mathematical model was employed to optimize enzyme immobilization parameters (e.g., pH, LTV concentration, TA:APTES ratio, and reaction time), resulting in an enzyme loading of 31.9% w/w LTV and immobilization yield of 67.3%. The resulting biocatalytic system was characterized via ATR-FTIR, SEM–EDX, Raman, and fluorescence techniques, and the kinetics of free and immobilized LTV were analyzed. Immobilized LTV successfully oxidized 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) across broad pH (2–9) and temperature (20 °C–70 °C) ranges. Compared to the free enzyme, immobilized LTV demonstrated improved storage stability and catalytic performance. Notably, immobilized LTV successfully decolorized methylene blue and methyl red dyes, validating the utility of this platform for environmental remediation applications.