Fabrication of cellulose acetate/chitosan/poly(ethylene oxide) scaffold as an efficient surface area substrate for immobilization of laccase

Abstract

In this study, the properties of the immobilized laccase process on cellulose acetate (CA)/chitosan (CHI)/poly (ethylene oxide) (PEO) electrospun nanofiber was studied. Trametes versicolor laccase's immobilization on the porous electrospun nanofibers (ENFs) with 89–119 nm diameter by polyethyleneimine (PEI) and glutaraldehyde covalent cross-linking was also investigated. Blending CA nanofibers with high hydroxyl (OH) groups and CHI with high reactive hydroxyl and amino functional groups leads to a strong affinity for various proteins and outstanding mechanical properties. In Fourier-transform infrared spectroscopy (FT-IR) spectra, the vibrations at 1560 and 1640 cm−1 about NH stretching indicated that laccase was immobilized on ENFs. Differential scanning calorimetry (DSC) demonstrated that the thermal stability of CA/CHI/PEO improved with immobilization. The laccase loaded on the membranes was around 803 mg/g at pH 5.5, and the immobilized laccase relative activity was about 76.32%. The oxidation of ABTS determined the performance of immobilized and free laccases. Compared with free laccase, the pH and thermal stability of the immobilized laccase were remarkably improved. Over 50% of the immobilized laccase life was maintained for up to 5 cycles and had greater than 75.8% of initial activity and 64.87% of optimum activity. The immobilized laccase on CA/CHI/PEO ENFs with fine diameters enhanced the loading of the enzyme. Hence, immobilized laccase might be an ideal candidate for industry usage instead of free enzymes.

Keywords

• Electrospinning
• Enzyme immobilization
• Laccase
• Nanofiber
• Morphology