Surface and stability analysis of immobilized laccase on poly(ethylene terephthalate) grafted maleic anhydride nanofiber mat

Abstract

BACKGROUND A poly(ethylene terephthalate) (PET) based carrier was used for enzyme immobilization due to its good physical and mechanical properties. However, its high hydrophobicity and chemically inactive properties hindered its capability as an enzyme carrier. This study developed a PET-based carrier by grafting PET with maleic anhydride (MAH) before electrospinning. This carrier was used to immobilize laccase and characterized based on its stability after immobilization. RESULTS The highest laccase activity recovery for laccase immobilized on PET-g-MAH nanofiber mat was 59.17% using covalent bonding, followed by the crosslinking method. The static water contact angle of PET-g-MAH nanofiber mats was reduced from 129 +/- 8(o) to 109 +/- 12(o). Based on the Wenzel model, the reduction was due to the decrease in surface roughness of the hydrophobic surface. Besides, the immobilized laccase also withstood high temperature up to 60 degrees C and retained about 29.22% +/- 5.06% of its initial activity after 30 days of storage and repeated use. CONCLUSION Laccase immobilization on PET-g-MAH nanofiber has good stability (thermal, storage and reusability) and is recommended to be implemented in the industries.