Laccase immobilized on chitosan-coated Fe3O4 nanoparticles as reusable biocatalyst for degradation of chlorophenol

Abstract

The enzyme immobilization technology could enhance the overall stability and recover-ability of enzyme, which will promote the enzyme’s further application in more fields. Compared to most complex and cumbersome process of enzyme immobilization, we present a simple, mild and effective strategy to immobilize laccase on magnetic carrier and further applied in degradation chlorophenol. The Fe3O4@CS (Fe3O4@Chitosan) composite nanoparticles as enzyme carrier were prepared by self-assembly method. Laccase was successfully immobilized on Fe3O4@CS composite nanoparticles through covalent bonding and effectively remove chlorophenol from water. The specific activity of IM-laccase (immobilized laccase) reaches 112.4 U and the activity recovery is 51.8%. The storage stability, operational stability, pH stability and thermostability were all improved compare free laccase. The 2,4-DCP (2,4-Dichloro-Phenol) and 4-CP (Chloro-Phenol) were degraded by IM-laccase to test the degradation efficiency and the results showed that the degradation rate to 2,4-DCP and 4-CP reached 91.4% and 75.5% after 12 h. In test of reusability, IM-laccase showed excellent performance that the degradation rate retained 75.8% and 57.4% after 10 cycles of degradation.