Preparation and Characterization of Chitosan-Coated Manganese-Ferrite Nanoparticles Conjugated with Laccase for Environmental Bioremediation

Azzurra Apriceno; Ilaria Silvestro; Annamaria Girelli; Iolanda Francolini; Loris Pietrelli; Antonella Piozzi

doi:10.3390/polym13091453

Preparation and Characterization of Chitosan-Coated Manganese-Ferrite Nanoparticles Conjugated with Laccase for Environmental Bioremediation

Polymers (Basel). 2021 Apr 30;13(9):1453. doi: 10.3390/polym13091453.

Authors

Azzurra Apriceno^{1

2}, Ilaria Silvestro¹, Annamaria Girelli¹, Iolanda Francolini¹, Loris Pietrelli¹, Antonella Piozzi¹

Affiliations

¹ Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
² Insitute for Bioengineering of Catalonia, Parc Científic de Barcelona (PCB), c/Baldiri Reixac 10-12, 08028 Barcelona, Spain.

Abstract

Bioremediation with immobilized enzymes has several advantages, such as the enhancement of selectivity, activity, and stability of biocatalysts, as well as enzyme reusability. Laccase has proven to be a good candidate for the removal of a wide range of contaminants. In this study, naked or modified MnFe₂O₄ magnetic nanoparticles (MNPs) were used as supports for the immobilization of laccase from Trametes versicolor. To increase enzyme loading and stability, MNPs were coated with chitosan both after the MNP synthesis (MNPs-CS) and during their formation (MNPs-CS_{in situ}). SEM analysis showed different sizes for the two coated systems, 20 nm and 10 nm for MNPs-CS and MNPs-CS_{in situ}, respectively. After covalent immobilization of laccase by glutaraldehyde, the MNPs-CS_{in situ}-lac and MNPs-CS-lac systems showed a good resistance to temperature denaturation and storage stability. The most promising system for use in repeated batches was MNPs-CS_{in situ}-lac, which degraded about 80% of diclofenac compared to 70% of the free enzyme. The obtained results demonstrated that the MnFe₂O₄-CS_{in situ} system could be an excellent candidate for the removal of contaminants.

Keywords: bioremediation; chitosan; diclofenac removal; immobilized enzyme; laccase; magnetic nanoparticles.