Preparation and characterization of laccases immobilized on magnetic nanoparticles and their application as a recyclable nanobiocatalyst for the aerobic oxidation of alcohols in the presence of TEMPO

Laccase from Trametes versicolor was immobilized on a modified magnetic nanoparticle (MNP-Laccase) through a covalent attachment method. The morphology, structure, magnetic property and chemical composition of the immobilized laccase (MNP-Laccase) were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), alternating gradient force magnetometry (AGFM), energy-dispersive X-ray spectroscopy (EDX) and thermogravimetric analysis (TGA) techniques. The MNPs-Laccase retained the activity and exhibited higher resistance to pH and temperature changes. We have used MNPs-Laccase as a magnetically recoverable nanobiocatalyst for the mild, environmentally friendly and selective aerobic oxidation of benzylic and allylic alcohols to corresponding aldehydes in the presence of TEMPO as a redox mediator at room temperature. The magnetic nanobiocatalyst was easily and rapidly recovered by applying an external magnet device and reused up to 6 reaction runs without considerable loss of reactivity. MNPs-Laccase as a novel magnetically recyclable nanobiocatalyst has been used for the selective aerobic oxidation of alcohols.