Highly efficient direct oxygen electro-reduction by partially unfolded laccases immobilized on waste-derived magnetically separable nanoparticles.

A biocatalytic system based on laccase functionalized waste-derived iron oxide nanoparticles (LAC-DA-Fe2O3) was designed by a mechanochemical approach and employed in the electrocatalytic reduction of oxygen. Full characterization of the obtained bioconjugates revealed that the protein adopted a partially unfolded state. The mentioned configuration, together with the geometry coordination changes along the T1 center can be further related to a high bioelectrocatalytic response. A current density up to 2.9 mA cm-2 has been achieved, which is among the highest values reported in literature for laccase functionalized nanomaterials.