Enzymatic degradation of harmful micropollutants using laccase is currently one of the most studied alternatives to face the continuous accumulation of these compounds in natural water. More specifically, laccase-coated membranes offer the advantage of continuous operability, compatible with water treatment processes. In this work, laccase is immobilized within nanoporous polycarbonate membranes using the layer-by-layer (LbL) assembly approach. The impact of different parameters on the build-up of polyelectrolyte-enzyme multilayers is firstly investigated on flat surfaces. This study reveals that the optimal build-up strategy consists in selecting polyethyleneimine as polycation, using MES buffer as the assembly medium and performing a cross-linking after each bilayer deposition. Under these conditions, very active (enzymatic activity of 1.3 mU. cm-2) and stable (79% of the activity is maintained after the 5th catalytic cycle) coatings are obtained. Polycarbonate membranes coated with this strategy achieve a capacity up to 55 µmol.min-1.cm-2 of oxidized ABTS when operated in a flow reactor, and remain stable after 45 days of storage. Overall, this work provides insight into the mechanisms underlying LbL assembly and crosslinking of laccase-containing films and, demonstrates the potential of laccase-coated membranes as efficient and stable materials for use in flow reactors.
