Design of bioreactor based on immobilized laccase on silica-chitosan support for phenol removal in continuous mode

•Immobilized enzyme reactor for phenol removal in continuous mode.•Covalent immobilization of oxidized laccase on silica-chitosan hybrid support.•IMER retained 70 % activity for 70 days and after 300 injections.•High removal efficiency (∼90 %) for phenols mixture by immobilized laccase reactor. A silica-chitosan support was employed for laccase immobilization. The hybrid support was obtained using calcium ion as linking agent that coordinates silanol and hydroxyl groups of chitosan. The insoluble biocatalyst was then packed in a column and used in a flow system for phenol removal. The immobilized enzyme reactor (IMER) showed a good storage stability (70 % of activity in 70 days) and good reusability (90−50 % of catalytic activity at the 4th reuse in function of chitosan type). The best performance for the phenol removal was obtained with a low molecular weight chitosan from crab shells at pH 5 and with a flow rate of 0.7 mL/min. The apparent Michaelis–Menten (Vmaxapp, Kmapp) and the inherent (Vmaxinh, Kminh) constants were also determined to evaluate the influence of the phenol structure on the performance of the system. The enzymatic oxidation of a phenol mixture (4-methylcatechol, catechol, caffeic acid, syringic acid, vanillic acid, p-coumaric acid, and tyrosol) was followed for 21 h in a continuous mode by HPLC. The phenol mixture removal of 90 % was also confirmed by Folin‐Ciocalteu assay.