Phenols removal by immobilized tyrosinase reactor in on-line high performance liquid chromatography

The development of an immobilized enzyme reactor (IMER) based on tyrosinase immobilized on aminopropyl-controlled pore glass (AP-CPG) for the removal of phenols from model aqueous solutions was reported. To elucidate the influence of the substrate nature, the apparent (V′maxV′max, K′mK′m) and the inherent (Vmax, Km) Michaelis–Menten constants were determined by Lineweaver–Burk method and the external diffusional contributions on measured enzyme activities were removed by a graphical method. The dephenolization process was realized by recycling the phenol solutions through the bioreactor connected to a chitosan trap in order to remove the colored quinone-type products of the tyrosinase reactions. The results indicated that a complete removal of phenol derivatives in the range of 150–300 min, with the exception of 60% removal for phenol reached in 400 min, was obtained. The observed sequence: cresol > 4-methylcathecol > catechol > 4-Cl-phenol ≫ phenol was in accordance to the V′maxV′max/K′mK′m values.