Immobilised peroxidases from Asparagus acutifolius L. seeds for olive mill waste water treatment

Abstract

This work compares the main enzymatic parameters of a cationic peroxidase (AaP-1-4), purified and characterized from Asparagus acutifolius L. seeds (Mol. Biotechnol., 2014, 56, 738–746) and its immobilised form (Eup-AaP-1-4), on Eupergit® CM with Horseradish peroxidase. The optimum in the pH-activity profile was pH 4.0 and pH 3.0 for AaP-1-4 and Eup-AaP-1-4, respectively. Ca²⁺ cation enhanced both enzymatic activities, however, when submitted to a temperature stress (120 min at 50 °C) Eup-AaP-1-4 lost only 20% activity while AaP-1-4 70%. Furthermore, AaP-1-4 was proved to be able to remove (poly)phenols in olive mill waste water (OMW), with hydrogen peroxide electron donor. The Eup-AaP-1-4 kinetic proprieties were investigated and the operational stability evaluated in a continuous stirred membrane bioreactor. AaP-1-4 appears to be a novel non-expensive source of peroxidases suitable for biotechnological applications in the environmental field for the removal of aqueous (poly)phenols produced from several industrial processes.