Horseradish peroxidase (HRP) was immobilized on Eupergit® C 250 L coated with polyelectrolytes, or by entrapment inside pre-formed layer by layer (LbL) microcapsules of polyelectrolytes. In these systems, namely HRP/E-LbL, HRPm/LbL and HRPm/LbLp, the native enzyme retained its catalytic activity. Immobilized HRP showed a significant activity in the oxidation of selected azo, quinoline and fluorone dyes with H2O2 as primary oxidant under mild experimental conditions, HRPm/LbL being the best catalyst. The comparison between the catalytic efficiency of different redox mediators for HRP activity was made using 1-hydroxybenzotriazole (HOBt), violuric acid (VLA) and veratrylic alcohol (VA). As a general trend, azo dyes were degraded with higher yields, HOBt being the best mediator for the oxidation. The degradation yield increased by increasing the reaction time, reaching the highest value after 12 hours, comparable with that observed for the native HRP. Noteworthy, HRPm/LbL retained its catalytic activity for more runs.

Dye Degradation by Layer-by-Layer Immobilised Peroxidase/Redox Mediator Systems

CRUCIANELLI, MARCELLO
2013

Abstract

Horseradish peroxidase (HRP) was immobilized on Eupergit® C 250 L coated with polyelectrolytes, or by entrapment inside pre-formed layer by layer (LbL) microcapsules of polyelectrolytes. In these systems, namely HRP/E-LbL, HRPm/LbL and HRPm/LbLp, the native enzyme retained its catalytic activity. Immobilized HRP showed a significant activity in the oxidation of selected azo, quinoline and fluorone dyes with H2O2 as primary oxidant under mild experimental conditions, HRPm/LbL being the best catalyst. The comparison between the catalytic efficiency of different redox mediators for HRP activity was made using 1-hydroxybenzotriazole (HOBt), violuric acid (VLA) and veratrylic alcohol (VA). As a general trend, azo dyes were degraded with higher yields, HOBt being the best mediator for the oxidation. The degradation yield increased by increasing the reaction time, reaching the highest value after 12 hours, comparable with that observed for the native HRP. Noteworthy, HRPm/LbL retained its catalytic activity for more runs.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/16812
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