ABSTRACT
Horseradish peroxidase (HRP) holds great potential in wastewater treatment. However, its instability in harsh environments remains a major issue. Various immobilization technologies were developed to retain enzyme stability at the cost of its effectiveness. We demonstrate that zwitterionic encapsulation of HRP retained both protein stability and activity to a large degree. In a water treatment study, encapsulating HRP into a zwitterionic nanogel resulted in a three-fold increase in the catalytic oxidation efficiency of phenol molecules. In addition, zwitterionic nanocapsules exhibited the best performance when compared with nanocapsules made from other hydrophilic polymers. These results indicated that zwitterionic HRP nanocapsules hold great potential in the decontamination of organic pollutants from wastewater.
Subject(s)
Horseradish Peroxidase/chemistry , Nanogels/chemistry , Phenol/chemistry , Wastewater/chemistry , Water Pollutants, Chemical/chemistry , Acrylamides/chemical synthesis , Acrylamides/chemistry , Armoracia/enzymology , Enzyme Stability , Hydrogen Peroxide/chemistry , Oxidation-Reduction , Polymers/chemical synthesis , Polymers/chemistry , Water Purification/methodsABSTRACT
As ubiquitous environmental pollutants, phenolic compounds are requested to be efficiently removed from wastewater. Enzymes, such as Horseradish peroxidase (HRP), have been demonstrated with great potential in removing phenolic compounds. Different from the general immobilization technology, the encapsulation of individual enzymes within nanogel has been employed in this work. Here we show that, the encapsulated HRP could remarkably enhance enzymatic performance, including thermostability, catalytic efficiency, environmental tolerance and, most importantly, the biodegradation of phenolic compounds. For instance, the removal efficiencies of phenol and BPA increased by 7-fold and 3.5-fold, respectively. On the other hand, the diverted removal efficiencies were obtained for a series of phenolic compounds. Based on molecular modelling, the biodegradabilities of phenolic compounds were rationalized according to their redox potentials and binding affinities with enzymes. In summary, our work indicates that the nanocapsulation of enzyme should be a promising strategy in removing different types of phenolic compounds from wastewater.