A recyclable UCST-type biocatalyst to catalyze H2O2 degradation of phenol

Horseradish peroxidase (HRP) is a kind of enzyme commonly used in clinical trials that is rich in the plant horseradish. It has a wide range of applications in the fields of pharmacy and pollution control . However, free enzymes are easily denatured and inactivated by environmental influences, which is not conducive to the normal progress of the reaction. At the same time, the cost of enzymes is relatively high, and it is difficult to separate and recover during the reaction. In this study, the UCST-type temperature- responsive polymer was combined with HRP under the optimal immobilization reaction conditions of 3% polymer solution concentration, 60 ℃, and pH= 8 through affinity interaction to produce UCST-type smart polymerase. The smart polymerase has stronger temperature stability, pH stability and storage stability than free enzymes. In the simulated pollutant degradation experiment, under the molar ratio of phenol to H 2 O 2 is 1:1, the temperature of 60 ℃, and pH= 7, smart polymerase can degrade 91% of phenol in a 100 mg/L phenol solution within 1 h. After five cycles of catalytic reaction , 68% of smart polymerase was recovered through cooling precipitation. In the phenol degradation experiments of two different real water samples, 88% and 90% of the phenol in the water were removed, respectively, and most of the highly active immobilized enzymes were recovered at the same time. Finally, the biotoxicity of the catalyzed reaction product is significantly reduced was demonstrated.