Development of dual-enhancer biocatalyst with photothermal property for the degradation of cephalosporin

The abuse of cephalosporins poses a serious threat to human health and the ecological environment. In this work, cephalosporinase (AmpC enzyme) and Prussian blue (PB) crystals were encapsulated into ZIF-8 metal-organic frameworks (MOFs), and a photothermal AmpC/PB@ZIF-8 MOFs (APZ) nanocatalyst was prepared for the catalytic degradation of cephalosporin. The temperature of the APZ catalytic degradation system can be regulated by irradiation with near infrared light due to the photothermal effect of PB, and then, the activity of the APZ biocatalyst is significantly enhanced. Thereby, the degradation efficiency of cefuroxime can reach to 96%, and the degradation kinetic rate of cefuroxime augmented 4.5-fold comparing with that catalyzed by free enzyme. Moreover, encapsulation of the enzyme and PB can increase the affinity and charge transfer efficiency between APZ and substrate molecules, which can also improve the degradation efficiency of cephalosporins. Catalytic degradation pathways for three generations of cephalosporins were proposed based on their degradation products. The dual-enhancer biocatalyst based on the photothermal effect and immobilization of the PB and enzyme can significantly enhance the activity and stability of the enzyme, and it can also be recycled. Therefore, the biocatalyst has potential applications for the effective degradation of cephalosporins in the environment.