An antibiotic-destructase-activated Fenton-like catalyst for synergistic removal of tetracycline residues from aquatic environment

Environmental tetracycline (TC) residues are deemed as persistent contamination that threats to public health, underlining the necessity for innovative remediation technologies. Herein, TET(X), a TC destructase we identified previously, was found to produce H₂O₂ during degrading TC. Therefore, a Cu-based metal − organic framework (Cu-MOF) was incorporated with TET(X) to catalyze the Fenton-like reaction in response to TET(X)-produced H₂O₂, which eminently promoted non-enzymatic breakdown of TC. The designed composite (TET(X)-MOF) was functionally characterized to produce reactive radicals in presence of TC and be able to eradicate 50 ppm TC rapidly in a synergistic manner. The response surface method identified environmental pH as critical factor to TET(X)-MOF efficiency, suggesting that enzymatic activity of TET(X) controlled the degradation catalysis. To verify the in situ efficiency, the TET(X)-MOF was utilized to remove the TC from various environmental matrices including pond water, livestock sewage, urine and pharmaceutic effluent. High efficiency of the composite was observed as 47.9 %-100 % TC was eliminated in matrices within 3 h. Moreover, the degradation pathways of TC were proposed according to the intermediates. Eventually, the in vivo toxicity assessment indicated that the TET(X)-MOF enjoys desirable biosafety without further introduction of hazardous substance. Overall, this is the first study reporting the Fenton-like catalyst activated by and synergistically collaborated with antibiotic destructase for antibiotic decontamination. Such composite, as concept-of-principle, is of great potential to eradicate TC residues and opens up novel perspectives to develop strategies for environmental remediation.