Study On The Preparation Of Laccase@HP-MOFs And Its Degradation Of Antibiotics

This paper starts from the advantages and wide application of the immobilized enzymes of MOFs materials,and aims at the problems of free laccase being easily affected by the external environment and poor reusability.The HP-MOF material HcP-UiO-66-NH₂（30）was used as the immobilized carrier to successfully prepare an immobilized enzyme（Lac@HcP-UiO-66-NH₂（30））with better enzymatic properties than free laccase.At the same time,it was applied to the field of antibiotic pollution control,and successfully achieved the complete degradation of lincomycin hydrochloride and rifampicin.The good recyclability of the immobilized laccase also provided reference for the practical application of laccase in the field of environmental remediation.The specific research contents are as follows:（1）Preparation and performance study of immobilized laccase on HP-MOFs:Based on the wide substrate specificity of laccase and the high stability of MOFs,the immobilized laccase Lac@HcP-UiO-66-NH₂（30）with excellent performance was synthesized by one-step adsorption method.When the molar ratio of modifier dodecanoic acid to zirconium X=30,the synthesized material HcP-UiO-66-NH₂（30）has the largest porosity and a mesoporous structure larger than the diameter of the laccase（7.6 nm）.This structure increased the loading rate of laccase.The optimal immobilization conditions obtained by process optimization were:the optimal adsorption time was 2h,and when the addition amount of Lac was 300 mg/g,the solid load of Lac@HcP-UiO-66-NH₂（30）was the largest,reaching 275.96 mg/g.When the addition amount of Lac was 150 mg/g,the activity recovery rate of Lac@HcP-UiO-66-NH₂（30）was the highest,reaching 618%.After characterization of the morphology and structure,MOFs showed octahedral structure,and Lac@HcP-UiO-66-NH₂（30）has been successfully loaded with Lac.Finally,the enzymatic properties of Lac@HcP-UiO-66-NH₂（30）were explored.It has better stability and higher enzyme catalytic efficiency than free Lac,which provides the possibility for the industrial application of laccase.（2）Studies on the Biodegradation and catalytic mechanism of antibiotics degradation by Lac@HcP-UiO-66-NH₂（30）:Based on the strong stability and high activity of the immobilized laccase Lac@HcP-UiO-66-NH₂（30）,it was applied to the biodegradation of lincomycin hydrochloride and rifampicin.In the Lac@HcP-UiO-66-NH₂（30）-TEMPO catalytic system,at 30℃,200 rpm,100 mg/L lincomycin hydrochloride was completely degraded within 6 hours,100 mg/L rifampicin was completely degraded within 6 minutes.When the Lac@HcP-UiO-66-NH₂（30）was continuously recycled for 8 times,the degradation efficiency of the two antibiotics was still more than 75%,and the reusability was good.It has been verified that the degradation products of the two antibiotics have weakened antibacterial effect to Bacillus subtilis.It can be seen that Lac@HcP-UiO-66-NH₂（30）has excellent characteristics that make it an ideal biocatalyst for environmental remediation.