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Immobilization of Laccase Using Metal-Organic Framework and its Application in Micropollutant Removal

Ghassemi, Raman | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55330 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Yaghmaei, Soheila; Ghobadinejad, Zahra
  7. Abstract:
  8. Nowadays, micropollutants present in aquatic environments posses a significant threat to the well-being and health of human beings. Various physicochemical and advanced approaches have been proposed to confront these hazards. In recent years, biological treatment methods have gained great interest for their green approach. One of these biological treatment options is the treatment of polluted waters by enzymes. Enzymatic treatment of micropollutants can be achieved by oxidoreductase enzymes. One of the most important and widely used oxidoreductase enzymes employed for water treatment is Laccase. However, enzyme immobilization is employed to counter the drawbacks of using enzymes, such as lack of recyclability and low operational stability. Thus, in this project, laccase from Trametes sp. is immobilized using metal-organic frameworks (MOFs), a novel group of porous compounds. Then the immobilized enzyme is characterized and used to eliminate an endocrine-disrupting chemical, Bisphenol A. Laccases were immobilized in 3 approaches in different MOFs. At first, Commercial laccase from Trametes hirsuta was encapsulated inside ZIF-8. The biocatalyst showed an activity recovery of 142%. However, the encapsulated enzyme was not applicable for pollutant elimination. Then, the previously synthesized ZIF-8 structure was aminated by APTES and further modified with glutaraldehyde. Then the Trametes hirsuta enzyme was covalently attached to the modified MOF. This approach showed an activity recovery of only 4%. Finally, the produced Trametes sp. enzyme was immobilized using a zinc-based aminated MOF (IRMOF-3). The immobilized enzyme achieved an activity recovery of 64%. This biocatalyst was chosen for further characterization parts of the project. Furthermore, the biocatalyst was used to eliminate Bisphenol A, an Endocrine-disrupting chemical. The hybrid structure removed 91.5% of the pollutant in 12 hours. The Enzyme was responsible for 67.2% of the elimination through biodegradation pathways. The remaining 32.8% of Bisphenol A removal is attributed to the physical adsorption of pollutants into the porous support MOF.

  9. Keywords:
  10. Laccas Enzyme ; Bisphenol A ; Micropollutants ; Biodegradation ; Enzyme Stabilization ; Laccas Imobilization ; Metal-Organic Framework ; Trametes Hirsuta Mold

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