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Studying Immobilization of Laccase by Entrapment and Its Applications in Micropollutants Removal from Aqueous Wastewater

Toutounchi, Arvin | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55165 (06)
  4. University: Sharif University of Technolog
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Yaghmaei, Soheila; Ghabodinejad, Zahra
  7. Abstract:
  8. One of the major environmental problems in recent years is the presence of micropollutants that cause many problems for the environment and living organisms. The micropollutant bisphenol A and the drug diclofenac are one of the pollutants and endocrine disruptors. Usually, conventional biological and physico-chemical methods do not have a high ability to remove such pollutants. Also, advanced oxidation methods usually lead to the production of highly toxic products. Using enzymes is an attractive method to remove these micropollutants. Laccase enzyme is one of the most famous enzymes in the field of biotherapy because it can remove a wider range of pollutants and it is one of the oxidoreductase enzymes. In this research, laccase enzyme was produced from white mold Trametes sp. The produced laccase enzyme was first cross-linked with glutaraldehyde for stability and reusability, and then it was stabilized inside calcium alginate polymer beads using encapsulation method. Cross-linking laccase enzyme before entrapment reduced enzyme leakage by 4-fold and increased activity recovery in the fixation process by 1.4-fold. Finally, the stabilized enzyme was investigated to remove bisphenol A and diclofenac under optimal conditions (i.e. pH=5, temperature 30 °C, concentration 25 ppm and enzyme activity 10 U/mL). The amount of removal of bisphenol A and diclofenac by the stabilized enzyme was more than 97% in 5 and 6 hours, respectively. The kinetic parameters Km and Vmax for the stabilized enzyme were measured as 0.172 mM and 0.256 mM/min, respectively. Also, the structure of the stabilized enzyme was analyzed using a scanning electron microscope, the stability of the stabilized enzyme and the reusability of the stabilized enzyme were analyzed.
  9. Keywords:
  10. Bisphenol A ; Laccas Enzyme ; Enzyme Stabilization ; Sequestration ; Trametes Mpecies Mold ; Diclofenac Sodium ; Micropollutants

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