Catalytic, Kinetic, and Thermodynamic Properties of Pleurotus Ostreatus NRRL 3501 Laccase Immobilized on Clinoptilolite Nanoparticles and its Application in Dye Decolorization

Document Type : Original Article

Authors

1 Chemistry of Natural and Microbial products Department, National Research Centre, Dokki, Giza, Egypt.

2 Refractories, Ceramics and Building Materials Department, National Research Centre, Dokki, Giza, Egypt.

3 Dyeing, Printing and Textile Auxiliaries Department, National Research Centre, Dokki, Giza, Egypt.

Abstract

Laccase from Pleurotus ostreatus was immobilized on different nanoparticles by physical adsorption and covalent binding. The immobilized enzyme on Na-clinoptilolite nanoparticles showed the highest recovered activity (71.75%) and thermal stability. X-Ray diffraction, surface morphology and the internal structure of the immobilization carrier (Na-clinoptilolite nanoparticles) were investigated. Compared to the free enzyme, the immobilized preparation exhibited higher optimum temperature, lower activation energy (Ea), lower deactivation constant rate (kd), higher t1/2 and higher decimal reduction time values (D) within the temperature range of 50–70◦C. The thermodynamic parameters (ΔH*, ΔG*, ΔS*) of irreversible thermal denaturation for the free and immobilized laccase were also evaluated. The values of enthalpy of activation (ΔH*), and free energy of transition state binding (ΔG*E−T) for substrate catalysis were lowered for the immobilized enzyme. Moreover, there was highly significant impact on improving the values of Vmax/Km, kcat, kcat/Km, and ΔG*E−S for the immobilized enzyme. The immobilized laccase from Pleurotus ostreatus NRRL 3501 on Na-clinoptilolite nanoparticles was evaluated for dye decolorization. In batch experiments the immobilized enzyme was able to decolorize the following dyes R. Blue 203 (97%), A. red 299 (100%), and Acid mix (89%) after incubation for 120 min. In repeated use the immobilized enzyme was able to decolorize the dye for 8 continuous cycles.

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Egyptian Journal of Chemistry
Volume 67, Issue 13 - Serial Number 13
In Loving Memory of Late Professor Doctor ””Mohamed Refaat Hussein Mahran””
December 2024
Pages 461-469

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History

  • Receive Date: 24 December 2023
  • Revise Date: 11 January 2024
  • Accept Date: 28 January 2024

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