Morphological,biochemical and kinetic properties of lipase from Candida rugosa immobilized in zirconium phosphate |
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Authors: | Adriano A. Mendes Bruno C. M. Barbosa Maria L. C. P. Da Silva |
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Affiliation: | Engineering School of Lorena, University of S?o Paulo, 12.600-970, Lorena, SP, Brazil |
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Abstract: | Zirconium phosphate (ZrP), a low-cost inorganic material with well-defined physicochemical properties, was successfully used as support for immobilizing Candida rugosa lipase by covalent bonding. The immobilized derivative showed high catalytic activity in both aqueous and non-aqueous media. Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy measurements demonstrated that the ZrP fulfilled the morphological requirements for use as a matrix for immobilizing lipases. The free and immobilized lipases were compared in terms of pH, temperature and thermal stability. The immobilized lipase had a higher pH optimum (7.5) and higher optimum temperature (50°C) than the free lipase. Immobilization also increased the thermal stability. The hydrolysis of p-nitrophenyl palmitate (pNPP) by immobilized lipase, examined at 37°C, followed Michaelis–Menten kinetics. Values for Km=1.18 µM and Vmax=325Umg?1 indicated that the immobilized system was subject to mass transfer limitations. The immobilized derivative was also tested under repetitive reaction batches in both ester hydrolysis and synthesis. |
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Keywords: | Lipase immobilization zirconium phosphate covalent bonding |
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