Preparation of poly (glycidylmethacrylate-methylmethacrylate) magnetic beads: Application in lipase immobilization
Yükleniyor...
Tarih
2008
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Bv
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Magnetic bead was prepared from the monomers glycidylmethacrylate (GMA) and methylmethacrylate (MMA) via suspension copolymerization in the presence of ferric ions. The magnetic beads were characterized with scanning electron microscope (SEM), FT-IR and ESR spectrophotometers. The beads were sieved and 100-150 mu m size of fraction was used in enzyme immobilization. The specific surface area of the magnetic beads was measured by the BET method and was found to be 16.2 m(2)/g beads. The reactive character of the epoxy groups allowed the attachment of the amino groups during thermal precipitation reaction. The resulting magnetic beads were used for the covalent immobilization of Candida rugosa lipase via glutaraldehyde activation and glutaraldehyde was also acted a 5-carbon spacer arm. The maximum lipase immobilization on magnetic poly(GMA-MMA) was 23.4 mg g(-1). The activity yield of the lipase immobilized on the spacer-arm attached magnetic beads was up to 81%. Kinetic analysis shows that the dependence of lipolytic activity of both free and immobilized lipase on trybutyrin substrate concentration can be described by Michaelis-Menten model with good agreement. The estimated Michaelis constants (Km) for the free and immobilized lipase are 2.6 and 12.3 mM, respectively. The V-max values of free and immobilized enzymes were calculated as 984 and 773 U/mg enzymes, respectively. Employment of immobilization seemed to result in an increase in K-m and a decrease in V-max. Optimal operational temperature was 5 degrees C higher for immobilized enzyme than that of the free counterpart. Thermal and storage stabilities were found to he increase with immobilization. (c) 2008 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
lipase, immobilized enzymes, enzyme stability, enzyme kinetic, magnetic beads
Kaynak
Journal Of Molecular Catalysis B-Enzymatic
WoS Q Değeri
Q2
Scopus Q Değeri
N/A
Cilt
55
Sayı
1-2
Künye
closedAccess
