The effect of spacer arm on hydrolytic and synthetic activity of Candida rugosa lipase immobilized on silica gel
Yükleniyor...
Tarih
2009
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Bv
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Candida rugosa lipase was covalently immobilized onto silica gel in two different ways: via glutaraldehyde (L-GAL) and via hydrophobic spacer arm (1,6 diamino hexane) (L-SA). Free lipase, L-GAL and L-SA were used to investigate the hydrolysis of two different substrates, namely p-nitrophenyl palmytate (pNPP) and p-nitrophenyl acetate (pNPA), both in aqueous medium. In addition, these lipase samples were used to synthesize the pNPP from p-nitrophenol (pNP) and palmytic acid (PA) and pNPA from pNP and acetic acid (AA), both in hexane medium. Hydrolytic and synthetic activities of L-SA were higher than those of free lipase and LGAL, Synthetic activities of free lipase, LGAL and LSA for pNPA in the presence of pNP and AA within hexane medium were higher than those of hydrolytic activities for pNPA in aqueous medium. The same tendency was also observed with pNPP. The effects of pH and temperature on hydrolytic and synthetic activities were investigated for all lipase preparations. Operational stability was the highest for L-GAL, and L-SA when these enzymes were used for pNPP synthesis and in hexane medium, after 100 repeated uses, 68% and 51% of initial activities remained, respectively, at the end of 100 repeated cycles. Free lipase lost all of its activity within 15 and 20 days when stored at 25 degrees C and 5 degrees C, respectively. However. L-GAL showed 54% and 70% of initial activity at the end of 60 storage days at 25 degrees C and 5 degrees C, respectively. while these values were observed as 36% and 60% for L-SA. (C) 2008 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
Lipase, Immobilization, Spacer arm, Synthetic activity, Hydrolytic activity
Kaynak
Journal of Molecular Catalysis B-Enzymatic
WoS Q Değeri
Q2
Scopus Q Değeri
N/A
Cilt
56
Sayı
4
