Enantioselective hydrolysis of (R/S)-Naproxen methyl ester with sol–gel encapculated lipase in presence of calix[n]arene derivatives

Selcuk University, Department of Chemistry, 42031 Konya, Turkey
Applied Catalysis A General (Impact Factor: 3.94). 11/2009; 369(1-2):36-41. DOI: 10.1016/j.apcata.2009.08.030


Lipases are enzymes that catalyses a variety of reactions, such esterifications, interesterification and hydrolysis. Several methods have been reported for the immobilization of lipases, such as deposition onto solid supports, covalent binding and encapsulation within a polymer matrix or silica glasses obtained by sol–gel techniques. In this study, the Candida rugosa lipase was encapsulated within a chemically inert sol–gel support prepared by polycondensation by tetraetoxysilane (TEOS) and octyltrietoxysilane (OTES) in the presence and absence of calix[n]arene, calix[n]-NH2 and calix[n]-COOH (n=4, 6, 8) compounds as additives. The catalytic activity of the encapsulated lipases was evaluated into model reactions, i.e. the hydrolysis of p-nitrophenylpalmitate (p-NPP), and the enantioselective hydrolysis of rasemic Naproxen methyl ester that was studied in aqueous buffer solution/isooctane reaction system.The results indicated that the particularly calix[4,6]-NH2 and calix[6]-COOH based encapsulated lipases had higher conversion and enantioselectivity compared to the sol–gel free lipase.

42 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: No-load and short-circuit conditions are analyzed for the soft-switched phase-shifted full-bridge DC-DC power convertor topology. Some potential problems are identified and possible solutions are discussed
    Telecommunications Energy Conference, 1994. INTELEC '94., 16th International; 01/1994
  • [Show abstract] [Hide abstract]
    ABSTRACT: Candida rugosa lipase (CRL) was immobilized on glutaraldehyde-activated aminopropyl glass beads by using covalent binding method or sol-gel encapsulation procedure and improved considerably by fluoride-catalyzed hydrolysis of mixtures of RSi(OCH3)3 and Si(OCH3)4. The catalytic properties of the immobilized lipases were evaluated into model reactions, i.e. the hydrolysis of p-nitrophenylpalmitate (p-NPP). It has been observed that the percent activity yield of the encapsulated lipase was 166.9, which is 5.5 times higher than that of the covalently immobilized lipase. The enantioselective hydrolysis of racemic Naproxen methyl ester by immobilized lipase was studied in aqueous buffer solution/isooctane reaction system and it was noticed that particularly, the glass beads based encapsulated lipases had higher conversion and enantioselectivity compared to covalently immobilized lipase. In short, the study confirms an excellent enantioselectivity (E>400) for the encapsulated lipase with an ee value of 98% for S-Naproxen.
    Bioresource Technology 01/2011; 102(2):499-506. DOI:10.1016/j.biortech.2010.08.083 · 4.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Enzymatic catalysis has been pursued extensively in a wide range of important chemical processes for their unparalleled selectivity and mild reaction conditions. However, enzymes are usually costly and easy to inactivate in their free forms. Immobilization is the key to optimizing the in-service performance of an enzyme in industrial processes, particularly in the field of non-aqueous phase catalysis. Since the immobilization process for enzymes will inevitably result in some loss of activity, improving the activity retention of the immobilized enzyme is critical. To some extent, the performance of an immobilized enzyme is mainly governed by the supports used for immobilization, thus it is important to fully understand the properties of supporting materials and immobilization processes. In recent years, there has been growing concern in using polymeric materials as supports for their good mechanical and easily adjustable properties. Furthermore, a great many work has been done in order to improve the activity retention and stabilities of immobilized enzymes. Some introduce a spacer arm onto the support surface to improve the enzyme mobility. The support surface is also modified towards biocompatibility to reduce non-biospecific interactions between the enzyme and support. Besides, natural materials can be used directly as supporting materials owning to their inert and biocompatible properties. This review is focused on recent advances in using polymeric materials as hosts for lipase immobilization by two different methods, surface attachment and encapsulation. Polymeric materials of different forms, such as particles, membranes and nanofibers, are discussed in detail. The prospective applications of immobilized enzymes, especially the enzyme-immobilized membrane bioreactors (EMBR) are also discussed.
    BMB reports 02/2011; 44(2):87-95. DOI:10.5483/BMBRep.2011.44.2.87 · 2.60 Impact Factor
Show more