Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/23093
Title: Immobilization of enzymes onto nanoporous materials and application as immobilized biocatalyst
Authors: MALIK JAMAL J
Keywords: Mesoporous silicate, SBA-15, Enzyme immobilization, non-aqueous enzymology, thermodynamic water activity, biocatalyst
Issue Date: 4-Apr-2007
Source: MALIK JAMAL J (2007-04-04). Immobilization of enzymes onto nanoporous materials and application as immobilized biocatalyst. ScholarBank@NUS Repository.
Abstract: Mesoporous silicate (purely siliceous SBA-15, thiol functionalized SBA-15 and rod-like SBA-15) have been utilized as hosts for the immobilization of alpha-chymotrypsin and the activities of the immobilized enzymes in aqueous and organic media have been investigated. The activity of alpha-chymotrypsin in aqueous media decreased upon immobilization in pure and thiol functionalized SBA-15 but immobilized alpha-chymotrypsin showed enhanced thermal stability at high temperature (70oC) compared to native alpha-chymotrypsin. Interestingly, alpha-chymotrypsin immobilized in pure and thiol functionalized SBA-15 showed minimal leaching from the support in aqueous buffer due to the strong electrostatic interaction between positively charged enzyme and negatively charged mesoporous silicate. alpha-chymotrypsin immobilized in pure SBA-15 and thiol functionalized SBA-15 showed higher activity in organic media compared to alpha-chymotrypsin immobilized in the commercial silica gel at the thermodynamic wateractivity of 0.22. It is postulated that the higher activity of alpha-chymotrypsin immobilized in mesoporous silicate in organic media as compared with that on commercial silica gel is due to the smaller particle size of mesoporous silicate, which reduces the internal mass transfer limitation and hence increases the activity of the immobilized enzyme. Furthermore, alpha-chymotrypsin loading of 20 wt % in rod-like SBA-15 showed higher catalytic activity compared to other enzyme loading amount as well as alpha-chymotrypsin immobilized onto pure SBA-15 and commercial silica gel at the thermodynamic water activity of 0.22. The optimum thermodynamic water activity of alpha-chymotrypsin immobilized in rod like SBA-15 was found to be 0.55 in either acetonitrile ortetrahydrofuran.
URI: http://scholarbank.nus.edu.sg/handle/10635/23093
Appears in Collections:Master's Theses (Open)

Show full item record
Files in This Item:
File Description SizeFormatAccess SettingsVersion 
thesis.pdf2.73 MBAdobe PDF

OPEN

NoneView/Download

Page view(s)

230
checked on Dec 11, 2017

Download(s)

588
checked on Dec 11, 2017

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.