Citation
Basri, Mahiran
(1993)
Chemical Modification of Lipase and its Immobilization on
Polymer Beads for Use in Organic Synthesis.
PhD thesis, Universiti Pertanian Malaysia.
Abstract
A simple and effective method to produce a more active,
stable and practical lipase preparation was identified. Soluble
lipase from Candida rugosa was modified with different types
of hydrophobic chemical modifying reagents.
The esterification activities of the modified lipases
were enhanced following their modification. The degree of
activity enhancement depends on the type and molecular weight
of the modifiers used and the degree of modification of the
enzyme.A lower degree of enzyme derivatization was required
for modification with the high molecular weight modifiers to
attain maximal activities. In the case of
monomethoxypolyethyleneglycol (PEG), however, maximal activity
was attained only after exhaustive modification. The opt imum esterificat ion temperature and preference of
fatty acids as acyldonors of the modified lipases were very
similar to those of the native enzyme. Both were more active
in non-polarsolvents than in polarsolvents. The modified
lipases showed higher thermostability, solvent stability and
storage stability compared to the native lipase. The lipase
modified with PEG 1900 was the most thermostable, and that
modified with methyl 4-phenylbutyrimidate (imidoester VI) was
the most stable when incubated in benzene for ten days. The
bests to rage condition was at low temperature and in the
lyophilized form.
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