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URN etd-0825115-163310 Statistics This thesis had been viewed 795 times. Download 0 times. Author Shing-Yu Chen Author's Email Address No Public. Department Bioengineering Year 2014 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 134 Title Immobilization of D-amino acid oxidase via
a biomimetic film and its application for the resolution
Keyword D-amino acid oxidase magnetic nanoparticles polydopamine polydopamine magnetic nanoparticles D-amino acid oxidase Abstract In this study, magnetic nanoparticles (MNP) were modified with
polydopamine to form polydopamine-coated MNP (PD-MNP), and both
supports were used for the immobilization of D-amino acid oxidase from Trigonopsis variabilis (TvDAO). The optimal pH for TvDAO was 8.5; both
MNP-TvDAO and PD-MNP-TvDAO had an optimal pH of 8.
PD-MNP-TvDAO had better pH stability than MNP-TvDAO. The optimal temperatures for TvDAO, MNP-TvDAO and PD-MNP-TvDAO were 40, 50 and 55℃, respectively. The activity of MNP-TvDAO decreased to 41% after it was reused four times, while that of PD-MNP-TvDAO retained 45% of initial activity after reused five times. After 10 d of storage at 4℃, the residual activities of TvDAO, MNP-TvDAO and PD-MNP-TvDAO were 33, 80 and 50%, respectively. Immobilized TvDAO was applied to converting D-Met in a mixture D/L-Met to highly valuable 4-methylthio-2-oxobutyric acid (MTOB). Without the addition of catalase, most MTOB produced by
MNP-TvDAO or PD-MNP-TvDAO was spontaneously oxidized to 3-methylthiopropionic acid by H 2 O 2 . With the addition of 1600U of catalase, the conversion of D-Met to MTOB reached 100% after 10 min of reaction, regardless which form of immobilized enzyme was used.
Advisor Committee Chi-Yang Yu - advisor
I-Ching Kuan - co-chair
none - co-chair
Files Date of Defense 2015-07-21 Date of Submission 2015-08-25