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Title page for etd-0825115-163310


URN etd-0825115-163310 Statistics This thesis had been viewed 884 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
of D/L-methionine
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 indicate in-campus access at 1 years and off-campus access at 3 years
    Date of Defense 2015-07-21 Date of Submission 2015-08-25


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