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URN etd-0202109-115422 Statistics This thesis had been viewed 4099 times. Download 1283 times. Author Hao-Chieh Hsieh Author's Email Address No Public. Department Bioengineering Year 2008 Semester 1 Degree Master Type of Document Master's Thesis Language English Page Count 100 Title Stabilization of D-amino acid oxidase from Rhodosporidium toruloides by immobilization onto magnetic nanoparticles Keyword Rhodosporidium toruloides Magnetic nanoparticle D-Amino acid oxidase Stabilization Immobilization Immobilization Stabilization D-Amino acid oxidase Magnetic nanoparticle Rhodosporidium toruloides Abstract D-Amino acid oxidase from Rhodosporidium toruloides was expressed by E. coli and immobilized onto glutaraldehyde activated magnetic nanoparticles. Approximately four enzyme molecules were attached to one magnetic nanoparticle when the weight ratio of the enzyme to the support was 0.12. After immobilization, the Tm increased from 45oC of the free form to 55oC, indicating the thermal stability was improved. At the presence of 20 mM hydrogen peroxide, the immobilized form retained 93% of its activity after 300 min while the free form was completely inactivated after 210 min, suggesting the oxidative stability against hydrogen peroxide was also improved. Although the stability was enhanced through immobilization, the catalytic efficiency (kcat/KM) was decreased by 3.5 fold. The immobilized enzyme could be recycled, 15% of the initial activity was retained after 10 reaction cycles. Advisor Committee Chi-Yang Yu - advisor
I-Ching Kuan - co-chair
Ming-Kai Chern - co-chair
Files Date of Defense 2009-01-06 Date of Submission 2009-02-05