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URN etd-0731109-151606 Statistics This thesis had been viewed 4314 times. Download 1431 times. Author Shu-kuan Shih Author's Email Address No Public. Department Bioengineering Year 2008 Semester 2 Degree Master Type of Document Master's Thesis Language zh-TW.Big5 Chinese Page Count 102 Title The heterologous expression of nattokinase using different plasmids and its coexpression with Vitreoscilla hemoglobin in Escherichia coli Keyword hemoglobin Vitreoscilla nattokinase nattokinase Vitreoscilla hemoglobin Abstract In this study, the Vitreoscilla hemoglobin (VHb) gene and the double VHb gene (dVHb) derived from the fusion of two single VHb genes were coexpressed with nattokinase in Escherichia coli. In the presence of VHb or dVHb and using TB containing betaine and sorbitol as culture medium, the maximal intra- and extracellular activities were about 2.5 and 2.6 U/ml, respectively, which were obtained 4 and 20 h, respectively, after induction with IPTG. The nattokinase activity resulted from coexpression with VHb was increased by 27 % in comparison with that expressed alone. The specific activities of pProNAT、pVN and pdVN are 384、402 and 440 U/mg, respectively.The nattokianse gene was also inserted into pET20b, pET23am, pET24a and pDual374 (a Bacillus subtilis plasmid). However, all the expressions from these recombinant plasmids were lower than that from the recombinant pET26b with the corresponding activities of 1.1、0.88、0.7 、0.028 and 0.025 U/ml, respectively. Advisor Committee I-Ching Kuan - advisor
Chi-Yang Yu - co-chair
Ming-Kai Chen - co-chair
Files Date of Defense 2009-07-20 Date of Submission 2009-08-03