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URN etd-0210111-125244 Statistics This thesis had been viewed 2068 times. Download 1507 times. Author Chou-Chiang Kuo Author's Email Address No Public. Department Bioengineering Year 2010 Semester 1 Degree Ph.D. Type of Document Doctoral Dissertation Language zh-TW.Big5 Chinese Page Count 121 Title Produce of nattokinase and cyclodextrin glucanotransferase by Bacillus sp. Keyword Bacillus sp. cyclodextrin glucanotransferase nattokinase nattokinase cyclodextrin glucanotransferase Bacillus sp. Abstract A strain was isolated from a traditional natto in Japan, and identified the bacteria as Bacillus subtilis by using API CHB50 kits. It was employed for production of nattokinase by shaking culture at 180 rpm and 37 牵C. The optimum medium composition was : 30 g/L soybean flour, 30 g/L glucose, 5 g/L CaCO3 , 5 g/L KH2PO4 and 1 g/L MgSO4．7H2O, with which the nattokinase activity of 23.9 unit/mL was obtained after 48 h.
The batch fermentation using the same medium as in the shaking culture at 300 rpm, 1 vvm of aeration, and 37 牵C, 58.2 unit/mL of nattokinase was achieved after 30 h cultivation.A fed-batch fermentation was performed to control the glucose concentration in the range of 10~20 g/L, in which the nattokinase activity of 107.0 unit/mL was achieved after 29 h.
The nattokinase mocular weight is 27,470 by gel filtration. It was stable at pH 5~8. Addition of and Ca2+ and Mg2+ could enhance the enzyme activity, but 23.3% and 3.4% activity at 24 h retained when adding 50 mM Cu2+ or Hg2+ in the medium.
The other study of this dissertation was focused on the production of cyclodextrin glucanotransferase (CGTase) by Bacillus circulans No. 38-2 (BCRC 10094) in alkaline medium under various conditions. The batch fermentation was performed to achieve CGTase activity of 15.48 unit/mL at 33 牵C using the following medium, 20 g/L soluble starch, 20 g/L yeast extract, 10 g/L Na2CO3, 1 g/L KH2PO4, 1 g/L K2HPO4, 0.2 g/L CaCl2, 0.2 g/L MgSO4．7H2O and 0.2 g/L Mn(NO3)2.
In a continuous fermentation, 1.2~1.5 unit/mL,2.0~2.2 unit/mL and 9.8~10.0 unit/mL were achieved at respective diluting rate of 0.15 h-1 , 0.11 h-1 and 0.075 h-1. The results indicated that the volumetric activity (0.74 ~ 0.75 unit/mL-h) was achieved for the continuous fermentation at a dilution rate of 0.075 h-1, (0.18 ~ 0.23 unit/mL-h) at 0.15 h-1, and (0.22 ~ 0.24 unit/mL-h) at 0.11 h-1, in comparison whit the volumetric activity of 1.11 unit/mL-h respectively for a batch fermentation.
Advisor Committee Kow-Jen Duan - advisor
Files Date of Defense 2011-01-25 Date of Submission 2011-02-11