| Project/Area Number |
14550742
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
化学工学一般
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| Research Institution | Keio University |
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Principal Investigator |
TERASAKA Koichi Keio University, Faculty of Science and Technology, Department of Applied Chemistry, Associate Professor, 理工学部, 助教授 (00245606)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUDA Hisashi National Research Institute of Brewing, Enzyme Engineering Division, Senior Researcher, 酵素工学研究室, 主任研究員
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Xanthan / Thickening Agent / Viscous Liquid / Non-Newtonian Liquid / Oxygen Transfer / Bubble Column / Gas Holdup / Chemical Reactor Engineering / 非ニュートン液体 / バイオリアクター / 降伏応力 |
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| Research Abstract |
Xanthan which is a natural product by Xanthomonas campestris is very useful thickener and additive for food. The production process for xanthan is usually utilized stirred tank bioreactors due to well fermentation in industry. However, the yield stress of culture medium increases rapidly with fermentation so that gas-liquid mixing in stirred tank becomes sometimes poor. Even if a power input for impeller increases to keep mixing well, the liquid far from the impeller becomes stagnant as well as the fungi may be damaged by large shear stress dose to the impeller. When the fungi die due to shortage of oxygen in medium, the xanthan fermentation finishes. For dilute concentration of xanthan gum produced in the solution, large evaporation or separation processes must be required in separation and purification process. In those downstream process, a large amount of waste solutions generates.
On the other hand, bubble columns are well known as good aerobic reactors whose mixture is done by bub
… More
ble convection. Moreover, bubble columns can be easily sterilized and scaling-up.
In this study, the purpose is to develop a bubble column bioreactor for the higher concentrated xanthan production up to protect water environment. This study was proceeded as following steps :
(1)Fermentation on agar
(2)Fermentation in flask and small bubble column
(3)Xanthan production in a stirred tank bioreactor.
(4)Xanthan production in a standard bubble column
(5)Development of novel bubble column bioreactor having high oxygen transfer
Oxygen concentration decreased with fermentation in both stirred tank and standard bubble column. For the xanthan fermentation, the oxygen transfer into culture medium limited the xanthan production due to the liquid became very viscous. Of all bioreactors used in this study, the partitioned bubble column has the higher oxygen transfer coefficient even in the most viscous xanthan solution. Therefore, the proposed bubble column bioreactor is suitable more efficiently to produce xanthan than the other processes. Less
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