碩士 / 大葉大學 / 環境工程學系碩士班 / 99 / In the search of the optimal condition for Immobilization of Bacillus subtilis natto by RSM, there factors (mixing time, PVA, concentration and alginate concentration) were investigated. The results showed that the optimal concentration for immobilization was mixing time 2.45 hr, PVA concentration 9.05 g/100 ml and alginate concentration 0.91 g/100 ml. The immobilization cells thus obtained produced 79.14 g/L of Levan when they were cultivated in SM medium for 30hr, in addition, the immobilized beads were kept intact without any damage.
In all nitrogen sources (urea, peptone, yeast extract and ammonium sulfate) tested, only the peak of ammonium sulfate was not overlapped with that of Levan in the analysis using gel permeation chromatogramphy. Therefore, are ammonium sulfate was chosen as the only nitrogen source for later investigation.
In the production of Levan by batch fermentation, one-factor-at-the-time was used to investigate the optimal condition for Levan production, the result showed that the highest Levan production was 80.63 g/L when ammonium sulfate, sucrose concentration, temperature and pH was 2%, 250 g/L, 37℃ and 6.5, respectively. Although the immobilized beads Stayed intact without any damage after 5 repeat batch fermentation, however, the Levan production was significantly decreased to 5.49 g/L.
In the production of Levan by immobilized cells in continuous fermentation, the highest Levan production (63.81 g/L) was obtained at 30 hr of fermentation, in addition, high Levan production was maintained during 30~76 hr period. The immobilized beads stayed intact without any damage even after 208 hr fermentation continuously.
Although the productivity of Levan in continuous fermentation is not as good as it was in batch mode, the advantage in the energy saving , reduction of labor cost and easy automation control has led continuous fermentation to be a better choice for Levan production. This study has provided valuable information for the mass production of Levan in industrial scale.
| Identifer | oai:union.ndltd.org:TW/099DYU00515013 |
| Date | January 2011 |
| Creators | Lee Jun Wei, 李俊緯 |
| Contributors | Shi Ying Lung, 施英隆 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 114 |
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