碩士 / 義守大學 / 生物技術與化學工程研究所碩士班 / 97 / In recent years, polyunsaturated fatty acids (PUFAs) becomes very important due to their recognition as being beneficial for human health. It has been verified that docosahexaenoic acid (DHA) improves neural and retinal development in infants and prevent or treatment of cardiovascular diseases in adult. Therefore, it becomes general tendency to ingest PUFAs from health food. The marine microalgae, which has been recently discovered to have high content of DHA and EPA, has become an alternate source of DHA. It should be worth to employ fermentation technique to obtain a great quantity of DHA.
This study choose a DHA accumulating strain of marine microalgae Crythecodinium cohnii as the experimental strain. Initially, the effects of initial pH, the concentrations of glucose, nitrogen source, K2HPO4, MgSO4 and trace elements on the biomass and DHA yield fermentation were examined. The DHA content of microalgae in the broth was analyzed by gas chromatograph (GC). Then, optimization of medium components was carried out by using response surface methodology (RSM). The optimal medium composition were found to be 60 g/L of glucose, 12.45 g/L of yeast extract, 25 g/L of NaCl, 2.6 g/L of K2HPO4, 3.98 g/L of MgSO4 and 0.01 g/L of FeCl3. From the regression model, the production of DHA was predicted as 677.3 mg/L; while the experimental value was 681.6 ± 1.83 mg/L. It shows that the experimental and predicted values were in good agreement. And the experimental value of optimal medium is 1.47-fold of previous culture medium; while the optimal medium under the 5 L fermentor condition, the DHA yield value is 1.75-fold of previous one.
| Identifer | oai:union.ndltd.org:TW/097ISU05108022 |
| Date | January 2009 |
| Creators | Shih-ho Tsai, 蔡世和 |
| Contributors | Jiumn-Yih Wu, 吳俊毅 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 71 |
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