| Summary: | 碩士 === 元智大學 === 生物科技與工程研究所 === 106 === Ectoine and Hydroxyectoine are compatible solutes produced by halophilic or halotolerant microorganisms in extremely saline environments to protect cellular activity. Ectoine and Hydroxyectoine have the functions of regulating osmotic pressure balance, protecting cell structure and maintaining enzyme activity. Between them, Hydroxyectoine has an extra -OH group in structure than Ectoine, which can replace water and partial water molecule loss in reaction. This stabilizes the natural structure of biopolymers, thereby enhancing the commercial value of Hydroxyectoine. Therefore, the main purpose of this study was to find a strain with superior performance in Hydroxyectoine production, and to achieve higher Hydroxyectoine production through regulation of culture conditions. Among the many strains that produce Ectoine and Hydroxyectoine, Corynebacterium glutamicum, which prefers to produce Hydroxyectoine, was used as a research object. In this study, we investigate the effect of Ectoine and Hydroxyectoine production by different environmental factors (i.e. rotation speed, temperature, pH and salt concentration) and medium compositions (i.e. carbon source, nitrogen source, iron ion and ketoglutaric acid). The results show that the best Ectoine and Hydroxyectoine production is 0.096 g/L and 2.579 g/L when C. glutamicum were incubated at 200 rpm, 30 °C, pH 9 and 0.5 M salt concentrations. In the screening results of the medium composition, it was found that when the carbon source was selected from yeast extract, the nitrogen source was Ammonium sulfate, and 0.5 mM iron ion and 75 mM ketoglutaric acid were added, the Ectoine yield was increased from 0.096 g/L to 0.1 g/L. Hydroxyectoine production increased from 2.579 g/L to 3.15 g/L. Taking into account the fact that the changes in culture conditions have no significant difference in the production of Hydroxyectoine by C. glutamicum, this study will follow up on different fermentation strategies and expect to significantly increase the production of Hydroxyectoine by C. glutamicum.
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