碩士 / 國立中興大學 / 環境工程學系所 / 96 / Biodiesel, an alternative diesel fuel, is made from renewable biological source such as vegetable oils and animal fats. It is biodegradable and nontoxic and has low emission profiles. Thus, biodiesel is environmentally beneficial. Using vegetable oils as a source of biodiesel may produce carbon dioxide, but plants can turn the carbon dioxide into oxygen and biomass through photosynthesis. There is no net increase of carbon dioxide, so it becomes an integrated ecosystem. These advantages can solve the problems of energy crisis and carbon dioxide emission.
In the numerous methods of producing biodiesel, using microalgae to accumulate lipids as the material has many advantages, The advantages of applying microalgae include: (1) it utilizes carbon dioxide which is a greenhouse gas as its carbon source; (2) it grows photoautotrophically and has high photosynthetic rate per unit biomass; (3) it has higher oil yield than other higher plant per area surface. However, according to previous studies, its low growth rate limited its application.
In this research, the most important growth factor of domestic microalgae, carbon dioxide, will be concerned, and the optimal carbon dioxide concentration will be found out to promote its growth rate. After promoting the growth rate of microalgae, lipids accumulation in microalgae will be investigated by controlling the ratios of the nitrogen nutrient. The effect of separating growth phase and lipid accumulation phase will also be investigated. Combining these investigations, we should achieve the goal of the maximum growth rate and lipid accumulation of microalgae.
In this investigation, four high lipid accumulating microalgae CHL-4, CHT-SA1, CHT-SB2 and CHT-SB3 were selected. These strains grow well under the condition of 10% of carbon dioxide while this concentration was unfavorable to lipid accumulation. The highest lipid in this series of study of CHL-4, CHT-SA1, CHT-SB2 and CHT-SB3 achieved to 34.82%, 28.67%, 32.97% and 27.53% of cell dry weight, respectively. The highest lipid content of CHL-4, CHT-SB2 and CHT-SB3 appeared in the growth condition of 3% of carbon dioxide and the highest lipid accumulation of CHT-SA1 occurred when it cultivated with aeration. In the experiment of nitrogen limitation, the results exhibited that lipid accumulation of microalgae could not increase but decreased gradually. The low photosynthetic ability of microalgae might affect lipid accumulation although the limitation of nitrogen. The fatty acid of lipid produced by these four strains were mainly C16:0, C18:1, C18:2 and C18:3. Furthermore, the C18:3 was the major portion of total fatty acid and reached to over 30%. Since the compositions of fatty acid were the same as fossil fuels (C14-C20), these strains were potential to be used as the material of biodiesel.
| Identifer | oai:union.ndltd.org:TW/096NCHU5087029 |
| Date | January 2008 |
| Creators | Peng-Shau Lai, 賴芃劭 |
| Contributors | Chi-Mei Lee, 李季眉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 163 |
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