碩士 / 國立成功大學 / 地球科學系碩博士班 / 101 / Global warming and climate change have become worse due to the increased population and the excess utilization of fossil fuels. The development of CO2 sequestration technologies as well as restrain the CO2 emissions are extremely important purposes for sustainable development of human beings.
Because the cyanobacteria has the ability to fix carbon in high efficiency and the high environmental tolerability characteristics, various countries put their efforts on the development of CO2 fixation technologies for cyanobacteria (or microalgae). In addition to optimize the carbon fixation efficiency of cyanobacteria, the flat plate bio-reactor is chosen to raise the biomass productivity in the optimize biomass concentration and light intensity. After the carbon fixation, the biomass can be use as energy production precursor or high value products, such as carotenoids. However, the cost of CO2 fixation by cyanobacteria and energy production are too high. Valuable products, such as carotenoids, have high potential to reduce the cost. Carotenoids have high economic benefit which can be commonly extracted from cyanobacteria. Carotenoids have ability to decelerate aging and prevent from chronic disease for human beings. Human beings can’t produce carotenoids by themselves but only from the diet. Therefore, in order to fit the demands of CO2 fixation, healthy products and sustainable development, cyanobacteria Thermosynechococcus CL-1 (TCL-1) is cultivated in the flat plate photobioreactors to enhance the CO2 fixation rate and the biomass productivity in this study.
Light intensity and salinity are the key factors that influence carotenoids content and the productivity for cyanobacteria. In addition, for the sake of outdoor cultivation in the future, the diurnal cycle (light / dark) affect the production of carotenoids is also needs to research. In this study, thermophilic (40-62 ℃) and basophilic (pH = 9-12) cyanobacteria Thermosynechococcus sp. CL-1 (TCL-1) is chosen as the fixed carbon dioxide photosynthetic bacteria. In batch operation, TCL-1 in LED light intensity (200-1,200 μE/m2/s), salinity (NaCl 0.03 M、0.25 M and 0.5 M), the LED light / dark (12 hours: 12 hours; used to simulate the natural changes in the circadian cycle), the cyanobacteria cell growth, carbon fixation efficiency and carotenoids content, cell productivity and cost analysis are discussed. The results indicate that the TCL-1 has the maximum specific growth rate、productivity、carbon fixation rate and carotenoids productivity (4.12/d、1.51 g/L/d、2.40 g/L/d and 14.1 mg/L/d, respectively) in the case of LED light intensity of 600μE/m2/s. Cells growth inhibition occurs in the condition of 1,200μE/m2/s due to excessive light. Moreover, salt (NaCl) and LED lights / dark (12:12) was further explored by using different light conditions (200, 600 and 1,000μE/m2/s). The results show that the specific growth rate、productivity、rates of carbon fixation and carotenoids could be reduced to 1.43/d、0.11 g/L/d、0.15 g/L/d and 4.2 mg/L/d, respectively.
The knowledge and outcome obtained from this study would be useful for assessing the feasibility of using microalgae system in practical applications for CO2 mitigation and commercial carotenoids productions.
| Identifer | oai:union.ndltd.org:TW/101NCKU5135006 |
| Date | January 2013 |
| Creators | Fan-YuChueh, 闕凡瑜 |
| Contributors | Shang-De Luo, 羅尚德 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 135 |
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