博士 / 國立成功大學 / 化學工程學系碩博士班 / 97 / The bio-fuel production from photosynthetic microorganisms is considered as a process to produce renewable energy for global warming mitigation. For mass production of bio-fuel, the economic feasibility of microalgal culture greatly depends on the productivity of biomass and lipids. In this study, an open tank photobioreactor containing transparent rectangular chambers (TRCs) was developed to improve the photosynthetic efficiency of microalgal cultivation. The average irradiance, Iav, was calculated by Lambert-Beer’s law, and was used to determine the light conditions in the cultivation system. The photobioreactor provided large areas of illumination that improved the effective utilization of light energy for microalgae growth and created a good artificial environment for a high rate of cell growth, even at low Iav. The biomass concentration of Chlorella sp. reached 3.745 g L-1 on the 13th day, with biomass productivity of 0.340 g L-1d-1. The total biomass obtained was 56% more than that of similar culture systems without TRCs. Different cultivation modes can affect the growth rate and biochemical composition of microalgae. In fed-batch cultivation, the highest lipid content was obtained by feeding 0.025 g L-1 of urea during the stationary phase. However, a repeated batch culture was carried out by harvesting the culture and renewing urea at 0.025 g L-1 each time when the cultivation achieved the early stationary phase. The maximum lipid productivity of 0.139 g d-1 L-1 in the repeated batch culture was highest in comparison with those in the batch and fed-batch cultivations. For maximizing the biomass and lipid production, the operating conditions of the culture system are determined by using Logistic model and Luedeking-Piret equation - parametric equations describing the growth of microalgae and lipid production, respectively. The objective of the optimal operation for the repeated batch culture is to determine the highest biomass yield. The optimal operating conditions of the preliminary batch culture time, cycle time, and renewal rate are 1.5 days, 0.5 days and 31%, respectively. And the highest biomass productivity of Chlorella sp. was 0.481 g L-1 d-1. The predicted results are in good agreement with the experimental ones in the cultivation as demonstrated having a relative error of 4.0%. The optimal operating conditions of the preliminary batch culture time, cycle time, and renewal rate are 2.0 days, 0.5 days and 27%, respectively. And the highest lipid productivity of Chlorella sp. was 0.144 g L-1 d-1. Consequently, mass production of biomass and lipid from microalgae for bio-fuel production can be successfully accomplished by the photobioreactor design and using an optimal operation of repeated batch culture.
| Identifer | oai:union.ndltd.org:TW/097NCKU5063025 |
| Date | January 2009 |
| Creators | Chih-Hung Hsieh, 謝誌鴻 |
| Contributors | Wen-Teng Wu, 吳文騰 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 158 |
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