碩士 / 東海大學 / 化學工程與材料工程學系 / 101 / During cultivation, Rhodotorula glutinis utilized C sorce and released CO2. Moreover, organic acids were synthesized and the pH of culture dropped. As a result, the growth of yeast was inhibited. Scenedesmus obliquus utilized CO2 and released O2 during photosynthesis. The cells growth of R. glutinis and S. obliquus would be raised with light exposed. The metabolites are inhibiative to R. glutinis and S. obliquus in the medium were removed and it was sutable to grow for yeast and algae. The accumulations of biomass and total lipids in the coculture are suitable for biodiesel production.
The biomass concentration of 11.1 ± 0.44 g/L and the total lipids accumulation of 1.777 ± 0.278 g/L were obtained by R. glutinis in the pure culture. The biomass concentration of 2.0 ± 0.06 g/L and the total lipids accumulation of 0.370 ± 0.015 g/L were obtained by S. obliquus in the pure culture. The biomass concentration of 14.05 ± 0.07 g/L and the total lipids accumulation of 3.594 ± 0.251 g/L were obtained in the coculture. It was shown the results of the coculture are better than the pure culture’s. The total percentages of palmitic (C16：0) and oleic acids (C18：1) are raised to 90.99 % of the couclutre from the 84.68 % of R. glutinis and 83.14 % of S. obliquus in the pure culture.
The cells growth and total lipids accumulation are effected by the composition of the medium and the environment. The ratio of inoculation of yeast and algae, the concentration of N source, the concentration of glucose, NaCl, initial pH, the baffle, the temperature and the intensity of light were studied in flaskes. The possipility of scale-up was studied in the 5 L fermentor and 6 L air-lift bioreactor.
The effect of the ratio was unobvious based on the experiment of the ratio of inoculation. Based on N source experiment, the algae prefered inorganic N source (KNO3) and the cells growth were raised with concentration of KNO3 increasing. Ferthermore, the yeast prefered organic N source (Yeast extract, YE). Compared with algae, the cells growth of yeast was progressed better. The higher biomass and total lipids accumulation were obtained from yeast. Under N-limited, the total lipids accumulation is promoted with glucose concentration increased. The biomass of 15.1 ± 1.04 g/L, the total lipids accumulation of 5.952 ± 0.392 g/L and the total lipid content of 39.34 ± 1.05 % are obtained at 50 g/L glucose. The total lipids accumulation and the yield of lutein were advanced with NaCl adding.
The total lipids accumulation was increased 13.4 %. The yield of β-carotene was increased 435 ~ 490 % with the addition of 0.5 g/L NaCl delayed.
The growth of algae was inhibited at high pH based on the pH experiment. The growth of yeast was advanced when the aeration was increased. However, owing to the high concentration of yeast cells the light may have hardly penetrated and its intensity attenuated drastically. As a result, the photosynthesis of algae was inhibited. The temperature 24 ℃ is sutible for the coculture of yeast and algae. The cells growth was stressed under an unsuitable cultivation. The biomass was decreased and the total lipids accumulation was increased about 33~37 %. Based on the light experiment, R. glutinis was promoted when S. obliquus photosynthesized and released O2 with the light. The growth of S. obliquus and R. glutinis were advanced except for the lipids accumulation with the light intensity raised. The higher growth rate of R. glutinis resulted in the shading effect to S. obliquus. Based on 5 L fermentor experiment, the effect of the coculture was advanced with 2 % CO2 added. Based on the 6 L air-lift bioreactor experiment, the biomass of 7.1 g/L was obtained at a coculture with 1.25 g/L KNO3 and 2 g/L YE added. However, the biomass of 6.1 g/L was obtained at a coculture with 0.5 g/L KNO3 added and without YE. It was shown that the shading effect is earthshaking compared to the nutrient in the medium.
| Identifer | oai:union.ndltd.org:TW/101THU00063007 |
| Date | January 2013 |
| Creators | Chen, Lijuan, 陳儷娟 |
| Contributors | Yen, Hongwei, 顏宏偉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 126 |
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