Production and supercritical fluid extraction of lutein from Scenedesmus obliquus in an autotrophical cultivation

• Main Authors: Sun, Cheng-Hsiung, 孫證雄
• Other Authors: Yen, Hong-Wei
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/41212115888761825766

碩士 === 東海大學 === 化學工程與材料工程學系 === 99 === In recent years, because the algae have a carbon reduction capacity, high lipid content and rich nutrient ingredients, it gradually attracted much attention. In this study, we explore three research directions by the cultivation of microalgae: (1) the effect of Scenedesmus obliquus concentration and lutein content by changing the environment or the medium composition. The results of this study indicate that an increase in CO2 percentage to 2% and light intensity to 1600 μmolm-2s-1 can enhance Scenedesmus obliquus growth to a maximum of 2.45 g/L and 2.46 g/L; salt will result in the phenomenon of cell growth retardation; methylene blue added will not have any impact. As for the effect of lutein content, 2% carbon dioxide and 1600 μmolm-2s-1 light intensity can increase to 0.40% dw and 0.47% dw; salt and methylene blue added will not cause any effect, (2) scale up experiment and explore the impact of cultivating parameters. We get a light intensity model Biomass(g/L)=0.3574*ln(modified light intensity)-4.1846, and the use of 6.0 L photoreactor verify the credibility of this equation, (3) the ability of supercritical fluid extraction whether to replace the traditional organic solvent extraction method of the possibilities. In this study, the supercritical fluid extraction of lutein is divided into four parts: (a) pressure, (b) temperature, (c) co-solvent type, (d) the optimum amount of co-solvent. The results showed that the increase of pressure and temperature in the SFE operation enhances the lutein recovery yield. However, the enhancement resulting from the increase of temperature and pressure is not significant as compared to the yield from the conventional methanol extraction method. In addition, the increase of temperature leads to them increased impurity observed in the HPLC profile. To further enhance the lutein recovery yield, the addition of a co-solvent in SFE is performed. Of the five solvent powders investigated, ethanol is regarded as the optimum co-solvent for use in lutein extraction. The optimum amount of ethanol to be added in the SFE operation is determined. The best lutein recovery yield obtained is 76.2% (as compared to the conventional methanol extraction method) under the conditions of 400 bar, 70℃ and with ethanol as the co-solvent being added at 0.629 ml/min.