none

• Main Authors: Yu-Ling Yeh, 葉昱伶
• Other Authors: Yu-Hsiang Lee
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/77424614275931927311

碩士 === 國立中央大學 === 生物醫學工程研究所 === 101 === The value of marine microalgae has long been identified due to their useful products such as polyunsaturated fatty acids, proteins, carotenoids, and polysaccharides. Among various microalgae, Nannochloropsis oculata is a lipid-rich species which can yield up to 68% (w/w) total lipid under appropriate cultivation and thus exhibit high potential for practical applications. To enhance the commercial availability of Nannochloropsis oculata, effectiveness of using polyethylene glycol (PEG) to increase microalgal biomass and lipid production was investigated. We first examined the effects of PEG concentrations on microalgal growth using 0 - 5% (w/v) PEG-6000, and followed by exploring the effects of PEG molecule weights range from 400 to 20000 on microalgal growth, size, as well as on yields of biomass, lipids, and eicosapentaenoic acid. Furthermore, the capacity of PEG to reduce the effect of oxygen inhibition on microalgal growth was also studied in order to assess the adaptability of PEG for use in large-scale and closed setting. Our results showed that PEG-induced osmotic stress in the range of 2.465 - 2.472 MPa can increase microalgal growth. The PEG with higher molecular weight exhibited higher biomass but less lipid productivity under equal concentration of 0.5% (w/v). Among different conditions set in this study, 0.5% (w/v) PEG-20000 enabled to yeld > 50% (w/w) increases in biomass, total lipid and eicosapentaenoic acid amounts after seven days without interference of cellular size, offering the optimal condition for Nannochloropsis oculata cultivation. With another fact that 0.5% (w/v) PEG-20000 enabled to diminish the effect of oxygen inhibition on microalgal growth, the PEG-20000-mediated microalgal cultivation exhibits a high potential for use in industry.