Feasibility study on Applications of Indigenous Functioning microalgae

• Main Authors: Chi-Huan Lee, 李季桓
• Other Authors: Bor-Yann Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/29748564865252001238

碩士 === 國立宜蘭大學 === 化學工程與材料工程學系碩士班 === 103 === To make use of Taiwan’s natural resources for sustainable development, exploration of abundant water resources (e.g., indigenous microalgae) around Taiwan’s water bodies would be of great significance. This study also chose eastern Taiwan’s water bodies to screen high suctioning microalgal species for high-value product generation via electrochemical impedance inspections. Next, GC analyses upon various biomass could be applied to determine whether the capabilities to produce DHA (docosahexaenoic acid (22: 6n-3)) were expressed. Using strategies or hostile environmental stress to stimulate production, the associations of microalgal growth and lipid production were inspected at different temperatures (15 ~ 40℃). Among different nitrogen sources for high DHA production, NH4+-N was promising for DHA production (6.54 %), but not for growth (DCW 2.12 g L-1). Thus, organic nitrogen source-yeast extract was used to have favorable cell growth (3.41 g L-1) as well as DHA production (6.58 %). Thus, two-stage fermentation strategy was applied for maximal DHA production and cellular growth. Meanwhile, regarding limiting nutrient resources at C/N ratios = 25~100, optimal DCW (4.31 g L-1) and total lipid content (26.86 %) could be achieved at C/N ratio of 55/1. To consider industrial practicability for operation, DHA productions of two-stage fermentation at C/N ratio of 35, 45, 55 and 65 were 9.67, 8.12, 13.36 and 10.33 %, respectively. In addition, time-series profiles of C16:0 also showed high accumulation (8.67 %) of DHA at C/N ratio 2.5. At C/N ratio of 55, DHA content tended to be saturated likely due to optimal conversion of low carbon number lipids to DHA. Apparently, these indicated that maximal DHA production could be achieved via optimal stimulating supplementations or limiting nutrients.