Enhancing EPA Content in an Arctic Diatom: A Factorial Design Study to Evaluate Interactive Effects of Growth Factors

• Published in: Frontiers in Plant Science
• Main Authors: Pia Steinrücken, Svein A. Mjøs, Siv K. Prestegard, Svein R. Erga
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2018
• Subjects: eicosapentaenoic acid (EPA); arctic diatom; factorial design; salinity; growth phase; interactive effects; Plant culture; SB1-1110; Arctic
• Online Access: https://doi.org/10.3389/fpls.2018.00491; https://doaj.org/article/09e6114ce2364bd399a978f50aa51e47

Microalgae with a high content of the omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are of great demand for microalgae-based technologies. An Arctic strain of the diatom Attheya septentrionalis was shown in previous experiments to increase its EPA content from 3.0 to 4.6% of dry weight (DW) in the nutrient-replete exponential phase and nutrient-depleted stationary phase, respectively. In the present study, a factorial-design experiment was used, to investigate this effect in more detail and in combination with varying salinities and irradiances. A mathematical model revealed that both growth phase and salinity, alone and in combination, influenced the EPA content significantly. Maximum EPA values of 7.1% DW were obtained at a salinity of 22 and after 5 days in stationary phase, and might be related to a decreased silica content, an accumulation of storage lipids containing EPA, or both. However, growth rates were lower for low salinity (0.54 and 0.57 d−1) than high salinity (0.77 and 0.98 d−1) cultures.