초록
<P><B>Abstract</B></P> <P>Microalgae have emerged as promising resources for highly unsaturated fatty acids. In this study, an indigenous microalga identified as <I>Nannochloropsis oceanica</I> CY2 was grown photoautotrophically to produce eicosapentaenoic acid (EPA; 20:5, n-3). Specific engineering strategies were employed to stimulate EPA accumulation in the microalgal cells. The results show that BG-11 was the most effective medium to grow <I>N. oceanica</I> CY2, giving an EPA content and biomass concentration of 2.38% (per dry cell weight) and 1.53g/l. The EPA content nearly doubled when using the optimal nitrogen source (NaNO<SUB>3</SUB>) at a concentration of 1.50g/l. The illumination system also markedly affected the EPA content for the photoautotrophic microalga. When the microalgal culture was illuminated with a red LED, an impressively high EPA content of 5.5% was obtained. Finally, using semi-batch cultures operations with LED-blue illumination, the EPA content of <I>N. oceanica</I> CY2 was stably maintained at 5.0%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An isolated microalga <I>N. oceanica</I> CY2 exhibits high potential of producing EPA. </LI> <LI> Light intensity and nitrogen source concentration were optimized for EPA production. </LI> <LI> EPA production of <I>N. oceanica</I> CY2 was improved when using LED-blue illumination. </LI> <LI> Combining semi-batch operation and LED PBR resulted in excellent EPA production. </LI> </UL> </P>