초록
<P><B>Abstract</B></P> <P> <I>Haematococcus pluvialis</I> is a green microalga of major interest to industry based on its ability to produce large amounts of astaxanthin. Biosynthesis of astaxanthin and its mono- and di-esters was significantly stimulated under 150 μmol m<SUP>−2</SUP> s<SUP>−1</SUP> of white LED (W-150) compared with lower light intensities, but the highest astaxanthin amounts were produced under 70 μmol m<SUP>−2</SUP> s<SUP>−1</SUP> of blue LED (B-70). Transcripts of astaxanthin biosynthesis genes <I>psy</I>, <I>crtO</I>, and <I>bkt2</I> were upregulated under W-150, while <I>psy</I>, <I>lcy</I>, <I>crtO</I>, and <I>crtR-B</I> were upregulated by B-70. Total fatty acid content and biosynthesis genes <I>fata</I> and all <I>dgat</I> genes were induced under W-150, while C18:3n6 biosynthesis and <I>dgat2a</I> expression were specifically stimulated by B-70 which was correlated to astaxanthin ester biosynthesis. Nitrogen starvation, various LEDs and the identified upregulated genes may provide useful tools for future metabolic engineering to significantly increase free astaxanthin, its esters and fatty acid precursors in <I>H. pluvialis</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> LEDs provide useful tools to stimulate <I>Haematococcus</I> astaxanthin biosynthesis. </LI> <LI> High intensity white and blue LED significantly increased astaxanthin content. </LI> <LI> Total fatty acid content was induced by high intensity white LED. </LI> <LI> Astaxanthin and fatty acid biosynthesis genes are regulated by different LEDs. </LI> <LI> Five <I>H. pluvialis dgat</I> genes were identified and <I>dgat2a</I> was induced by blue LED. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>