초록
<P><B>Abstract</B></P> <P>The influence of 20 standard amino acids was investigated on growth, lipid accumulation, docosahexaenoic acid (DHA) production and cell biochemical composition of <I>Crypthecodinium cohnii</I>. <I>C. cohnii</I> efficiently utilize organic nitrogen (predominantly threonine and to a lesser extent tyrosine and serine) as compared to inorganic nitrogen (NH<SUB>4</SUB>)<SUB>2</SUB>SO<SUB>4</SUB>. However, No significant effect was observed on major biochemical composition of <I>C. cohnii</I> (lipids, carbohydrates and proteins) under N limitation or supplementation with different N-sources. Key lipogenic enzymes glucose-6-phosphate dehydrogenase, ATP-citrate lyase, fatty acid synthase, malic enzyme, citrate synthase (CS), NAD<SUP>+</SUP> and NADP<SUP>+</SUP> dependent isocitrate dehydrogenase were shown to be vital in lipogenesis of <I>C. cohnii</I>. Our results indicated that the process of lipid accumulation in <I>C. cohnii</I> is growth-associated and does not depend upon the trigger of nitrogen depletion. This unusual behavior would suggest that the metabolism of the cells may not be entirely the same as in other lipid-accumulating microorganisms.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Individual affects of 20 standard amino acids was investigated on <I>C. cohnii</I>. </LI> <LI> <I>C. cohnii</I> grow better on threonine, serine and tyrosine as nitrogen (N) source. </LI> <LI> Lipid accumulation in <I>C. cohnii</I> does not depend upon the trigger of nitrogen depletion. </LI> <LI> N-limitation has negative effect on overall lipid and DHA productivity of <I>C. cohnii.</I> </LI> <LI> Metabolic activities changes were complimented with growth and lipid accumulation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>