Correlation Between Lipid And Carotenoid Synthesis And Photosynthetic Capacity Under Different Stress Conditions In Haematococcns Pluvialis

Haematococcus pluvialis is a unicellular green alga fresh water bodies. When greencells encounter stress conditions such as nitrogen deficiency, high light intensity, the algarapidly differentiates from a vegetative stage into a resting stage, formingaplanospores.Within a fewdays, cells increase in volume, produce a very tough cell wall,and accumulate large amounts of a red astaxanthin, which is deposited in extraplastidialoil bodies. Recently, H. pluvialis has been demonstrated to have significant potential forbiofuel production. To explore the correlation between total lipid content and otherphysiological parameters under stress conditions, responses of H. pluvialis to high lightintensity (HL), nitrogen deprivation (-N), and high light intensity with nitrogendeprivation (HL-N) were investigated. The total lipid content of control cells was12.01%dw, whereas that of cells exposed to HL,-N, and HL-N conditions was56.92,46.71, and46.87%dw, respectively. Fatty acid profile was similar under all conditions, with maincomponents including palmitic acid, linoleic acid, and linolenic acid. In the stressconditions, the total carotenoids and astaxanthin content increased and the chlorophylldecreased. The studies have indicated that Fv/Fmand YII would be decreased and NPQincreased. A good correlation was found between individual carotenoid and total lipids,regardless of culture conditions. Photosynthetic parameters and lipid content werewell-correlated, suggesting that PAM fluorometry could be a convenient tool to monitorcellular total lipids.