Changes in pigments profile in the green alga Haeamtococcus pluvialis exposed to environmental stresses

Haematococcus green culture starved for either nitrogen or phosphate accumulated astaxanthin up to 4% cell dry wt (2.6 g l^-1). While under nitrogen starvation astaxanthin accumulation was faster (maximum achieved after 8 days in comparison to 14 days in the phosphate-starved culture) and accompanied by a drop in the chlorophyll content per cell down to 50% of its original value (30 pg cell^-1); in the phosphate-starved culture this parameter did not change. HPLC profiles of carotenoids monitored along the starvation process revealed that astaxanthin esters accounted for more than 99% of total carotenoids at the end of the exposure period at both starvations.