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

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