Accumulation of astaxanthin in flagellated cells of Haematococcus pluvialis - cultural and regulatory aspects

摘要

The effect of nutrient stress on astaxanthin formation in flagellated cells of Haematococcus pluvialis was evaluated under autotrophic conditions. High biomass yield of 3.5 g/l was achieved on phosphate free medium and astaxanthin constituted 1.5% (w/w) on dry weight basis, with a production of 55.6 mg/l. A combination of nitrogen and phosphate limitation was effective in enhancement of astaxanthin content to 2.0 +/- 0.2 % (on dry weight basis), resulting in its production of 3538 mg/l. Actinomycin-D inhibited both cell growth as well as carotenogenesis, while chloramphenicol and 3(3,4-dichlorophenyl)-1,1-dimethyl urea inhibited significantly the secondary carotenoid formation in flagellated cells under low light intensity, with no effect under high light intensity. Cycloheximide inhibited carotenogenesis in both flagellated and encysted cells under low as well as high light intensities. The accumulation of astaxanthin in lipid globules of flagellated cells was detected with staining of algal cells. The results indicated that both cytoplasmic and organellar translational inhibitors play a role in the secondary carotenoid formation in flagellated cells, which depend on light to a greater extent than salinity stress.