Аннотация:We report on a novel arctic strain BM1 of a carotenogenic
chlorophyte from a coastal habitat with harsh environmental conditions
(wide variations in solar irradiance, temperature, salinity and nutrient
availability) identified as Haematococcus pluvialis Flotow. Increased (25‰)
salinity exerted no adverse effect on the growth of the green BM1 cells.
Under stressful conditions (high light, nitrogen and phosphorus
deprivation), green vegetative cells of H. pluvialis BM1 grown in BG11
medium formed non-motile palmelloid cells and, eventually,
hematocysts capable of a massive accumulation of the keto-carotenoid
astaxanthin with a high nutraceutical and therapeutic potential.
Routinely, astaxanthin was accumulated at the level of 4% of the cell dry
weight (DW), reaching, under prolonged stress, 5.5% DW. Astaxanthin
was predominantly accumulated in the form of mono- and diesters of
fatty acids from C16 and C18 families. The palmelloids and hematocysts
were characterized by the formation of red-colored cytoplasmic lipid
droplets, increasingly large in size and number. The lipid droplets tended
to merge and occupied almost the entire volume of the cell at the
advanced stages of stress-induced carotenogenesis. The potential
application of the new strain for the production of astaxanthin is
discussed in comparison with the H. pluvialis strains currently employed in microalgal biotechnology.