High production of unexpected carotenoids in Dinophyceae. Astaxanthin esters from the freshwater dinoflagellate Tovellia sanguinea

A wide range of photopigments biosynthesised by a unialgal cell culture of the red dinoflagellate Tovellia sanguinea, the blooms of which were responsible for the summer reddening of the waters of the Lake Tovel until 1964, have been identified through reversed-phase high pressure liquid chromatography (HPLC) coupled to photodiode array detector (PDAD) and to atmospheric pressure ionisation mass spectrometer (API-MS). Myristoyl and palmitoyl astaxanthin esters were the most abundant pigments of T. sanguinea, whereas other carotenoids, considered to be diagnostic markers for dinoflagellates, were present here only in relatively low amounts. This is the first report where astaxanthin esters have been found as the major pigments in the taxon Dinoflagellata and largely over-expressed in comparison to the light-harvesting carotenoid peridinin. A plausible biogenetic route for the ketocarotenogenesis of T. sanguinea pigments is proposed.