Long-chain alkenones and related compounds in the benthic haptophyte Chrysotila lamellosa Anand HAP 17

The neutral lipid compositions of the coastal haptophyte Chrysotila lamellosa HAP 17 grown in batch culture at 10 and 20 degrees C have been determined. A comparison was also made between the lipid compositions of cells harvested in early and late stationary phase. This species contains a suite of very long-chain C37-C40 alkenones and alkenoates as found in a few microalgae from the Haptophyta. The distributions of these compounds show some differences to earlier reports of different strains of this alga, which are only in part attributable to culture conditions. A suite of long-chain alkenols, the reduced form of the alkenones, was characterized for the first time. The abundance of these compounds was only 1.5% of that of the corresponding alkenones, and the relative proportion of C37-C38 constituents depended on growth temperature. These data show that haptophyte algae are a possible source of the alkenols found in some marine sediments, but the small amounts found suggest that other sources such as bacterial reduction of alkenones are more likely in highly reducing sediments. A mixture of C29-C33 n-alkenes, dominated by the C(31:1) monoene, was found in marked contrast to previous analyses of other strains which reported only the presence of a C(31:2) diene. The sterol distribution included the common haptophyte sterol 24alpha-methylcholesta-5,22E-dien-3beta-ol (epi-brassicasterol) as well as significant amounts of delta5- and delta(5.22)-C29 sterols.