Changes in the fatty acid composition of Phaeodactylum tricornutum and Dunaliella tertiolecta during growth and under phosphorus deficiency

Abstract

Total fatty acid content increased with age in batch cultures of Phaeodactylum tr'cornutum. Chromatographic analysis revealed changes in the fatty acid composition of the diatom grown in natural enriched medium. Particularly noticeable was the storage of palmitic and palmitoleic acids by the end of the growth period, to the detriment of eicosapentaenoic acid. This study also gives evidence of the importance of oleic acid as a precursor in the biosynthesis of long-chain polyunsaturated fatty acids in thls diatom. Phosphorus limitation also led to a significant increase in the total fatty acid cell content of P. tricornutum and Dunaliella tertiolecta. When P. tricornutum was cultured in phosphorusdeficient medium, the fatty acid composition was similar to that of a senescent batch culture. When division rate was reduced, oleic acid content of D. tertiolecta increased, confirming this fatty acid as an intermediate component in the lipid metabolism of this chlorophyte during the division processes.