Fatty acid profiles and their distribution patterns in microalgae: a comprehensive analysis of more than 2000 strains from the SAG culture collection

The fatty acid profiles of 2076 microalgal strains from the culture collection of algae of G？ttingen University (SAG) were determined in the stationary phase. Overall 76 different fatty acids and 10 other lipophilic substances were identified and quantified. The obtained FA profiles were added into a database providing information about fatty acid composition. Using this database we tested whether FA profiles are suitable as chemotaxonomic markers. FA distribution patterns were found to reflect phylogenetic relationships at the level of phyla and classes. In contrast, at lower taxonomic levels, e.g. between closely related species and even among multiple isolates of the same species, FA contents may be rather variable.FA distribution patterns are suitable chemotaxonomic markers to define taxa of higher rank in algae. However, due to their extensive variation at the species level it is difficult to make predictions about the FA profile in a novel isolate.The analysis of the overall fatty acid profiles as well as the occurrence of fatty acids (FAs) in different lipid classes in microalgae is an emerging field which is expected to reveal the identification of novel FAs with a variety of new functional groups [1]. Despite a number of reports has been carried out and published, describing the contents as well as the composition of polyunsaturated fatty acids (PUFAs) in mostly marine microalgae [2-4], systematic approaches that include different or even many genera of microalgae and particularly those from freshwaters or terrestrial habitats are still missing [5].Based on current knowledge, FA composition divides microalgae roughly into two groups, i.e. on one hand the cyanobacteria and green algae (Chlorophyta and Streptophyta) which contain low amounts of FAs, predominantly saturated and mono unsaturated FAs as well as trace amounts of PUFAs, mostly linoleic acid (LA, 18:2(9Z, 12Z): where x:y(z) is a fatty acid containing X carbons and y double bonds in position z count