Lipid Class Composition of the Microalga Pavlova lutheri: Eicosapentaenoic and Docosahexaenoic Acids

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Abstract
The lipid classes of Pavlova lutheri, cultivated in semicontinuous mode, were studied by thin-layer chromatography and gas chromatography in attempts to describe the distribution of fatty acid residues within its lipid pool, with special emphasis on eicosapentaenoic (C20:5n−3, EPA) and docosahexaenoic (C22:6n−3, DHA) acids. Neutral lipids and glycolipids were the major constituents and accounted for ∼57 and 24% of the total fatty acid residues (TFA), respectively. Phospholipids accounted for ∼10% of TFA. Two lipid classes, acylated steryl glycosides (SG) and diphosphatidylglycerols (DPG), were eventually identified in P. lutheri for the first time. The nonpolar fraction was mainly composed of triacylglycerol (TAG), whereas the polar fraction was mainly composed of monogalactosylacylglycerols (MGDG). The distribution of total EPA and DHA within the lipid pool was calculated in attempts to ascertain the quality of said microalgae as a feed source, as well as the possibility of enhancement of individual fatty acid production and extraction thereafter. EPA was especially concentrated in MGDG (∼45%) and TAG (∼33%); conversely, DHA was dispersed through various classes, especially within TAG (∼27%), DPG (∼22%), and betaine lipids (21%). Keywords: DHA; EPA; lipid classes; thin-layer chromatography; aquaculture