Fatty acid content in wild type and WZSL mutant of Euglena gracilis - Effects of carbon source and growth conditions

The effects of growth conditions on fatty acid profile were examined in the photosynthetic wild type and in the spontaneous non-photosynthetic WZSL mutant of the unicellular flagellate Euglena gracilis. In the light, the amount of polyunsaturated fatty acids (PUFAs) is higher in the wild type than in the mutant, independent of the carbon source. Among important PUFAs, linolenic acid (18:3 omega3) is present in high amount only in wild type cells grown in the light with any of the tested carbon sources. The content of other PUFAs, such as arachidonic acid (20:4 omega6), EPA (20:5 omega3) and DHA (22:6 omega3), is not correlated with the presence of light or chloroplasts. The main effect of the dark in both strains is to lower the content of PUFAs and mono-unsaturated fatty acids and to increase the content of saturated fatty acids with all the carbon sources.