## 3 Results and Discussion
### Fatty Acids Profile of C. reinhardtii
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{1}{c}{**Fatty Acid**} & \multicolumn{3}{c}{_C. reinhardtii_} & \multicolumn{2}{c}{_Chlorella_} & \multicolumn{2}{c}{_Spirulina_} \\ \hline  & **(mg/g\({}^{-}\))** & **(\%)** & **(mg/g)** & **(\%)** & **(mg/g)** & **(\%)** \\ \hline C16:0 & 16.7 \(\pm\) 0.8 b  & 23.8 \(\pm\) 0.2 & 11.0 \(\pm\) 0.3 b  & 22.2 \(\pm\) 0.1 & 25.9 \(\pm\) 4.6 a  & 57.9 \(\pm\) 0.4 \\ C16:1 _n_-7 & 1.9 \(\pm\) 0.1 b  & 2.7 \(\pm\) 0.1 & 6.5 \(\pm\) 0.1 a  & 13.0 \(\pm\) 0.1 & 0.1 \(\pm\) 0.0 c  & 0.1 \(\pm\) 0.0 \\ C16:4 _n_-3 & 3.9 \(\pm\) 0.1 a  & 5.5 \(\pm\) 0.3 & 0.0 \(\pm\) 0.0 b  & 0.1 \(\pm\) 0.0 & 0.0 \(\pm\) 0.0 b  & 0.1 \(\pm\) 0.0 \\ C18:0 & 1.6 \(\pm\) 0.2 a  & 2.3 \(\pm\) 0.3 & 1.4 \(\pm\) 0.0 a  & 2.8 \(\pm\) 0.1 & 0.7 \(\pm\) 0.0 b  & 1.5 \(\pm\) 0.1 \\ C18:1 _n_-9c & 10.3 \(\pm\) 1.1 c  & 14.7 \(\pm\) 1.6 & 3.5 \(\pm\) 0.1 a  & 7.0 \(\pm\) 0.2 & 0.9 \(\pm\) 0.2 b  & 2.0 \(\pm\) 0.2 \\ C18:2 _n_-6c & 2.7 \(\pm\) 0.2 b  & 3.8 \(\pm\) 0.2 & 15.6 \(\pm\) 0.3 c  & 31.4 \(\pm\) 0.3 & 8.5 \(\pm\) 1.6 a  & 19.0 \(\pm\) 0.2 \\ C18:3 _n_-6 (GLA) & 2.9 \(\pm\) 0.2 a  & 4.1 \(\pm\) 0.3 & 0.0 \(\pm\) 0.0 b  & 0.1 \(\pm\) 0.0 & 8.7 \(\pm\) 1.6 c  & 19.5 \(\pm\) 0.2 \\ C18:3 _n_-3 & 29.8 \(\pm\) 1.9 a  & 42.4 \(\pm\) 1.2 & 11.6 \(\pm\) 0.2 c  & 23.4 \(\pm\) 0.1 & 0.1 \(\pm\) 0.0 a  & 0.1 \(\pm\) 0.1 \\ C20:4 _n_-6 & 0.6 \(\pm\) 0.1 a  & 0.9 \(\pm\) 0.0 & 0.0 \(\pm\) 0.0 b  & 0.1 \(\pm\) 0.0 & 0.0 \(\pm\) 0.0 c  & 0.0 \(\pm\) 0.0 \\ \(\sum_{\rm SFA}\) & 18.3 & 26.02 & 12.4 & 25.0 & 26.6 & 59.4 \\ \(\sum_{\rm USFA}\) & 52.1 & 74.0 & 37.3 & 75.0 & 18.5 & 40.6 \\ \(\sum_{\rm n}\)-3 FA & 33.7 & 47.9 & 11.6 & 23.4 & 0.1 & 0.2 \\ \(\sum_{\rm n}\)-6 FA & 6.2 & 8.7 & 15.7 & 31.6 & 17.2 & 38.3 \\ \(n\)-6/_n_-3 & 0.2 & 0.2 & 1.4 & 1.4 & und & und \\ \hline \hline \end{tabular}  
* Means that share lowercase letters within each row are not significantly different at (\(p\geq 0.05\)) for each fatty acid for the three species. *DW: dry weight; und: undefined due to the very low amount. *C16:0: palmitic acid; C16:+\(n\)3: hexadecetraenoic acid; C18:0:earic acid; C18:1_n_-9c: oleic acid; C18:2 _n_-6c: linoleic acid (LA); C18:3 _n_-6: Gamma-linolenic acid (GLA); C18:3 _n_-3: Alpha-linolenic acid (ALA); C20:4 _n_-6: arachidonic acid; SFA: saturated fatty acid; USFA: unsaturated fatty acid.  
\end{table} 
Table 2: Fatty acid profile of _C. reinhardtii_, _Spirulina_ and _Chlorella_. compared to other sources. Gamma-linolenic acid (GLA) is an \(n\)-6 fatty acid and, once consumed by humans, is a precursor for monoenoic prostaglandandins such as PGE1, an important biologically active compound necessary for reducing chronic inflammation and blood pressure [50]. _C. reinhardtii_ grown under favourable conditions is rich in membrane lipids, which are characterised by their high content of PUFAs (60 mol%), of which, 80% are C18:3 (\(n\)-3), C16: 4 (\(9\) -3), C18: 4 (\(n\)-3), and C18:3 (\(n\)-6) [44]. The \(n\)-3 PUFAs also proved to be present in both plastid and extraplasticid membrane lipids such as monogalactosyldiacylglycerol (MGDG) and phosphatidylethanolamine (PtdEnt) [51]. Many studies have confirmed that _C. reinhardtii_ accumulates triacylglycerglycerol (TAG) once grown in a media limited with nitrogen, sulphur and phosphorous. In these cases, TAGs rich in C16:0, C18:1 and C18:2 accumulate in oil bodies in parallel with an almost 80% reduction in the major plastidial membrane lipids and hence a reduction in \(n\)-3 PUFAs [44]. Unlike plants, where there are distinct genes for plastidial and extraplastidial \(n\)-3 fatty acid desaturases, only one putative \(n\)-3 desaturase seems encoded in _C. reinhardtii_ genome. Several explanations have been suggested, first, the existence of a mechanism to export \(n\)-3 acids from their site of biogenesis to other membranes. Second, the presence of a dual localisation of the \(n\)-3 desaturase homolog (plasti and endoplasmic reticulum) [51]. The ratio \(n\)-6:\(n\)-3 in _C.