# Microwave-Assisted Extraction of Fatty Acids from Cultured and Commercial Phytoplankton Species
## 3 Results
### Lipids and Fatty Acids
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & _Arthrospira_ sp. & _Chlorella_ sp. & & _S. torques_ \\ \hline  & **Fatty Acid** & **MAE** & **MAE** & **MAE** & **TE** \\ \hline C10:0 & Capric acid & \(0.11\pm 0.01\)\({}^{\text{a}}\) & 0.20 \(\pm\) 0.01 \({}^{\text{b}}\) & n.a. & n.a. \\ C14:0 & Myristic acid & \(0.93\pm 0.00\)\({}^{\text{a}}\) & 1.46 \(\pm\) 0.18 \({}^{\text{b}}\) & 2.44 \(\pm\) 0.10 \({}^{\text{c}}\) & n.a. \\ C15:0 & Pentadecanoic acid & \(0.44\pm 0.00\)\({}^{\text{a}}\) & 0.88 \(\pm\) 0.06 \({}^{\text{b}}\) & n.a. & n.a. \\ C16:0 & Palmitic acid & 37.41 \(\pm\) 0.29 \({}^{\text{a}}\) & 18.30 \(\pm\) 0.29 \({}^{\text{b}}\) & 34.85 \(\pm\) 0.09 \({}^{\text{c}}\) & 54.36 \(\pm\) 0.10 \\ C16:1 & Palmitoleic acid & 10.77 \(\pm\) 0.24 \({}^{\text{a}}\) & 11.86 \(\pm\) 0.23 \({}^{\text{b}}\) & 8.92 \(\pm\) 0.46 \({}^{\text{c}}\) & 11.17 \(\pm\) 0.11 \\ C17:0 & Heptadecanoic acid & \(0.76\pm 0.02\)\({}^{\text{a}}\) & 0.51 \(\pm\) 0.04 \({}^{\text{b}}\) & n.a. & n.a. \\ C17:1 & Heptadecenoic acid & \(0.78\pm 0.01\)\({}^{\text{a}}\) & 1.86 \(\pm\) 0.13 \({}^{\text{b}}\) & n.a. & n.a. \\ C18:0 & Stearic acid & \(2.13\pm 0.04\)\({}^{\text{a}}\) & 1.55 \(\pm\) 0.07 \({}^{\text{c}}\) & 2.87 \(\pm\) 0.29 \({}^{\text{b}}\) & 12.59 \(\pm\) 0.19 \\ C18:1 & Oleic acid & \(1.11\pm 0.04\)\({}^{\text{a}}\) & 1.33 \(\pm\) 0.04 \({}^{\text{b}}\) & 7.49 \(\pm\) 0.15 \({}^{\text{c}}\) & 2.55 \(\pm\) 0.09 \\ C18:2 & linoleic acid & \(25.83\pm 0.17\)\({}^{\text{a}}\) & 31.93 \(\pm\) 0.47 \({}^{\text{b}}\) & 33.94 \(\pm\) 0.26 \({}^{\text{c}}\) & 5.89 \(\pm\) 0.11 \\ C18:4 & Stearidonic acid & \(0.19\pm 0.01\)\({}^{\text{a}}\) & 0.82 \(\pm\) 0.14 \({}^{\text{b}}\) & n.a. & n.a. \\ C20:4 & Arachidonic acid & \(0.19\pm 0.01\)\({}^{\text{a}}\) & 0.62 \(\pm\) 0.00 \({}^{\text{b}}\) & n.a. & n.a. \\ C21:5 & Tetracosanolpentaenoic & & & & \\ C21:5 & acid & \(0.74\pm 0.00\)\({}^{\text{a}}\) & 26.82 \(\pm\) 1.19 \({}^{\text{b}}\) & n.a. & n.a. \\ Phytol & & 18.40 \(\pm\) 0.16 \({}^{\text{a}}\) & 28.01 \(\pm\) 2.38 \({}^{\text{b}}\) & 8.83 \(\pm\) 0.28 \({}^{\text{c}}\) & n.a. \\ \(\Sigma\)SFAs & & 41.79 \(\pm\) 0.35 \({}^{\text{a}}\) & 22.91 \(\pm\) 0.40 \({}^{\text{b}}\) & 40.13 \(\pm\) 0.28 \({}^{\text{c}}\) & 66.95 \(\pm\) 0.16 \\ \(\Sigma\)MUFAs & & 12.66 \(\pm\) 0.18 \({}^{\text{a}}\) & 15.05 \(\pm\) 0.40 \({}^{\text{a}}\) & 16.20 \(\pm\) 0.47 \({}^{\text{b}}\) & 13.72 \(\pm\) 0.38 \\ \(\Sigma\)PUFAs & & 26.96 \(\pm\) 0.18 \({}^{\text{a}}\) & 26.96 \(\pm\) 0.18 \({}^{\text{a}}\) & 35.74 \(\pm\) 0.25 \({}^{\text{b}}\) & 5.89 \(\pm\) 0.26 \\ \hline  & & & & & \\ \end{tabular} Note: Results expressed as average \(\pm\) standard deviation. n.a.—non-available, SFAs—saturated fatty acid acids, MUFAs—mononusaturated fatty acids, PUFAs—mononusaturated fatty acids, MAE—microwave-assisted extraction, TE—traditional extraction. Different letters (a–c) indicate significant differences in the results (\(p\leq 0.05\)).  
\end{table} 
Table 1: Average composition (% of area) of fatty acids obtained by traditional and microwave-assisted extractions of cyanobacterial and microalgal biomass (n = 3). Figure 1: Comparison of lipid recovery yields from _Chlorella_ sp., _Arthrospi_ sp., and _Spharospernopsis_ _torques-regime_ using traditional extraction and microwave-assisted extraction obtained by GC–MS (n = 3). Different letters indicate significant differences in the results (\(p\leq 0.05\)). Table 1 shows that the biofuel would be composed of 14 FAs ranging from C10 to C21 with SFAs, MUFAs, and PUFAs accounting for 6, 3, and 5 of the detected compounds. In general, the most abundant FAs in samples were palmitic (C16:0), linoleic (C18:2), and palmitoleic (C16:1) acids, which had significant differences in concentration among the samples. Other FAs found in noticeable concentrations were myristic (C14:0), stearic (C18:0), and oleic (C18:1) acids. Comparison among the classes of FAs revealed that PUFAs were predominant, constituting from 35.74 \(\pm\) 0.25% (_S. torques-regime_) to 26.96 \(\pm\) 0.18% (_Chlorella_ sp.)