## 3 Results and Discussion
### Single-Cell Oil (SCO)
#### 3.4.4 Biodiesel Properties
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{4}{c}{_C. curvatus_} & \multicolumn{4}{c}{**Standard Fuel Parameters**} \\ \hline  & **60 g/L GC** & **60 g/L C2** & **40 g/L C3** & **40 g/L C4** & **BSG VFAs** & **ASTM** & **EN 14214** \\  & **(C/N100)** & **(C/N100)** & **40 g/L** & **40 g/L C4** & **BSG VFAs** & **ASTM** & **EN 14214** \\ \hline DU & 73.371 & 71.531 & 60.848 & 87.074 & 70.298 & - & - \\ SV & 198.115 & 199.814 & 182.656 & 200.917 & 182.257 & - & - \\ IV & 68.180 & 68.094 & 60.551 & 81.037 & 65.153 & - & 120 (Max) \\ CN & 58.509 & 58.294 & 62.557 & 55.232 & 61.587 & 47 (Min) & 51 (Min) \\ LCSF & 16.626 & 20.088 & 9.752 & 15.717 & 19.548 & - & - \\ CFPP & 35.758 & 46.635 & 14.161 & 32.901 & 44.936 & country specific \\ CP & 4.295 & 3.894 & 1.490 & 4.615 & 2.114 & country specific \\ PP & \(-\)2.158 & \(-\)2.594 & \(-\)5.204 & \(-\)1.811 & \(-\)4.526 & - & - \\ APE & 73.371 & 71.531 & 60.848 & 87.074 & 70.298 & - & - \\ BAPE & 17.442 & 20.905 & 31.535 & 28.623 & 19.235 & - & - \\ OS & 11.048 & 10.166 & 7.200 & 7.121 & 9.375 & \(\geq\)3 & \(\geq\)6 \\ HHV & 39.079 & 39.526 & 35.423 & 39.565 & 36.278 & - & - \\ \(\upsilon\) & 4.063 & 4.160 & 3.460 & 4.034 & 3.726 & 1.9–6 & 3.5–5.0 \\ \(\rho\) & 0.861 & 0.871 & 0.783 & 0.874 & 0.799 & 0.88 & 0.86–0.9 \\ \hline  & \multicolumn{4}{c}{_R. toruloides_} & \multicolumn{4}{c}{**Standard Fuel Parameters**} \\ \hline  & **GC 30 g/L** & **C2 30 g/L** & **C3 10 g/L** & **C4 10 g/L** & **BSG VFAs** & **ASTM** & **EN 14214** \\  & **(CN100)** & **(CN100)** & **C3 10 g/L** & **C4 10 g/L** & **BSG VFAs** & **ASTM** & **EN 14214** \\ \hline DU & 74.995 & 70.438 & 50.568 & 73.648 & 81.704 & - & - \\ SV & 201.314 & 201.159 & 188.023 & 203.134 & 177.267 & - & - \\ IV & 70.096 & 65.011 & 50.754 & 68.703 & 73.678 & - & 120 (Max) \\ CN & 57.640 & 58.805 & 63.909 & 57.711 & 60.512 & 47 (Min) & 51 (Min) \\ LCSF & 11.408 & 15.082 & 11.203 & 15.708 & 13.279 & - & - \\ CFPP & 19.364 & 30.905 & 18.720 & 32.873 & 25.241 & country specific \\ CP & 6.354 & 4.243 & 10.685 & 10.058 & \(-\)0.097 & country specific \\ PP & 0.077 & \(-\)2.215 & 4.778 & 4.097 & \(-\)6.926 & - & - \\ APE & 74.051 & 70.077 & 50.568 & 73.648 & 81.704 & - & - \\ BAPE & 17.520 & 14.717 & 26.855 & 23.962 & 16.014 & - & - \\ OS & 11.066 & 13.745 & 8.089 & 8.053 & 9.955 & \(\geq\)3 & \(\geq\)6 \\ HHV & 39.191 & 39.506 & 35.910 & 39.523 & 35.400 & - & - \\ \(\upsilon\) & 3.964 & 4.116 & 3.494 & 4.022 & 3.563 & 1.9–6 & 3.5–5.0 \\ \(\rho\) & 0.866 & 0.871 & 0.794 & 0.873 & 0.781 & 0.88 & 0.86–0.9 \\ \hline  & \multicolumn{4}{c}{_SFA, saturated fatty acids (\%); MUFA, monounsaturated fatty acids (\%); PUFA, polyunsaturated fatty acids (\%); DU, degree of unsaturation; SV, sapnicification value (mg/g); IV, iodine value; CN, cetane number; LCSF, long-chain saturation factor; CFPP, cold filter plugging point (\({}^{\circ}\)C); CP, cloud point (\({}^{\circ}\)C); PP, point point (\({}^{\circ}\)C); APE, allylic position equivalent; BAPE, bis-allyic position equivalent; OS, oxidation stability (\({\rm{H}}\)); HHV, higher heating value; \(\upsilon\), kinematic viscosity (mm\({}^{2}\)/s); \(\rho\), density (g/cm\({}^{2}\)). Min, minimum; Max, maximum; -, no standard limit designated by ASTM D6751-02 and EN 14,214 biodiesel standards._ \\ \hline  & & & & & & \\ \end{tabular}
\end{table} 
Table 4: Biodiesel properties of the SCO produced by _C. curvatus_ and _R. toruloides_ and comparison to the standard fuel parameters, ASTM D6751-02 and EN 14,214.  
located directly between two double bonds) sites are easily oxidized [65; 66; 68]. It has been also suggested that oxidative stability is more closely related to the total number of bis allylic sites, rather than the total number of double bonds [69]. The biodiesel produced by both yeasts and for all the tested conditions fulfill the established requirements by both standards regarding the oxidative stability values, with the highest values being 13.7 h for _R. toruloides_ and 10.2 h for _C.