## 3 Results
### DHA Production and Fatty Acid Profiles of NCYC4007 Strain  
In raw and analytical grade glycerol, as well as glucose, the _Rhodotorula_ strain NCYC 4007 presents a DHA production between 19% and 23% in ODW (Figure 2a-c). Comparing these three carbon sources, raw glycerol allowed the maximum DHA production at 144 h of cultivation, with a lesser time registered with analytical glycerol and glucose (192 and 216 h, respectively; Figure 2a,b). The results also indicated, at 15 \({}^{\circ}\)C, a significantly higher production of DHA (23% ODW; \(p<0.05\)) when NCYC4007 was cultivated in raw glycerol (Figure 2c) compared to analytical grade glycerol and glucose was obtained. Thus, the DHA production in this strain is consistent from what was observed with respect to the biomass production in all carbon sources tested (Table 1). Given that this strain showed the greatest total DHA production (ODW) at 15 \({}^{\circ}\)C with the three carbon sources used, this was set as the optimum temperature to cultivate and acquire the fatty acid profiles of NCYC  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Culture** & \multicolumn{3}{c}{**B (g)**} & \multicolumn{3}{c}{**\(\mu\) Maximum (h\({}^{-1}\))**} & \multicolumn{3}{c}{**Td (h)**} \\ \cline{2-7}
**Media** & **NCYC4007** & **NCYC1146** & **NCYC4007** & **NCYC1146** & **NCYC4007** & **NCYC1146** \\ \hline SM (15 \({}^{\circ}\)C) & 108 & 97.2 & 0.03 & 0.05 & 23 & 14 \\ SM (21 \({}^{\circ}\)C) & 102 & 91.8 & 0.03 & 0.04 & 23 & 17 \\ SM (31 \({}^{\circ}\)C) & 96 & 86.4 & 0.03 & 0.04 & 23 & 17 \\ AGM (15 \({}^{\circ}\)C) & 126 & 113.4 & 0.03 & 0.05 & 23 & 14 \\ AGM (21 \({}^{\circ}\)C) & 116 & 104.4 & 0.03 & 0.04 & 23 & 17 \\ AGM (31 \({}^{\circ}\)C) & 126 & 113.4 & 0.05 & 0.07 & 14 & 10 \\ RGM (15 \({}^{\circ}\)C) & *152 & *191.8 & *0.08 & *0.11 & *9 & *6 \\ RGM (21 \({}^{\circ}\)C) & 92 & 82.8 & 0.04 & 0.06 & 17 & 12 \\ RGM (31 \({}^{\circ}\)C) & 54 & 48.6 & 0.05 & 0.07 & 14 & 10 \\ \hline \hline \end{tabular}  
* Significant statics value (<0.05).  
\end{table}
Table 1: Kinetic growth parameters of the NCYC 4007 and NCYC 1146 strains obtained by the tested culture media at three different temperatures (15, 21 and 31 \({}^{\circ}\)C). Total biomass production in dry weight (B), maximum growth speed (\(\mu\) maximum) and duplication time (Td).  
Figure 1: Location the NCYC1146 strain on the phylogenetic tree, based on the ribosomal gene 18s rRNA sequence, compared to the marine fungoides sequences described by [PERSON] et al. [9]. To carry out the comparison, the species _Rhodotorula_ sp., _Rhodotorula mucilaginousa, Rhodotorula glutinis, Rhodosporidium diboratum, Schizochytrium_ sp. and _Thraustochytriidae_ sp. were used as representatives for the genus _Rhodotorula_, _Rhodosporidium_, _Schizochytrium_ and _Thraustochytrium_. _Porocentrum mians_ was used as an outgroup. The tree was constructed by the Neighbor-joining (NJ) method and the MEGA 6 program.  
4007 (Table 2). In general terms, the three carbon sources tested showed similar results for this strain, with a greater percentage of unsaturated fatty acids (UFAs) than saturated (SFAs). The high percentage of UFAs was achieved using glucose, followed by AG and RG (Table 2). The fatty acid profiles also showed that the NCYC 4007 strain produces a greater DHA percentage in respect to TFA using glucose (27% of TFA) than in the AG, albeit the DHA concentration (mg g\({}^{-1}\) FDW biomass) obtained with glucose presented no significant differences with RG (Table 2).