## 3 Results
### Chemical Content in Diatoms with and without Future  
The lipid content of our diatoms cultivated with or without factory flue gas is shown in Table 7. The addition of flue gas to the cultivation did not affect the accumulation of lipids in this experiment, and both treatments contained approximately 10% lipids of freeze dried weight, corresponding to approximately 20% lipids of ash-free dry weight. Some differences in the fatty acid composition with or without factory smoke were observed (Table 8). Notably, the total omega-3 content was slightly higher in the samples cultivated with factory flue gas; this difference was due to an elevated content of 18:4n-3. The eicosapentaenoic acid (EPA, 20:5n-3) was similar in both samples. Samples without factory flume appeared to upregulate the synthesis of 16:4n-1 compared to the other treatment, which resulted in a similar total amount of polyunsaturated fatty acids in both sample treatments. \begin{table}
\begin{tabular}{c c c c c} \hline  & **Mean** & **+/\(-\)S.D.** & **n** & **Unit** \\ \hline CO\({}_{2}\) uptake & 26.45 & 8.85 & - & \% \\ Uptake NO\({}_{3}\)\({}^{-}\) + NO\({}_{2}\)\({}^{-}\) in diatoms \({}^{*}\) & 110.54 & 146.9 & 117 & \(\mu\)mol cm\({}^{3}\) \\ Uptake PO4\({}^{-}\) in diatoms \({}^{*}\) & 20.15 & 19.37 & 127 & \(\mu\)mol cm\({}^{3}\) \\ Uptake SiO\({}_{2}\)\({}^{-}\) in diatoms \({}^{*}\) & 47.70 & 67.46 & 96 & \(\mu\)mol cm\({}^{3}\) \\ Light utilization efficiency & 21.66 & 22.71 & 84 & \% (W vs. W) \\ Temperature in reactor & 6.64 & 5.07 & 852 & \({}^{\circ}\)C \\ pH & 8.089 & 0.41 & 679 & \\ Biovolume with cells \(<\) 30 \(\mu\)m ** & 0.189 & 0.151 & 152 & cm\({}^{3}\) \\ Biovolume with cells \(>\) 30 \(\mu\)m ** & 0.622 & 0.205 & 102 & cm\({}^{3}\) \\ Production with cells \(<\) 30 \(\mu\)m ** & 0.219 & 0.327 & 102 & cm\({}^{3}\) L\({}^{-1}\) Day\({}^{-1}\) \\ Production with cells \(>\) 30 \(\mu\)m ** & 0.260 & 0.139 & 102 & cm\({}^{3}\) L\({}^{-1}\) Day\({}^{-1}\) \\ \hline \end{tabular} \({}^{*}\) Biomass (cm\({}^{3}\) biovolume) specific uptake; ** Cultivations performed with approximately same reactor illuminations.  
\end{table} 
Table 6: Operating results from cultivation in the 300,000 L reactor 2018–2021. Figure 15: Harvested biovolume from the 300,000 L reactor vs. wet weight of the same harvested biomass, r = 0.61 at \(p<\) 0.05 and n = 60. All amino acids, except aspartic acid and arginine, presented higher values when cultivated with factory fume addition than with air (Table 9). The total DW specific amino acid content was therefore 34% vs. 30% weight based, with and without fume, respectively. The relative portion of EAA was though comparable, i.e., 36-37%. \begin{table}
\begin{tabular}{c c c} \hline  & **With Flue Gas** & **Without Flue Gas** \\ \hline C14:0 & 9.6 \(\pm\) 0.16 & 6.8 \(\pm\) 0.29 \\ C16:0 & 5.7 \(\pm\) 0.01 & 6.4 \(\pm\) 0.05 \\ C16:1 n-7 & 8.4 \(\pm\) 0.04 & 9.9 \(\pm\) 0.06 \\ C16:3n-4 & 13.9 \(\pm\) 0.06 & 12.7 \(\pm\) 0.03 \\ C18:0 & 0.3 \(\pm\) 0.02 & 0.1 \(\pm\) 0.13 \\ C16:4n-1 & 15.6 \(\pm\) 0.06 & 21.6 \(\pm\) 0.04 \\ C18:2 n-6 & 0.3 \(\pm\) 0.00 & 0.0 \(\pm\) 0.00 \\ C20:0 & 0.1 \(\pm\) 0.13 & 0.3 \(\pm\) 0.01 \\ C18:4 n-3 & 9.4 \(\pm\) 0.05 & 4.5 \(\pm\) 0.01 \\ C22:1 n-11 & 0.3 \(\pm\) 0.01 & 0.0 \(\pm\) 0.00 \\ C20:5 n-3 & 32.6 \(\pm\) 0.19 & 32.8 \(\pm\) 0.27 \\ C22:6 n-3 & 3.7 \(\pm\) 0.04 & 4.7 \(\pm\) 0.06 \\ \(\Sigma\)SFA & 15.7 \(\pm\) 0.17 & 13.7 \(\pm\) 0.33 \\ \(\Sigma\)MUFA & 8.6 \(\pm\) 0.05 & 9.9 \(\pm\) 0.06 \\ \(\Sigma\)PUFA & 75.7 \(\pm\) 0.17 & 76.4 \(\pm\) 0.36 \\ \(\Sigma\)Omega-3 & 45.8 \(\pm\) 0.26 & 42.1 \(\pm\) 0.33 \\ \hline \end{tabular}
\end{table} 
Table 8: Fatty acid composition (%, average \(\pm\) SD, n = 5) of the diatom cultivated with and without factory flue gas.