## 3 Results
### Growth and Biomass Production of microalgae
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**NaNO\({}_{3}\) umol} & \multicolumn{6}{c}{**NH\({}_{4}\)Cl \(\mu\)mol**} \\ \hline Treatment & N1 & N2 & N3 & N4 & C1 & C2 & C3 & C4 \\ \(\mu\)mol L\({}^{-1}\) [as Salt] & 111.25 & 222.50 & 445.00 & 890.00 & 111.25 & 222.50 & 445.00 & 890.00 \\ \(\mu\)g L\({}^{-1}\) [N] & 18.33 & 36.67 & 73.33 & 146.67 & 29.13 & 58.26 & 116.52 & 233.05 \\ \hline \multicolumn{8}{c}{Parameter estimation of the sigmoidal curve via least squares (SSQ)} \\ \(N_{0}\) (cells mL\({}^{-1}\)) & 507,498 & 416,176 & 505,885 & 457,116 & 473,424 & 439,717 & 485,535 & 426,034 \\ \(r\) (h\({}^{-1}\)) & 0.0304 & 0.0221 & 0.0351 & 0.0275 & 0.0358 & 0.0294 & 0.0367 & 0.0385 \\ \(k\) or Na\({}_{\rm max}\) (cells mL\({}^{-1}\)) & 5,378,478 & 8,360,922 & 9,553,601 & 125,800,306, 5589,747 & 7,700,407 & 7,921,201 & 11,852,018 \\ \% max \(k\) & 43 & 66 & 76 & 100 & 44 & 61 & 63 & 94 \\ \(k/2\) (cells mL\({}^{-1}\)) & 2,689,239 & 4,180,461 & 4,776,801 & 6,290,153 & 2,794,873 & 3,850,203 & 3,960,600 & 5,926,009 \\ \(t_{h/2}\) (hours) & 74 & 134 & 82 & 119 & 67 & 95 & 75 & 86 \\ \hline \multicolumn{8}{c}{Formula estimation of \(\mu\) and _PDT_} \\ \(\mu_{\rm max}\) (h\({}^{-1}\)) & 0.0111 & 0.0125 & 0.0133 & 0.0114 & 0.0117 & 0.0130 & 0.0129 & 0.0118 \\ _PDT_ (hours) & 62.2 & 55.3 & 52.2 & 60.8 & 59.4 & 53.3 & 53.9 & 58.8 \\ \hline \multicolumn{8}{c}{Parameter estimation of an exponential rise to maximum model via non-linear regression (Note \(t\) (days))} \\ \(b\) & 0.343 & 0.114 & 0.241 & 0.122 & 0.277 & 0.173 & 0.295 & 0.145 \\ \(95\%\)Cl \(b\) & 0.264 & 0.064 & 0.087 & 0.040 & 0.173 & 0.080 & 0.135 & 0.044 \\ \(a\) & 4,349,873 & 9,604,878 & 9,306,673 & 15,151,914 & 5,246,430 & 8,220,818 & 7,207,902 & 14,152,484 \\ \(95\%\)Cl \(a\) & 851,406 & 2,393,787 & 1,012,272 & 2,163,674 & 931,908 & 1,363,124 & 902,546 & 1,691,236 \\ \hline \hline \end{tabular} Values represent equations 1 and 2 parameters and therefore describe the whole growth curves.  
\end{table} 
Table 2: Parameter estimations of _Thalassiosira weissflogii_ growth curves with two different nitrogen sources at different concentrations via different models. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**Time (Days)**} \\ \hline  & **NaNO\({}_{3}\) umol** & **3** & **9** & **15** & **18** \\ \hline Protein & 111.25 & 74.7 \(\pm\) 9.5 & 88.5 \(\pm\) 7.1 & 77.5 \(\pm\) 12.7 & 45.2 \(\pm\) 7.7 \\ Protein & 222.50 & 158.9 \(\pm\) 12.0 & 123.7 \(\pm\) 43.4 & 116.6 \(\pm\) 19.1 & 96.27 \(\pm\) 2.5 \\ (\(\mu\)g mg\({}^{-1}\)) & 445 & 325.1 \(\pm\) 63.4 & 200.0 \(\pm\) 24.4 & 183.4 \(\pm\) 2.2 & 144.7 \(\pm\) 7.5 \\  & 890 & 351.4 \(\pm\) 22.8 & 239.7 \(\pm\) 36.5 & 232.9 \(\pm\) 3.6 & 185.6 \(\pm\) 10.5 \\ \hline  & 111.25 & 178.0 \(\pm\) 27.7 & 390.4 \(\pm\) 9.7 & 399.4 \(\pm\) 50.3 & 290.2 \(\pm\) 9.9 \\ Carbohydrates & 222.50 & 188.8 \(\pm\) 70.5 & 386.7 \(\pm\) 10.9 & 312.8 \(\pm\) 48.7 & 436.6 \(\pm\) 5.3 \\ (\(\mu\)g mg\({}^{-1}\)) & 445 & 216.5 \(\pm\) 66.7 & 274.1 \(\pm\) 36.7 & 334.1 \(\pm\) 43.0 & 272.1 \(\pm\) 64.7 \\  & 890 & 215.8 \(\pm\) 15.4 & 253.7 \(\pm\) 10.0 & 238.5 \(\pm\) 7.4 & 211.5 \(\pm\) 5.8 \\ \hline  & 111.25 & 318.6 \(\pm\) 22.0 & 494.5 \(\pm\) 10.5 & 447.1 \(\pm\) 20.9 & 370.1 \(\pm\) 8.7 \\ Lipids & 222.50 & 338.9 \(\pm\) 31.2 & 460.4 \(\pm\) 51.1 & 388.2 \(\pm\) 22.4 & 356.4 \(\pm\) 40.2 \\ (\(\mu\)g mg\({}^{-1}\)) & 445 & 244.8 \(\pm\) 5.7 & 349.1 \(\pm\) 44.2 & 340.3 \(\pm\) 38.7 & 268.5 \(\pm\) 32.8 \\  & 890 & 240.0 \(\pm\) 10.1 & 281.9 \(\pm\) 61.9 & 335.5 \(\pm\) 12.5 & 289.1 \(\pm\) 13.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Total protein, carbohydrate and lipid contents (mean value and standard deviation) of _Thalassiosira weissflogii_ dry biomass at different days, cultured at four different nitrogen concentrations of NaNO\({}_{3}\). \(\mathrm{R}^{2}\) = 0.93 and \(p\) < 0.05, whereas for NH\({}_{4}\)Cl the slope was 2.53 \(\times\) 10\({}^{-8}\) mg cell\({}^{-1}\), \(\mathrm{R}^{2}\) = 0.95 and \(p\) < 0.05.