## 3 Results and Discussion
### Nutritional Composition of the Microalgae Biomass  
The cultivation conditions of the seven microalgae species were largely comparable. Except for _Limospira_ sp., the pH remained within the range of 7-8 for all species. Temperature fluctuations ranged from below 20 \({}^{\circ}\)C to 30.3 \(\pm\) 1.6 \({}^{\circ}\)C. The photosynthetically active radiation (PAR) varied from 10.8 \(\pm\) 3.15 to 46.0 \(\pm\) 6.89 mol/m\({}^{2}\)/day, with all values of similar magnitude and yielding a mean of 33.7 mol/m\({}^{2}\)/day (Table 1). Despite these variation in cultivation conditions, all biomass samples were characterized with respect to their moisture, ash, lipid, protein, fiber, and carbohydrate content. Protein was the predominant macronutrient in the biomass, ranging from 22.9 \(\pm\) 0.1% to 59.8 \(\pm\) 1.6% dry weight (DW) across the different microalgae species (Table 3 and Figure 2). Under the cultivation conditions outlined in Section 2.1, _Limospira_ sp. exhibited \begin{table}
\begin{tabular}{c c c c c c} \hline
**Microalgae** & \(L^{*}\) & \(a^{*}\) & \(b^{*}\) & **Hue (\({}^{\circ}\))** & **C*** \\
**Species** & & & & & \\ \hline _Limnospira_ sp. & 8.78 \(\pm\) 0.47 \({}^{\rm c}\) & \(-\)1.88 \(\pm\) 0.26 \({}^{\rm d}\) & 3.20 \(\pm\) 0.21 \({}^{\rm e}\) & \(-\)59.8 \(\pm\) 2.5 \({}^{\rm c}\) & 3.71 \(\pm\) 0.31 \({}^{\rm f}\) \\ _Dunialella_ sp. & 8.55 \(\pm\) 1.34 \({}^{\rm c}\) & \(-\)1.15 \(\pm\) 0.18 \({}^{\rm c}\) & 2.78 \(\pm\) 0.48 \({}^{\rm f}\) & \(-\)67.4 \(\pm\) 1.7 \({}^{\rm e}\) & 3.01 \(\pm\) 0.50 \({}^{\rm g}\) \\ _Lobosphaera_ sp. & 18.27 \(\pm\) 0.63 \({}^{\rm a}\) & \(-\)9.63 \(\pm\) 0.19 \({}^{\rm e}\) & 11.96 \(\pm\) 0.25 \({}^{\rm a}\) & \(-\)51.17 \(\pm\) 0.10 \({}^{\rm b}\) & 15.36 \(\pm\) 0.31 \({}^{\rm a}\) \\ _Nannochloropsis_ sp. & 13.07 \(\pm\) 2.37 \({}^{\rm b}\) & \(-\)0.43 \(\pm\) 0.11 \({}^{\rm b}\) & 7.73 \(\pm\) 0.72 \({}^{\rm b}\) & \(-\)86.8 \(\pm\) 0.9 \({}^{\rm f}\) & 7.74 \(\pm\) 0.72 \({}^{\rm c}\) \\ _Odontella_ sp. & 13.51 \(\pm\) 1.17 \({}^{\rm b}\) & \(-\)0.47 \(\pm\) 0.06 \({}^{\rm b}\) & 5.23 \(\pm\) 0.18 \({}^{\rm c}\) & \(-\)84.9 \(\pm\) 0.8 \({}^{\rm f}\) & 5.25 \(\pm\) 0.18 \({}^{\rm d}\) \\ _Porphyridium_ sp. & 9.35 \(\pm\) 0.87 \({}^{\rm c}\) & 8.09 \(\pm\) 0.40 \({}^{\rm a}\) & 3.85 \(\pm\) 0.24 \({}^{\rm d}\) & 25.48 \(\pm\) 2.36 \({}^{\rm a}\) & 8.97 \(\pm\) 0.29 \({}^{\rm b}\) \\ _Tetraselmis_ sp. & 9.14 \(\pm\) 1.66 \({}^{\rm c}\) & \(-\)2.01 \(\pm\) 0.11 \({}^{\rm d}\) & 3.78 \(\pm\) 0.18 \({}^{\rm d}\) & \(-\)62.0 \(\pm\) 1.7 \({}^{\rm d}\) & 4.28 \(\pm\) 0.16 \({}^{\rm e}\) \\ \hline \end{tabular} Different letters in each column mean significant differences (\(p<0.05\)). Three replicates.  
\end{table} 
Table 2: Color parameters of the microalgae biomass. the highest protein content, while _Nannochloropsis_ sp. recorded the highest lipid content. _Lobosphaera_ sp., _Nannochloropsis_ sp., and _Tetraselmis_ sp. were particularly rich in fiber (Table 3). [PERSON] et al. [39] reported that _Linnospira platensis_ biomass contained 53.75 g/100 g DW protein, 7.8 g/100 g DW total lipids, and 9.21 g/100 g DW crude fiber, which are values comparable to those found in the present study (Table 3). [PERSON] et al. [40] analyzed wet biomass of _Dunaliella_ sp. and obtained values of 10.03 \(\pm\) 0.57% (\(w\)/\(w\), dry basis) for protein, 25.31 \(\pm\) 1.55% carbohydrates, 3.49 \(\pm\) 0.10% lipids, and 8.97 \(\pm\) 0.50% total dietary fiber. These results are lower than those in the present study (Table 3). [PERSON] et al. [41], in their evaluation of various microalgal species as potential feed ingredients for aquaculture, found that _Nannochloropsis gaditana_ had the highest protein content, up to 52%, which exceeds the 22.9 \(\pm\) 0.1% observed in this study. Additionally, _Porphyridium crucutum_ was reported to have high carbohydrate (40-57%) and lipids (18%) contents, both higher than the corresponding values obtained here (Table 3).