# Static Magnetic Fields Effects on Polysaccharides Production by Different Microsalgae Strains
## 3 Results  
### Polysaccharides in Chlorella Microalgae Biomass  
The biomass concentration reached 2.30 g L\({}^{-1}\) (Table 1) when C. _fusca_ was cultured outdoor under SMF 24 h, 24% higher than control (1.75 g L\({}^{-1}\)). When SMF was applied for 1 h d\({}^{-1}\), no positive effect on cell growth was noticed, since microalgal growth was similar to the control assay and biomass concentrations showed no significant difference (_p_\(\geq\) 0.05) at all culture times. However, positive effect was noticed for indoor assays, with a 70% increase when SMF was applied for 1 h d\({}^{-1}\) and 85% when SMF was applied for 24 h, compared to control (0.80 g L\({}^{-1}\)). Concerning total carbohydrates, and contrary to what was previously observed for _Spirulina_[16; 35], only a slight increase was noticed for the cultures conducted with SMF and the statistical analysis revealed no significant difference. The more influent factor on the total carbohydrate content was found to be the indoor vs. outdoor condition, as a significant increase was observed for outdoor cultivation. According to [PERSON] [53], an increase in carbohydrate content is observed with high light intensities, due to more efficient carbon fixation through photosynthesis. In the present study, the outdoor assays were carried out with daytime sunlight (300 \(\mu_{\text{molphotons}}\)m\({}^{-2}\) s\({}^{-1}\)), while indoor assays illuminated with daylight-type lamps (100 \(\mu_{\text{molphotons}}\)m\({}^{-2}\) s\({}^{-1}\)). Thus, our results are in accordance with this assumption. In Chlorophyceaeae, like _Chlorella fusca_, the major polysaccharides that can be encountered are the storage polysaccharide (starch, [7]), and those constituting the cell wall \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Assays**} & **Starch (g 100 g\({}^{-1}\))** &
\begin{tabular}{c} **Carbohydrates** \\ **(g 100 g\({}^{-1}\))** \\ \end{tabular} & \(\mathbf{X_{max}}\) **(g L\({}^{-1}\))** \\ \hline \multirow{3}{*}{Indoor} & Control & 6.42 \(\pm\) 0.26 \({}^{\text{a}}\) & 24.84 \(\pm\) 0.11 \({}^{\text{d}}\) & 0.80 \(\pm\) 0.01 \({}^{\text{d}}\) \\  & SMF 1 h d\({}^{-1}\) & 7.28 \(\pm\) 0.61 \({}^{\text{a,b}}\) & 24.98 \(\pm\) 1.00 \({}^{\text{d}}\) & 1.36 \(\pm\) 011 \({}^{\text{c}}\) \\  & SMF 24 h d\({}^{-1}\) & 7.91 \(\pm\) 0.29 \({}^{\text{b}}\) & 27.53 \(\pm\) 0.52 \({}^{\text{c}}\) & 1.48 \(\pm\) 0.11 \({}^{\text{c}}\) \\ \hline \multirow{3}{*}{Outdoor} & Control 1 h d\({}^{-1}\) & 9.67 \(\pm\) 0.82 \({}^{\text{c}}\) & 31.38 \(\pm\) 0.28 \({}^{\text{a,b}}\) & 2.18 \(\pm\) 0.02 \({}^{\text{a}}\) \\  & SMF 1 h d\({}^{-1}\) & 10.94 \(\pm\) 0.55 \({}^{\text{d}}\) & 34.18 \(\pm\) 0.68 \({}^{\text{a}}\) & 2.23 \(\pm\) 0.07 \({}^{\text{a}}\) \\ \cline{1-1}  & Control 24 h d\({}^{-1}\) & 10.12 \(\pm\) 1.27 \({}^{\text{c,d}}\) & 29.16 \(\pm\) 1.38 \({}^{\text{b,c}}\) & 1.75 \(\pm\) 0.03 \({}^{\text{b}}\) \\ \cline{1-1}  & SMF 24 h d\({}^{-1}\) & 10.08 \(\pm\) 0.22 \({}^{\text{c,d}}\) & 31.45 \(\pm\) 0.76 \({}^{\text{a,b}}\) & 2.30 \(\pm\) 0.20 \({}^{\text{a}}\) \\ \hline \hline \end{tabular}  
* Means \(\pm\) standard deviations. Different letters in the same column correspond to significant differences (_p_\(\leq\) 0.05).  
\end{table} 
Table 1: Final biomass concentration (Xmax), total carbohydrates and starch contents in _Chlorella fusca_ LEB 111 biomass cultivated under different conditions of static magnetic field (SMF) application. (cellulose-like, [54]). A few studies have also described EPS released in the culture medium for some _Chlorella_ species, but at really low yield [37; 55]. In our study, we quantified the starch content in each cultivation condition, in order to highlight a potential modulation of the polysaccharide repartition. For the outdoor assays, in both control and SMF application conditions, starch content was found greater than in indoor conditions (\(p\leq 0.05\)). This result seems consistent with the increase of the photosynthesis rate with higher light intensity, as the storage polysaccharide may act as a carbon sink.