## 3 Results and Discussions
### Agronomic Trials by Plant Growth and Lixiviation Tests
Table 5 shows different studies from literature data that used microalgal biomass as fertilizer for plants growth. Microalgae has been used as fertilizers for the cultivation of various plants and vegetables such as: tomatoes [25; 43], millet crops [46], corn [26; 27], lettuce [24], cucumber [26], arugula [47] and bayam red [47]. Nonetheless, only one study until yet have reported the use of microalgae cultivated in liquid digestate from biogas plant \begin{table}
\begin{tabular}{c c c c c} \hline  & **C(\%-TS)** & **H(\%-TS)** & **N(\%-TS)** & **S(\%-TS)** \\ \hline
**S** & 38.60 \(\pm\) 0.12 & 5.94 \(\pm\) 0.06 & 0.95 \(\pm\) 0.03 & 0.26 \(\pm\) 0.01 \\ \hline
**SE** & 38.13 \(\pm\) 0.14 & 5.88 \(\pm\) 0.01 & 1.54 \(\pm\) 0.03 & 0.21 \(\pm\) 0.00 \\ \hline
**SD** & 37.76 \(\pm\) 0.03 & 5.87 \(\pm\) 0.03 & 1.45 \(\pm\) 0.03 & 0.28 \(\pm\) 0.01 \\ \hline
**SM** & 38.14 \(\pm\) 0.14 & 5.88 \(\pm\) 0.06 & 1.04 \(\pm\) 0.01 & 0.33 \(\pm\) 0.02 \\ \hline \end{tabular}
\end{table} 
Table 4: Elemental composition of tomato plants cultivated in the following conditions: with no fertilizer (S), synthetic fertilizer (SE), liquid digestate (SD) and microalgal biomass (SM). Given values (\(\pm\)S.D). Figure 4: (a) Germination Index (GI) and dried biomass, (b) leaves numbers and (c) chlorophyll and carotenoids contains obtained in tomato plant grown with the following conditions: S (soil alone, control), SE (soil + synthetic fertilizer), SD (soil + liquid digestate) and SM (soil + microalgal biomass). to be used as fertilizers. In this study, [PERSON] et al. (2005) investigated the use of an algal consortium to be used for the cultivation of cucumber and corn plants ([PERSON] et al., 2015). For the two plants investigated, algae used as fertilizers lead to an enhancement of the growth plant in comparison with no fertilization and similar results were observed between microalgae and synthetic fertilizers ([PERSON] et al., 2015). [PERSON] et al. (2016) studied the potential of cultivating _Spirulina platensis_ with fish wastewater for production of algae fertilizers ([PERSON] et al., 2016). _Spirulina_-based fertilizers demonstrated to enhance plant growth in leafy vegetables such as Bayam red ([PERSON] et al., 2016). The spirulina-based fertilizers enhanced plants growth in comparison with no fertilization and give similar results than synthetic fertilizers (9.06 gTS for _Spirulina_ sp. vs. 9.52 gTS for synthetic fertilizers) ([PERSON] et al., 2016). [PERSON] et al. 2017 studied the effect of algal biomass cultivated in industrial wastewaters on millet crops ([PERSON] et al., 2017). Outdoors experiments were conducted in Brazil during 60 days with three different treatments: control (soil), algal biomass and synthetic fertilizer. As a result, the fertilized soils with microalgae improve the biomass yield of 54% in comparison to the control, in terms of dry biomass (shoot and leaf) obtained per hectare. Furthermore, no significant differences were found between soils fertilized with algal biomass and synthetic fertilizer ([PERSON] et al., 2017). Finally, [PERSON] and [PERSON] (2015) also investigated the effect of microalgae (_Acutodesmus dimorphus LARB-0414_) fertilizers on the tomatoes growth ([PERSON] et al., 2015). Microalgae were applied at the transplantation or 22 days prior the transplantation of tomatoes plants. Both configurations improve the tomatoes growth in comparison with the control without fertilization. Nonetheless, applying microalgae 22 days prior transplantation at a concentration of 50 g lead to an enhancement of the biomass production. Indeed biomass production of 153 g and 547 g were respectively noticed for the fertilization at the time of transplant and 22 days prior the time of transplant ([PERSON] et al., 2015). \begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline
**Modition Control and First-Item Used** & **Missing Selection** & **Oos Type** & **Random Application** & **Classification Conditions** & **Teamored Heart Glucose-Harvey Framework Compared to Control** & **Ref. ** \\ \hline \hline \