A greener and simpler lutein extraction process applied to heterotrophically-grown Scenedesmus almeriensis

In this study, the extraction of lutein from the microalgae Scenedesmus almeriensis cultivated under heterotrophic conditions was investigated with the aim of making the process more environmentally friendly, less toxic for subsequent food and feed usage, and with a reduced ecological footprint. The results show that freeze-drying the biomass does not increase lutein recovery (p > 0.05). Additionally, $$4^{\circ }$$ C storage of wet biomass is a viable alternative (15 % loss) to - $$20^{\circ }$$ C storage. Ethanolic KOH solution was found to be more effective (+32.8 %) for lutein extraction compared to aqueous solution, although saponification ultimately did not provide benefits for lutein extraction. Among the solvents compared, ethanol (0.85 ± 0.01 mg $$\hbox {gDW}^{-1}$$ ) performed as well as acetone (0.91 ± 0.11 mg $$\hbox {gDW}^{-1}$$ ) or isopropanol (0.87 ± 0.01 mg $$\hbox {gDW}^{-1}$$ ) and was better than methanol (0.61 ± 0.01 mg $$\hbox {gDW}^{-1}$$ ) or 2-methyltetrahydrofuran (0.38 ± 0.08 mg $$\hbox {gDW}^{-1}$$ ). In addition, a single bead-beating round allows for the recovery of $$99^+$$ % of the pigments, and the maceration step appears facultative. Ethanolic extracts remained stable at both $$4^{\circ }$$ C and – $$20^{\circ }$$ C for at least one month. All these findings were agglomerated and proposed as a streamlined protocol. Finally, it was observed that cells of S. almeriensis grown under heterotrophic conditions offer less disruption resistance than their autotrophic counterparts.