Biosynthesis of microalgal lipids, proteins, lutein, and carbohydrates using fish farming wastewater and forest biomass under photoautotrophic and heterotrophic cultivation.

[Display omitted] • Chlorella sorokiniana cultivation under photoautotrophic or heterotrophic conditions. • Higher lipids (3.19 ± 0.23 g/L) at C/N 60 after 72 h growth on heterotrophic mode. • Autotrophic cultivation favored proteins (416.66 mg/g CDW) & lutein (6.40 mg/g CDW) • Total Carbohydrates for photoautotrophic (6.39 %) and heterotrophic (8.66 %) modes. • The lipid profile was suitable for its application in biodiesel production. Biorefineries enable the circular, sustainable, and economic use of waste resources if value-added products can be recovered from all the generated fractions at a large-scale. In the present studies the comparison and assessment for the production of value-added compounds (e.g., proteins, lutein, and lipids) by the microalga Chlorella sorokiniana grown under photoautotrophic or heterotrophic conditions was performed. Photoautotrophic cultivation generated little biomass and lipids, but abundant proteins (416.66 mg/g CDW) and lutein (6.40 mg/g CDW). Heterotrophic conditions using spruce hydrolysate as a carbon source favored biomass (8.71 g/L at C/N 20 and 8.28 g/L at C/N 60) and lipid synthesis (2.79 g/L at C/N 20 and 3.61 g/L at C/N 60) after 72 h of cultivation. Therefore, heterotrophic cultivation of microalgae using spruce hydrolysate instead of glucose offers a suitable biorefinery concept at large-scale for biodiesel-grade lipids production, whereas photoautotrophic bioreactors are recommended for sustainable protein and lutein biosynthesis. [ABSTRACT FROM AUTHOR]