Production of metabolites from Scenedesmus sp. and a microalgal consortium cultured in unconventional media

Abstract

Growth comparisons were made between a microalgal consortium and Scenedesmus sp. cultivated in treated wastewater (TWw) enriched with 1 mL·L–1 Bayfolan Forte fertilizer (BM), TWw enriched with (NH4)2HPO4 (PAM), TWw enriched with NH4HCO3 (BCAM), tap water with piggery wastewater (PEM), tap water with piggery wastewater digestate (PDM), and raw wastewater (Ww). Nitrogen (N) content in the media, except for TWw, was adjusted to 80 mg·L–1 N (NH4+-N and NO3–-N). Unconventional low-cost media with lower nutrient contents (BM and TWw) showed adequate productions of biomass and lipids. PEM was the most advantageous medium, showing the highest biomass productivity with the consortium (191.25 ± 6.25 g·L–1·d–1) and a lipid productivity of 36.75 ± 9.90 mg·L–1·d–1. The fatty acid profile was composed mainly of C16 and C18. PAM, PEM, and PDM showed a higher proportion of saturated fatty acids (60%–69%), whereas the composition of unsaturated fatty acids was in the range of 31% to 38%. In PEM and PDM the removal of NH4+ was 100%; however, there were NH4+ losses (as NH3) due to volatilization (46%). Unconventional media, especially Ww, are an option for growing microalgae.