Effect of ferric ion on nitrogen consumption, biomass and oil accumulation of a Scenedesmus rubescens-like microalga

This investigation examined the effects of ferric ion source and concentration on the biomass yield, fatty acid methyl esters (FAME) productivity and composition from Scenedesmus rubescens-like microalga. The algae cultivated with Fe 2 + – SO 4 2 - /EDTA had higher ash free dry biomass (AFDB) production and in vivo chlorophyll a concentration than those with Fe 2 + – SO 4 2 - and Fe3+–Cl− (P < 0.001). The high or low Fe2+ concentration can partly restrict the ammonia consumption, the AFDB and FAME accumulation. The algae at 1 mg/L Fe2+ concentration had the highest AFDB and FAME productivity (341.1 ± 25.8 and 107.8 ± 19.3 mg/L/d) (P < 0.001). The mean content of C16 and C18 series at all Fe2+ concentrations was 88.6% ± 2.9% of total FAME, and it decreased with the increase of Fe2+ concentrations. Among the fatty acids profiles, the contents of C18: 0, C18: 1n−7 and C18: 1n−9 are significantly changed under the different Fe2+ concentrations, but not the contents of C16 series.