Effects of Fe3+ on the biomass production, lipid accumulation of Monoraphidium sp. FXY-10 were investigated. Further residual Fe3+ in the culture medium on the sedimentation efficiency have been also studied. The biomass and lipid productivity of microalgae exhibited an increasing tendency with the concentrations of iron ion augmenting. 150 mu M iron ion added into the culture medium result in highest DCW at 1.42 g L-1 while the maximum lipid productivity of 10.71 mg L-1 d(-1) were obtained at 50 mu M. The results showed that appropriate concentrations of iron ion was beneficial for biomass production and lipid accumulation but higher concentration of that will be more in favor of the sedimentation efficiency of Monoraphidium sp. FXY-10. (C) 2015 Elsevier Ltd. All rights reserved.