Microalgal Lipids Production and NitrogenPhosphorus Removal Using the Green Alga Neochloris oleoabundans

A Neochloris oleoabundans strain screened in our lab was demonstrated to have the ability to accumulate large quantities of triglycerides, the feedstock of biodiesel production, and to remove nitrogen and phosphorus from wastewater efficiently. Box-Behnken experimental design (BBD) and response surface method (RSM) were used to study the effects of a large number of nutrients on cell growth and lipid accumulation. The optimized medium supported a lipid concentration of 641.4 mg/l and a cell density of 2.54 g/l, which were 4.5-fold and 2.2-fold of that obtained with the basic medium, modified Bristol medium (MBM), respectively. The capacity of the strain for phosphorus removal and nitrogen removal was investigated using artificial wastewater and municipal wastewater effluents. It was demonstrated that the strain could achieve near-zero residual phosphate and nitrogen at the end of cultivation when artificial wastewater contained up to 140 mg N-NO 3-/l and 47 mg P-PO43-/l. The rates of the removal of N-NO3- and P-PO4 3-, are 27.5 mg/l·d, and 9.4 mg/l·d, respectively under optimal conditions. It was observed that the nitrogen content of the wastewater effluent was not sufficient and additional nitrogen source (e.g., NaNO 3) of 70 mg/l was required for optimal cell growth, CO2 fixation, and phosphate removal