Exploration of two-stage cultivation strategy using nitrogen limited and phosphorus sufficient to simultaneously improve the biomass and lipid productivity in Desmodesmus intermedius Z8

In this work, the effects of nine different nitrogen and phosphorus conditions on the growth and lipid production of Desmodesmus intermedius Z8 were investigated. The highest lipid concentration of 0.89 g center dot L-1 was obtained at 6 days under the Nlim&P (nitrogen limited and phosphorus sufficient) condition. To further enhance the total lipid production, the two-stage cultivation strategy was performed. The results show that the addition of 750.0 mg center dot L-1 of nitrogen and 40.00 mg center dot L-1 of phosphorus at the end of the second day of incubation could effectively improve the lipid productivity. Under this condition, they could reach 244.69 mg center dot(L center dot d)-1, which was 1.66-folds higher than that of the control group. Furthermore, the fatty acid composition analysis indicates that the lipid could meet the standards of biodiesel. Therefore, the two-stage regulation strategy, according to the results in this study, is an effective and simple method to realize high lipid production and quality, and then showing its po-tential for biodiesel production.