NaCl as an effective inducer for lipid accumulation in freshwater microalgae Desmodesmus abundans

In order to evaluate the efficiency and potential of salt addition-based two-stage cultivation technology, on the basis of urea as nitrogen source, we compared four types of salts (NaCl, NaHCO3, NaS2O3 and NaAc) as inducers for lipid production in Desmodesmus abundans. The maximum biomass productivity (270.08 mg L−1 d−1) was obtained by using 0.25 g L−1 urea. The highest lipid productivity (67.08 mg L−1 d−1) and better biodiesel quality were realized by addition of 20 g L−1 NaCl, and the optimal time point for salt addition was determined at 1.79 g L−1 of biomass density. Further cost analysis demonstrated this cultivation process was relatively economical. Above results suggest that NaCl addition is an economical and applicable strategy for lipid enhancement and can be extended for microalgae-based biodiesel production.