Stimulating biolipid production from the novel alga Ankistrodesmus sp. by coupling salt stress and chemical induction

In the present research, the freshwater green alga Ankistrodesmus sp. EHY was isolated from Erhai Lake. To obtain high productivity of biomass and lipids, a joint strategy comprising salinity stress and chemical induction and two-stage cultivation was developed to improve the production of lipids. Coupling salinity stress and gamma-aminobutyric acid (GABA) or CaCl2 addition increased the lipid content to 56.47 ± 1.56% or 59.52 ± 0.00%, which was 1.24 or 1.31 times greater than that of the control, respectively (p < 0.05). The maximum energy yield was achieved under GABA and salt stress conditions of 95.78 kJ L−1. Further data revealed that the combined application of salt stress and GABA or CaCl2 increased the levels of cellular reactive oxidative species (ROS) and lipogenesis genes, accompanied by a further increase in lipids. The quality of the algal lipid-derived biodiesel was within the biodiesel quality ranges for advanced commercial standards. These results suggest that combined application of GABA or CaCl2 and salt stress can stimulate microalgae biolipid synthesis for the production of renewable biodiesel. This work proposes an efficient potential biotechnological method for biolipid production by a novel Ankistrodesmus sp. strain via combined induction of chemical and salt stress under two-stage cultivation.