Salinity induced oxidative stress alters the physiological responses and improves the biofuel potential of green microalgae Acutodesmus dimorphus

•Salinity induced oxidative stress improved the biofuel potential of A. dimorphus.•Addition of 200mM NaCl increased the lipid and carbohydrate accumulations over 50%.•Salinity stress of 200mM for 2days increased the biomass of A. dimorphus.•Oxidative stress biomarkers were the lowest in 2days stressed culture.•3days of stress increased lipid accumulation by 43% without affecting the biomass. The main aim of the present study was to analyze salinity stress induced physiological and biochemical changes in a freshwater microalgae Acutodesmus dimorphus. During single-stage cultivation, the accumulations of lipids and carbohydrates increased with an increase in an initial salinity of the culture medium. The carbohydrate and lipid accumulations of 53.30±2.76% and 33.40±2.29%, respectively, were observed in 200mM NaCl added culture. During two-stage cultivation, salinity stress of 200mM was favorable for the growth up to 2days, as suggested by higher biomass, lower levels of oxidative stress biomarkers and no significant changes in the biochemical composition of the cells. Extending the stress to 3days significantly increased the lipid accumulation by 43% without affecting the biomass production. This study, thus, provides the strategy to improve the biofuel potential of A. dimorphus along with presenting the physiological adaptive mechanisms of a cell against salinity stress.