Augmentation of arsenic enhances lipid yield and defense responses in alga Nannochloropsis sp.

•Nannochloropsis sp. illustrates high capacity of biodiesel production.•FA profile and lipid productivity credited alga as an excellent energy resource.•Nannochloropsis sp. exhibited terrific tolerance against arsenic at 100 μM As(III).•Nannochloropsis sp. accumulated maximum 2019.04 μg/g dw As.

The present study was conducted with microalga Nannochloropsis sp. to evaluate its tolerance responses and biofuel perspectives under different arsenic regime (0-1000 μM As(III)). Results showed that optimal biomass (61.00 ± 3.72 mg/L/d) and lipid productivity (20.27 mg/L/d) were obtained in culture treated with 100 μM As(III) in comparison to other treatments. In addition, fatty acid profile of alga was in accordance with European biodiesel standards (EN 14214), which reflects good oxidative stability of oil. High antioxidants viz., ascorbic acid, GSH and cysteine tolerance responses as well as lipid yield at 100 μM As(III), opens a new insight in the field of algal biology. Thus, microalgae Nannochloropsis sp. may be employ in remediation as well as biodiesel production.