Dunaliella sp. ABRIINW-I1 as a cell factory of nutraceutical fatty acid pattern: An optimization approach to improved production of docosahexaenoic acid (DHA)

[Display omitted] •Dunaliella ABRIINW-I1 produces docosahexaenoic acid comparable to commercial sources.•The fatty acid profile of the isolate shows appropriate health lipid indices.•Production of docosahexaenoic acid is improved by biomass optimization.•Salinity, temperature and light have simultaneous effect on DHA production. The present study aimed to develop a culturing regime directed to achieve an optimal balance of growth with DHA yield by an indigenous DHA producing microalga, Dunaliella sp. ABRIINW-I1. An experimental factorial design with three factors of salinity, temperature, and light each in two levels of 0.5 and 2 M; 15 and 25 ℃, 200 and 1200 μmol photon m−2 s−1 was set up. The results showed that the combinatory effect of salinity, temperature and light was significant on biomass, total fatty acid (TFA) and DHA production. The highest biomass concentration was attained in 0.5 M, 25 ℃, 200 μmol photon m−2 s−1 (604 mg L−1) followed by 0.5 M, 25 ℃, 1200 μmol photon m−2 s−1 (574 mg L−1). The maximal DHA content of 36 % TFA and volumetric production of 30 mg L-1 occurred in 0.5 M, 25 ℃, 1200 μmol photon m−2 s-1. The achieved DHA level of Dunaliella sp. ABRIINW-I1 in its favorable production regime was comparable with those in commercial sources of Thraustochytrids. The studied microalga, generally, due to the high content of DHA, alpha-linolenic acid, n3:n6 ratio and proper lipid health indices might be nominated as a promising biofactory of fatty acids with nutritional value.