Potential for Carotenoid and Other Bioproducts Production by a Brazilian Dunaliella salina Isolate Using a High Photon Flux Density Strategy.

Dunaliella species are among the most significant biological sources of carotenoids, notably beta-carotene. Given that chemical synthesis offers a more cost-effective alternative to biotechnological cultivation, optimizing production strategies is essential for economic viability. This study investigated the optimization of bioproduct synthesis in a Brazilian strain of Dunaliella salina by evaluating the effects of high photon flux density (PFD) and temperature under low-salinity conditions (1 mol L-1 NaCl) to facilitate downstream processing. Batch cultivations were conducted at 26°C across a PFD gradient ranging from 100 to 2000 µmol photons m-2 s-1, with additional cultivations performed at 30°C under maximum irradiance. The results demonstrated that increasing PFD to 2000 µmol photons m-2 s-1 significantly enhanced metabolic performance, yielding a 25% increase in biomass concentration, a 62% rise in biomass productivity, and an 82% surge in total carotenoid production. Furthermore, carbohydrate content increased by 61%, whereas lipid levels remained stable, exhibiting a fatty acid profile conducive to biodiesel production. The temperature variation up to 30°C had no effect on biomass concentration or biomass composition, affecting only the fatty acid composition. These findings underscore the robust potential of this strain for the large-scale biotechnological production of carotenoids and other high-value compounds within a biorefinery framework.