Comparison of selenium-induced antioxidant responses and bioaccumulation in two strains of the halotolerant alga Dunaliella salina

Abstract

Abstract Selenium water pollution is an increasing environmental problem that requires investigation of cellular responses of aquatic primary producer organisms, especially algae. Industrial wastewater with selenium contamination is often coupled with high salinity (60–70). In this study, the biochemical responses of two strains of the halotolerant alga (Dunaliella salina Hoze-soltan and Dunaliella salina CCAP 19/18) to different selenium concentrations were evaluated. Although at high selenium concentrations both strains showed lipid peroxidation and cell number reduction, Dunaliella salina Hoze-soltan was less affected. Higher selenium tolerance in this strain might be attributed to the better activity of resistance responses like proline, total reducing sugar, superoxide dismutase (SOD) and peroxidase (POX), even at the high selenium concentrations. Catalase (CAT) had no significant role for protection against selenium toxicity as its activity declined in both strains with rising selenium concentration. Both strains accumulated selenium intracellularly, but the accumulation was about three-fold higher in Dunaliella salina Hoze-soltan than in the other strain. It can be concluded that Dunaliella salina Hoze-soltan may be a better candidate for selenium bioremediation of a high salinity environment. The data obtained from this study could be useful for improvement of algal ability for high efficiency selenium bioremediation in hypersaline environments.