Phytosterols from Dunaliella tertiolecta and Dunaliella salina: A potentially novel industrial application

Sterols have been extracted and analysed from Dunaliella tertiolecta and Dunaliella salina, in order to evaluate a potentially novel industrial exploitation of these microalgae as source of phytosterols. The effect of salt concentration on sterols yields has been studied varying the quantities of NaCl into culture medium. Twelve sterols were identified by Gas-chromatographic MS/MS analysis for both algal strains. The most abundant phytosterols were (22E,24R)-methylcholesta-5,7,22-trien-3β-ol (ergosterol) and (22E,24R)-ethylcholesta-5,7,22-trien-3β-ol (7-dehydroporiferasterol). The whole sterol fraction consisted mainly of phytosterols (C28 and C29 sterols). Good yields of total sterols were achieved at lower salt concentration (1.3% and 0.89% of dry weight in D. tertiolecta and D. salina, respectively, at 0.6 M NaCl), while an increase in salt concentration resulted in a significant decrease in total sterols yield.