Natural porous agar materials from macroalgae.

Porous agar materials have been prepared from marine macroalgae species using a simple microwave-assisted extraction/drying methodology, providing a new family of polysaccharide derived porous solids. The microwave-assisted extraction allows a more efficient and less time-consuming extraction of the polysaccharide compared to conventional extraction protocols based on conventional heating. DRIFT and (13)C NMR results indicated that the internal agar structure (based on d-galactose and 3,6-anhydro-l-galactose linked units) was preserved after the extraction methodology, which opens a wide range of future possibilities and applications for this new family of porous polysaccharides. The extracted agar materials, which have already applications per se due to their high purities, could be subsequently transformed into a novel family of attractive mesoporous agar materials that could be used as natural templates for the production of nanocrystals of metal oxides.

Phytosterols from Dunaliella tertiolecta and Dunaliella salina: a potentially novel industrial application.

Sterols have been extracted and analysed from Dunaliellatertiolecta 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-3beta-ol (ergosterol) and (22E,24R)-ethylcholesta-5,7,22-trien-3beta-ol (7-dehydroporiferasterol). The whole sterol fraction consisted mainly of phytosterols (C(28) and C(29) 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 0.6M NaCl), while an increase in salt concentration resulted in a significant decrease in total sterols yield.