POLISACCARIDI ESTRATTI DA ALGHE MARINE INVASIVE COME BIOSORBENTI DI METALLI PESANTI PER UNA STRATEGIA DI BIOREMEDIATION

Abstract

Heavy metals pollution is one of major concerns for environmental and human health. Invasive macroalgae produce large amounts of biomass often treated as waste, that could be transformed into an economic and eco-friendly resource. In this contest, we evaluated the biosorbent ability of sulphate polysaccharides (100 μg/ml) extracted from Agardhiella subulata (κ-carrageenan), Sargassum muticum (alginate) and Ulva ohnoi (ulvan) to remove arsenite (As^III), mercury (Hg^II) and vanadium (V^V) (100 ppm) from aquatic solutions. All extracts negligibly adsorbed arsenite, κ-carrageenan showed the highest adsorption level of V^V (52.5%), whereas alginate and ulvan adsorbed moderately Hg^II (about 30%). As resulted by spectroscopic analysis, the biosorption mechanisms were attributed to electrostatic attractions between functional groups of alginate or ulvan and Hg^II, and between alginate or κ-carrageenan and V^V. For their ability to adsorb both Hg^II and V^V, κ-carrageenan from Agardhiella subulata and alginate from Sargassum muticum could be proposed to develop bioremediation strategies alternative to physical or chemical techniques actually used for the heavy metals removal.