Biochemical characterization of <i>Macrocystis pyrifera</i> and <i>Undaria pinnatifida</i> (Phaeophyceae) in relation to their potentiality as biosorbents

Abstract

Undaria pinnatifida and Macrocystis pyrifera from Patagonia were characterized in terms of the alginate, protein, total carbohydrate and organic matter content, cation exchange capacity and acid-base properties to assess the suitability of both species as potential biosorbents of metals. Environmental scanning electron microscopy equipped with an energy dispersive X-ray microanalysis system, Fourier transform infrared spectroscopy (FT-IR) and Brunauer, Emmett and Teller surface area analysis were also applied for characterization. The results showed that U. pinnatifida had a higher percentage of organic matter, alginate and protein and a larger specific surface area than M. pyrifera, although the latter exhibited a higher ionic exchange capacity. The groups with a weak acid behaviour represented 84% and 97% of the total acid groups in M. pyrifera and U. pinnatifida, respectively. FT-IR analysis confirmed the presence of different chemical groups such as sulphonate in both biomaterial M. pyrifera and U. pinnatifida. Besides, Zn(II) adsorption capacity was different among different parts of the thallus of each species. The difference founded in the physicochemical properties of both algae could affect their biosorption capacities.