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Chemical characterization of alkali-soluble polysaccharides isolated from a Boletus edulis (Bull.) fruiting body and their potential for heavy metal biosorption

Choma, Adam, Nowak, Katarzyna, Komaniecka, Iwona, Waśko, Adam, Pleszczyńska, Małgorzata, Siwulski, Marek, Wiater, Adrian
Food chemistry 2018 v.266 pp. 329-334
Boletus edulis, Fourier transform infrared spectroscopy, biosorption, cadmium, cell walls, chemical analysis, chemical structure, copper, fruiting bodies, heavy metals, ingredients, lead, metal ions, molecular weight, mushrooms, nuclear magnetic resonance spectroscopy, polymers, polysaccharides, zinc
Wild mushrooms are gathered and consumed in many regions of the world. Edible mushrooms are a good source of valuable nutritious ingredients but they also are able to accumulate heavy metals from the environment. Participation of polysaccharide components of mushroom cell walls in biosorption is poorly understood, therefore, our investigations focussed on an alkali-soluble polysaccharide derived from the cell wall of Boletus edulis. Its chemical structure is described based on chemical analysis, GPC, NMR and FT-IR and other instrumental techniques. The polysaccharide contained mainly C-3 substituted α-d-glucose and α-d-mannose. The ratio between these components was 10:4. We postulate the polymer is a (1 → 3)-linked α-d-glucan decorated by α-(1 → 3)-d-mannose chains. The molecular mass of the polysaccharide was estimated at about 850 kDa. Biosorption of heavy metal ions (Cd, Cu, Zn and Pb) by the tested polymer was measured using AAS techniques. The polysaccharide has a high ability to accumulate lead and cadmium.