Simple and effective purification approach to dissociate mixed water-insoluble α- and β-D-glucans and its application on the medicinal mushroom Fomitopsis betulina.

Differences in anomericity and in the branching degree of glucans lead to characteristic intermolecular association that influences their solubility in water or other solvents. A simple purification approach, based on the glucan solubility in aq. 0.1 M NaOH solution, was applied for the separation of mixed water-insoluble α-D-glucans from β-D-glucans extracted from fruiting bodies of Fomitopsis betulina, which is an underexploited medicinal mushroom. The results indicated that the β-D-glucan is constituted by (1→3)-linked β-D-Glcp units substituted at O-6 by non-reducing β-D-Glcp and (1→6)-linked β-D-Glcp units, while the α-D-glucan has a linear (1→3)-linked glucan structure. Thus, the 0.1 M NaOH treatment proved to be a simple, efficient and low-cost purification method for separation of water-insoluble glucans with different anomeric configurations and degree of branching that were interacting by intermolecular forces.