Chemical characterization of a water insoluble (1 → 3)-α-d-glucan from an alkaline extract of Aspergillus wentii

The chemical structure of a water insoluble α-glucan isolated from the cell wall of Aspergillus wentii was described on the basis of total acid hydrolysis, methylation analysis, and 1D and 2D NMR studies (TOCSY, DQF-COSY, NOESY and HSQC) as well as other instrumental techniques. It was established that the analyzed preparation contained a linear polymer composed almost exclusively of (1 → 3)-linked α-d-glucose, with a molecular mass of about 850 kDa. The polymer was divided into subunits separated by a short spacers of (1 → 4)-linked α-d-glucoses. Each subunit contained about 200 glucose residues.