Mannoglucogalactans from the cell walls of Penicillium erythromellis: Isolation and partial characterisation

Abstract

Cell-wall material from Penicillium erythromellis was extracted with m sodium hydroxie at 20°. After neutralisation and dialysis of the alkali-soluble material, two polysaccharidic fractions were isolated, namely, a β-glucan (glucose, 49%) containing galactose (6.9%), xylose (3.7%), mannose (1.9%), and protein (9%), and a glucogalactan (glucose, 15%) with galactofuranosyl residues (39%), containing mannose (5.3%) and protein (18%). Borate anion-exchange chromatography of the glucogalactan gave five polysaccharides, the relative amounts of which, in order of elution, were 1.5:1.0:2.4:7.1:2.1. When the three polysaccharides with the highest carbohydrate content were subjected to methylation analysis, one was shown to be a (1→4)-α- d-glucan with branch points at positions 6 (12.2%), and glucopyranose (5.8%) and galactofuranose (3.4%) as terminal residues, and the others to be β-glucogalactans with diffrent proportions of galactofuranose and glucopyranose residues. The galactofuranosyl residues were (1→2)-linked with branch points at positions 6, and galactofuranose as terminal residues. The glucopyranosyl residues were mainly (1→4)-linked with glucopyranose as terminal residues.