Carbohydrate stability during ageing in Penicillium expansum cell wall.

Cell walls were obtained from Penicillium expansum mycelia of different ages. The yield of walls increased up to the 13th day of incubation and then remained almost constante. Cell walls from 13 day-old mycelia consisted of neutral sugars (65%), chitin (10%) and protein (10%). The neutral sugars released by hydrolysis of the cell wall, identified and quantified by gas-liquid chromatography were mannose (3-4%), galactose (3-4%), glucose (37%) and trace amounts of arabinose and xylose. The contents of chitin remained constant during ageing. Alkali treatment at 20 degrees C of the cell wall released and alpha-glucan amounting to about 30% leaving an insoluble residue formed by chitin and a beta-glucan containing mannose and galactose.