Isolation and Purification of Polysaccharides from Pholiota adiposa

摘要

Pholiota adiposa is an edible mushroom with excellent nutritional and medicinal properties. After culture in fermentation medium, P. adiposa mycelia were filtered, lyophilized and powdered. A crude polysaccharide (PAP) of P. adiposa was prepared from the mycelial powder with hot water, centrifuged and the resulting supernatant lyophilized. PAP was fractionated by 30%, 60% and 80% ethanol precipitation steps to yield PAP30, PAP60 and PAP80. Subsequently PAP30-1 and PAP30-2, PAP60-1 and PAP602, and PAP80-1 and PAP80-2 were isolated from PAP30, PAP60 and PAP80, respectively, by ion-exchange chromatography on a DEAE-Sepharose column. Polysaccharide content increased from 43. 8% in PAP to 50. 54%-73. 19% in PAP30-1 ~ PAP80-2. The protein content was 4. 92% at minimum in these polysaccharide products. In order to identify the chemical composition, the six polysaccharides (PAP30-1, PAP302, PAP60-1, PAP60-2, PAP80-1 and PAP80-2) were further purified by gel-filtration on Sephacrvl S-100 -500. Finally, three water-soluble polysaccharides (PAP30-2a, PAP60-2b and PAP80-2a) were obtained. HPLC analysis revealed that PAP30-2a, PAP60-2b and PAP802a exhibited a molecular weight of 6. 6×105Da, 8.4× 103Da and 3. 5×103Da, respectively.