地生枝顶孢胞外多糖的理化性质和结构初步分析

报道分离自地生枝顶孢Acremonium terricola RCEF0260菌株发酵滤液中的胞外多糖EPS-Ia的理化性质和一级结构。EPS-Ia分子量为416kD,至少含有D-甘露糖、D-葡萄糖、D-半乳糖、D-阿拉伯糖、D-木糖,各单糖摩尔比为4.46: 0.24: 2.38: 0.90: 0.19。糖醛酸含量为27.4%。硫酸基含量0.92%、蛋白质含量2.23%。氨基酸组成分析显示:EPS-Ia中含有17种常见氨基酸。EPS-Ia为型吡喃糖,含有1→3糖苷键,1→6糖苷键及1→2糖苷键,其中的糖肽键是N-糖苷键。

PHYSICAL AND CHEMICAL PROPERTIES AND STRUCTURE OF EXOPOLYSACCHARIDE OF ACREMONIUM TERRICOLA

In the paper, physical and chemical properties and primary structure of exopolysaccharide EPS-Ia from fermentation filtrate of Acremonium terricola strain RCEF0260 were studied. The average molecular weight of EPS-Ia determined by gel chromatography was 416kD. EPS-Ia was composed of D-Man, D-Glu, D-Gal, D-Ara and D-Xyl in molar ratio of 4.46:0.24:2.38:0.90:0.19 determined by gas chromatography. EPS-Ia contains glucuronic acid, sulphate and protein, which are 27.4%, 0.92% and 2.23% respectively. The infrared spectrum indicated that glucosidal linkage in EPS-Ia was pyranose. The assay of dilute alkali suggested that the polysaccharide chain is linked to peptide chain through N-glucosidal bond. Petriodate oxidation and Smith degradation studies showed that EPS-Ia was composed of 1-3, 1-6 and 1-2 linked glucosyl bond.