发酵虫草菌丝体多糖提取条件优化及其结构分析

采用响应面法优化蝙蝠蛾拟青霉菌丝体多糖的提取工艺,并对提取所得多糖的结构进行初步分析。结果表明:发酵虫草菌丝体多糖提取最佳工艺条件为提取温度98.0℃、提取时间4.5 h、液固比25∶1(mL/g),该条件下多糖得率为9.69%。菌丝体多糖主要由中性糖(84.7%)和糖醛酸(9.5%)组成。采用高效体积排阻色谱、红外光谱扫描和离子色谱对多糖结构进行光谱分析和单糖组成分析,结果表明该多糖主要为分子质量61.6 kD的单一色谱峰且可能呈吡喃环结构。另外,菌丝体多糖由阿拉伯糖、半乳糖、葡萄糖、木糖、甘露糖和半乳糖醛酸组成,其物质的量比为2.5∶31∶36∶1∶15∶4。研究成果可为日后发酵虫草菌丝体多糖精细结构与活性研究以及产品开发提供一定理论依据。

Optimization of Extraction and Structural Analysis of Polysaccharide from Paecilomyces hepiali Chen & Dai

Response surface methodology was applied to optimize polysaccharide extraction from Paecilomyces hepiali Chen & Dai. The extracted polysaccharide was structurally elucidated. The optimal extraction conditions were found to be 4.5 h extraction with hot water at 98.0 ℃ at water/material ratio of 25:1 (mL/g). Under these conditions, the maximum polysaccharide yield of 9.69% was obtained and the polysaccharide mainly composed of neutral polysaccharide (84.7%) and uronic acid (9.5%). High performance size exclusion chromatography (HPESC), high performance anion exchange chromatography and FT-IR spectroscopy were used to analyze the structural characteristics of the polysaccharide. Results showed that the molecular weight of the polysaccharide was 61.6 kD, displaying a single chromatographic peak, and its structure contained a pyran ring. In addition, the polysaccharide was composed of arabinose, galactose, glucose, xylose, mannose and galacturonic acid, with a molar ratio of 2.5:31:36:1:15:4. The findings may be useful for future studies on the structure-activity relationship of polysaccharides from Paecilomyces hepiali Chen & Dai and for the development of new polysaccharide-based products.