香菇是世界第二大栽培食用菌，其在加工过程中会产生大量香菇柄废弃物造成资源浪费和环境污染。该文以香菇柄为原料，通过水提分级醇沉纯化得到三种多糖LESP-20、LESP-50、LESP-80，利用化学法、高效凝胶渗透色谱、气相色谱、红外光谱对其组成及结构特性进行分析。结果表明，LESPs-50的糖含量最高，为84.31%，其相对分子质量为477.41 ku；此外，LESPs-20、LESPs-50和LESPs-80均含有Man、Glc和Gal，但单糖摩尔比存在差异；三种多糖均是含有β型糖苷键的中性杂多糖，且葡萄糖占主要成分。对香菇柄多糖（Lentinus edodes Stem Polysaccharides）LESPs进行硫酸化修饰，深入对比原始样品与硫酸化修饰后免疫调节活性的变化。结果表明，硫酸化修饰后多糖的免疫调节活性更加优越，能显著提高细胞RAW 264.7的细胞活力、吞噬能力、酸性磷酸酶活力、NO分泌量；并且硫酸基含量越高，其免疫调节活性越好。研究结果将对香菇柄的高值化开发利用提供理论依据。

Lentinus edodes is the second largest cultivated edible fungus in the world. During its process, of Lentinus edodes stem, a large amount of Lentinus edodes stem (LES) waste is generated, which causes resource waste and environmental pollution. In this study, LES was used as the raw material, three polysaccharides, LESPs-20, LESPs-50 and LESPs-80, were obtained from LES by water extraction then purification by step gradient alcohol precipitation, and their composition and structural characteristics were analyzed by chemical methods, high-performance gel permeation chromatography, gas chromatography and infrared spectroscopy. The results showed that LESPs-50 had the highest sugar content (84.31%) and its relative molecular weight was 477.41 ku. In addition, LESPs-20, LESPs-50 and LESPs-80 all contained Man, Glc and Gal, but their molar ratios of monosaccharides differed. All the three polysaccharides were neutral heteropolysaccharides containing β-glucosidic bonds, with glucose being the main component. The LESPs were sulfated and the differences in immunomodulatory activity between the original sample and the sulfated sample were compared in depth. The results showed that the immunomodulatory activities of the sulfated polysaccharides were superior, and they could improve the cell viability, phagocytic ability, acid phosphatase activity and the amount of secreted NO of RAW 264.7 cells. The higher the content of sulfate group, the better the immunomodulatory activity. The results of this study will provide a theoretical basis for the high-value development and utilization of the Lentinus edodes stem.

国家自然科学基金项目（31801491）；西安市科技局农业技术研发项目（22NYYF032）；陕西省科协青年托举人才项目（20220216）