液态发酵灵芝菌丝体多糖提取工艺的优化及其理化特征的分析

Optimization of extraction and physicochemical characteristics analysis of polysaccharides from liquid fermentation mycelia of Ganoderma lingzhi

本研究以发酵专用高产多糖灵芝菌株GZ36为材料,通过调控发酵时间以实现目标多糖的定向富集,对获得的发酵菌丝体胞内多糖的提取工艺进行优化,并对制备的多糖组分的理化特征及免疫活性进行了研究。研究表明,发酵时间为60 h时菌丝体胞内多糖的含量最高,未经干燥处理的菌丝体的多糖提取得率相对于烘干处理的菌丝体提高了60.42%,相对于冷冻干燥菌丝体提高了59.16%。未干燥处理灵芝菌丝体的多糖最佳提取工艺为:提取温度90℃、料液比1:3(g/mL)、提取时间2 h,提取次数2次,在此条件下多糖的提取得率可达6.10%。利用分级醇沉从菌丝体的提取液中得到了4个组分GLP-10E、GLP-20E、GLP-50E和GLP-75E,其中GLP-10E、GLP-20E的重均分子量分别为6.161×10^(6) g/mol、4.112×10^(6) g/mol,多糖含量分别为84.59%、92.30%,这2个组分中葡萄糖占比均达到了98%;GLP-50E主要由葡萄糖、甘露糖、鼠李糖以及少量的木糖组成;GLP-75E组分中含有大量的氨基葡萄糖。4个多糖组分均具有诱导巨噬细胞释放NO的活性。本研究可为灵芝液态发酵菌丝体多糖的开发利用提供参考。

Ganoderma polysaccharide is one of the important bioactive ingredients in Ganoderma lingzhi.It has unique advantages in obtaining Ganoderma mycelium polysaccharides by liquid fermentation.In this study,Ganoderma lingzhi strain GZ36 was selected for liquid fermentation.The enrichment of target polysaccharide components was carried out by regulating the fermentation time,and the extraction process of intracellular polysaccharides of fermented mycelium was optimized.The physicochemical characteristics and immunomodulatory activities of polysaccharides obtained were analysed.The results showed that intracellular polysaccharide content of the mycelium was the highest in 60 hours of fermentation.The extraction rate of polysaccharides from fresh mycelia was 60.42% higher than that from dried mycelia and 59.16% higher than that from freeze-dried mycelia.The optimal extraction process for Ganoderma mycelial polysaccharides was:extraction temperature of 90℃,liquid-to-solid ratio of 1:3(g/mL),extraction time of 2 hours,and two times of extraction cycles.Under these conditions,the acquisition rate of polysaccharides could reach 6.10%.Four polysaccharide components,GLP-10E,GLP-20E,GLP-50E and GLP-75E were obtained from graded alcohol precipitation,of which GLP-10E and GLP-20E had relatively large average molecular weights of 6.161×10^(6) g/mol and 4.112×10^(6) g/mol respectively,and the polysaccharide content in these two components reached 84.59% and 92.30% respectively,and the proportion of glucose reached 98%.It is speculated that these two components are glucan.GLP-50E is mainly composed of glucose,mannose,rhamnose,and a small amount of xylose.GLP-75E component contains a large amount of glucosamine.All four polysaccharide components have the activities of inducing macrophages to release NO.The study provides a reference for the better development and utilization of polysaccharides from liquid fermentation of Ganoderma mycelia.