Polysaccharide Fractionation By Ultrafiltration-a Novel Method For Isolation And Purification Of Lentinan From Lentinus Edodes

A new process was proposed to improve the traditional process for isolation and purification of lentinan, an efficient antitumor agent. Lentinan, one of mushroom polysaccharides could be extracted from lentinus edodes into aqueous solution under optimal conditions (solid/deionized water = 1:100, decocting at 90℃for 6 h). Then some methods were tried to remove protein in an efficient way, such as enzymatic method, which could eliminate protein greatly and keep the content of polysaccharide invariable as well, the ratio of protein removed was up to 88.1%. Isolation and purification of lentinan by ultrafiltration was studied, diafiltration was used to separate proteins and other impurities from lentinan aqueous solution. Finally the product could be obtained by cryodring. A sententious and rapid analytic method to measure the content of polysaccharide in final product named Elisa was also investigated. Compare with the IR spectrum of the product with the standard one, we could come to the conclusion that the product through this new process is lentinan. The purity of crude lentinan is 72.8%, and the recovery yield is 0.67%. The result indicates the method of purification by ultrafiltration can improve the traditional abstraction procedure of polysaccarides greatly, and produce lentinan cost-effectively.