Abstract: A new lentinan extracting technology from lentinus edodes was developed with neutral proteinase,and the separation of lentinan by microfiltration was studied as well.The crude powder of lentinus edodes was treated by neutral proteinase before extraction in water.The optimized enzyme-based extraction conditions are as follows:treatment temperature 50℃,pH value of extraction media 5.0,extraction time 60 min and mass ratio of enzyme to lentinus edodes 1.5:100.Comparing with traditional extracting technology by water,the extraction yield of lentinan increases 40%,and the concentration of protein decreases 50% with the enzyme-based extracting technology.With two kinds membrane molecular weight cut-off 50 kD and 300 kD,the lentinan is separated into three parts:the small molecular weight polysaccharides without protein,the middle molecular weight polysaccharides with a tittle protein,and the large molecular weight polysaccharides with large amount of protein.The optimized separation conditions of ultrafiltration are as follows:temperature 35℃,pH value 7 and pressure 0.15MPa.

Key words: lentinan, neutral proteinase, enzyme treatment, ultrafiltration, classify