Abstract: Orthogonal design was used to explore the optimum organic nitrogen sources for lentinus edodes fermentation and the best ratio of the three nitrogen sources in the medium is that bean powder is 1, yeast extract paste 1.5, tryptone 0.2. The results also indicate that bean powder is the best nitrogen source for lentinus edodes fermentation. Subsequently, lentinus edodes was cultured in the optimum medium for 130 h and the concentration of lentinen in the fermentation medium could reach the climax of 25.1 mg/mL. lentinen was crudely extracted from the liquid medium by alcohol precipitation, then deproteinized by the Sevag method from the polysacchrides and the deproteinized lentinen was purified by gel filtration with Sephadex G-75 to obtain two components of lentinen.

Key words: orthogonal design, lentinus edodes, fermentation, lentinen