目的探索桦褐孔菌深层发酵体系中胞外多糖积累的最佳碳、氮源和pH值。方法采用深层发酵法培养桦褐孔菌,通过添加不同的碳、氮源和改变pH值观察胞外多糖的积累。发酵液中的总糖用硫酸-蒽酮法测定,还原糖以DNS法测定,总糖减去还原糖即为胞外多糖的量。结果桦褐孔菌深层发酵体系中有利于胞外多糖合成的最佳碳源为2%的麦芽糖,氮源为0.4%的蛋白胨,最适pH值为5.5。结论最佳单因子组合对桦褐孔菌胞外多糖积累有协同效应,组合后的发酵体系中胞外多糖的量达7.8g/L。

Objective To optimize the sources of carbon and nitrogen and pH value favoring the accumulation of extracellular polysaccharides in the submerged fermentation of Inonotus obliquus.Methods The accumulation of extracellular p01ysaccharides was monitored in the submerged fermentation of I.obliquusby supplementation of various carbon and nitrogen sources and alteration of initial pH level.The total sugar was determined by sulfuric acid-anthrone method；sugar was reduced by DNS method；the accumulation of extracellular polysaccharides was calculated by subtracting the reductive sugar from the total sugar.Results The optimal surbserged fermentation favoring the accumulation of extrac ellular polysaccharides consisted of 2% maltose and 0.4% peptone as the carbon and nitrogen sources,respectively,and the pH value was 5.5.Conclusion The combination of optimal carbon and nitrogen sources and pH level indicats synergism on the accumulation of extracellular polysaccharides in the submerged fermentation of I.obliquus.The amount of extracellular polysaccharides is up to 7.8 g/L at the end of fermentation.

江苏省高校自然科学研究计划重大基础研究项目(05KJA36012);江苏省自然科学基金项目(BK2006034);徐州市科技计划重点项目(06XZA008)