杏鲍菇胞外多糖液体发酵条件优化摘要 杏鲍菇是一种品质优良的名贵珍稀食用菌，有很高的营养和食用价值，其营养成分丰富，多糖含量在食用菌中位于前列。相关研究已经证明杏鲍菇多糖具有降血脂等生物功能，因此通过液体发酵获得较高的杏鲍菇胞外多糖产量具有实际意义。本研究以杏鲍菇菌丝体为实验对象，通过五个单因子实验确定杏鲍菇菌丝体发酵获得胞外多糖产量最高的培养基组分。实验结果显示最佳碳源、氮源、无机离子、pH 值和培养时间，依次分别为半乳糖、蛋白胨、磷酸二氢钾、6.0 和 9 天。在单因子实验的基础上，本文通过四因素三水平的正交实验得到杏鲍菇胞外多糖产率最高的培养基配方应为半乳糖 30 g/L，蛋白胨 5 g/L，磷酸二氢钾 3 g/L 且初始 pH 调节至 6.0，按照上述条件可得到的杏鲍菇胞外多糖得率为 5.920.84 g/L。关键词 杏鲍菇；胞外多糖；培养基优化Abstract Pleurotus eryngii is a kind of rare and precious fungus which has high nutritional and edible value. Further more, it is rich in polysaccharide content, which has been proved recently to have lipid-lowering power in blood. Therefore, the study of fluid medium optimization of P. eryngii for the improvement of the production of extracellular polysaccharide is full of practical significance. In this study, we treat mycelium as experimental subject, and carry out five single factor experiments to find out the best medium components, which are galactose as the best carbon source, peptone as the best nitrogen source, potassium dihydrogen phosphate as the best inorganic ions, 6.0 as the most suitable pH value and 9 days as the incubation time. Based on the single factor experiments, we proceed to an orthogonal experimental design which has four factors and three levels of each factor, and through this experiment we find out the optimal medium for the largest production of P. eryngii extracellular polysaccharide, which is galactose 30g/L, peptone 5g/L, potassium dihydrogen phosphate 3g/L and the initial pH value should be adjusted to 6.0. Under such conditions, the ratio of production of P. eryngii extracellular polysaccharide is 5.920.84g per liter of fermentation liquor.Keywords Pleurotus eryngii； extracellular polysaccharides；fluid medium optimization目录1 引言 .12 材料与方法 .32.1 主要材料与试剂 .32.1.1 生物材料 .32.1.2 试剂 .32.1.3 培养基 .32.2 主要设备 .32.3 试验方法 .32.3.1 菌种活化 .32.3.2 碳源单因子实验 .42.3.3 氮源单因子实验 .42.3.4 无机离子单因子实验 .42.3.5 pH 值单因子实验 .42.3.6 培养时间单因子实验 .42.3.7 液体发酵培养条件正交试验 .42.3.8 杏鲍菇菌丝体生物量测定 .42.3.9 杏鲍菇胞外多糖的提取及定量 .53 结果与讨论 .63.1 单因子实验 .63.1.1 碳源单因子实验 .63.1.2 氮源单因子实验 .73.1.3 无机离子单因子实验 .93.1.4 pH 值单因子实验 .103.1.5 培养时间单因子实验 .113.2 正交试验 .134 结论 .14致谢 .15附录 .16毕业论文相关外文文献翻译 .16参考文献 .