里氏木霉产胞外多糖发酵条件的优选研究

目的：建立简便有效的里氏木霉胞外多糖提取发酵工艺，为木霉胞外多糖的进一步开发利用奠定基础。方法以粗胞外多糖产量为指标，采用单因素试验优化发酵培养基配方，利用正交试验对摇瓶培养过程中的发酵液初始 pH、孢子接种量、发酵温度及发酵时间进行优选。结果里氏木霉发酵最佳控制参数为：培养基配方为蔗糖50 g/L、酵母粉20 g/L、K2HPO4·3H2O 8 g/L、MgSO40.5 g/L；发酵条件为发酵液初始 pH5.0、孢子接种量10%、发酵温度28℃、发酵时间190 h。优选发酵条件下里氏木霉粗胞外多糖产量达到21.6 g/L（RSD=2.54%， n=3）。结论优化的里氏木霉胞外多糖发酵提取工艺是一种简便、合理、可行和产量较高的提取工艺。

Optimization of fermentation conditions for exopolysaccharides from Trichoderma reesei

Objective To optimize fermentation conditions for exopolysaccharides from Trichoderma reesei, establish a simple and effective fermentation process and lay a foundation of further study on its biological activities. Methods Taking exopolysaccharides yield as an index,culture medium formula was optimized by single-factor experiment,and then fermentation conditions (initial pH value of medium,spore inoculation amount,fermentation temperature and fermentation time)were optimized by orthogonal test. Results The optimized fermentative conditions are as follows:culture medium formula:sucrose 50 g/L,yeast powder 20 g/L,K2HPO4·3H2O 8 g/L,MgSO4 0.5 g/L;fermentation conditions:initial pH value of medium 5.0,spore inoculation amount 10%,fermentation temperature 28 ℃and fermentation time 190 h.Under the optimized fermentation conditions,the extracellular polysaccharides of Trichoderma reesei reached 21.6 g/L (RSD=2.54% n=3).Conclusion The optimum fermentation process is simple, reasonable and feasible.