高浓度糖发酵制备乙醇

以树干毕赤酵母为发酵菌株，混合糖（木糖、葡萄糖）为发酵底物，通过培养基和培养条件的改变来确定树干毕赤酵母高糖浓度发酵时所需的条件。研究结果表明：在24h发酵周期内初始木糖质量浓度为63．0g／L较适宜；在36h发酵周期内初始木糖质量浓度为72．0g/L较适宜。24h发酵周期内，在36．0g／L木糖中添加的葡萄糖质量浓度以54．0g/L为最佳，发酵结束乙醇质量浓度达32．9g／L；36h发酵周期内，添加的葡萄糖质量浓度以72．0g／L为最佳，发酵结束乙醇质量浓度为36．9g／L。以（NH4）2SO4为N源时较适合戊糖发酵制备乙醇，（NH2）2SO4的最佳质量浓度为1．1g／L。发酵前8h摇床转速为90r／min，后16h为150r／min，乙醇质量浓度较高，可达17．5g/L。

High concentration fermentation of pentose to ethanol

Fermentation of glucose-xylose mixture to ethanol with Pichia stipitis was investigated. High concentration fermentation conditions were optimized by changing culture medium and cultivation conditions. The results showed that the initial xylose concentration of 63.0 g/L was appropriate in 24 h and initial xylose concentration of 72. 0 g/L was suitable in 36 h. It was optimal by adding 54 g/L glucose in 24 h. The concentration of ethanol was 32. 9 g/L. Further it was optimal by adding 72. 0 g/L glucose in 36 h. The concentration of ethanol was 36. 9 g/L. It was fit for（NH4）2SO4 to fermentation of ethanol with xylose. The concentration of （NH4）2SO4 was 1.1 g/L. Rotate speed of swing bed remained at 90 r/min in the first 8 h, then at 150 r/min after 16 h. The concentration of ethanol reached 17. 5 g/L.