树干毕赤酵母发酵木糖制备乙醇补料工艺研究

XYLOSE FERMENTATION TO PREPARE ETHANOL USING PICHIA STIPITIS BY FED-BATCH METHOD

以树干毕赤酵母m4为发酵菌株,在5 L发酵罐条件下进行补料分批发酵木糖产乙醇工艺研究,以期提高发酵水平和乙醇浓度.结果表明,补料发酵时木糖初始浓度108 g/L,总浓度150g/L,发酵周期84 h;在发酵36 h时一次性补糖,酵母生长旺盛,产乙醇量最高为53.4 g/L,而补加木糖与全料培养基相比,最终乙醇浓度变化不大;在36 h前后分两次补料时,木糖转化乙醇的速率较大,乙醇产量最高为54.9 g/L.与150 g/L、108 g/L分批发酵相比,乙醇质量浓度分别提高了11.1%、19.3%.结果表明采用补料工艺可以进一步提高乙醇的产量.

We studied the xylose fed-batch fermentation process in a 5-L bioreactor using Pichia stipitis m4 to prepare ethanol,aiming to improve the fermentation level and the ethanol concentration. Results showed that the initial xylose mass concentration was 108 g/L,the total concentration was 150 g/L,and the fermentation time was84 hours during fed fermentation. When feeding xylose in one time at 36 th hour of fermentation,yeast grew strongly,the ethanol yield reached the highest value（53.4 g/L）,and the final ethanol concentration changed little because the amount of the fed xylose was small in relative to the amount of the total culture medium. When feeding xylose twice before and after 36 th hour of fermentation,the xylose transformation rate increased,the highest ethanol yield was 54.9 g/L;and the ethanol concentration was improved by 11.1% and 19.3% in comparison with 150 g/L and 180 g/L batch fermentation. The results indicate that fed-batch fermentation can further improve the ethanol yield.