休哈塔假丝酵母乙醇发酵性能的研究

木糖的高效发酵是制约纤维素燃料乙醇生产的技术瓶颈之一,高性能发酵菌种的开发是本领域研究的重点。以木糖发酵的典型菌株休哈塔假丝酵母为材料,研究氮源配比、葡萄糖和木糖初始浓度、葡萄糖添加及典型抑制物等因素对其木糖利用和乙醇发酵性能的影响规律。结果表明,硫酸铵更适宜于木糖和葡萄糖发酵产乙醇。在摇瓶振荡发酵条件下,该酵母可发酵164.0 g/L葡萄糖生成61.9 g/L乙醇,糖利用率和乙醇得率分别为99.8%和74.0%;受酵母细胞膜上转运体系的限制,对木糖的最高发酵浓度为120.0 g/L,可生成45.7 g/L乙醇,糖利用率和乙醇得率分别达到94.8%和87.0%。休哈塔假丝酵母发酵木糖的主要产物为乙醇,仅生成微量的木糖醇;添加葡萄糖可促进木糖的利用;休哈塔假丝酵母在葡萄糖发酵时的乙酸和甲酸的耐受浓度分别为8.32和2.55 g/L,木糖发酵时的乙酸和甲酸的耐受浓度分别为6.28和1.15 g/L。

Ethanol Fermentation Performance by Candida shehatae

The efficient xylose fermentation is one of bottlenecks in cellulose fuel ethanol production,the development of high-performance strain is the key in the research field.In this research Candida shehatae was taken as typical strain in xylose fermentation material to study the proportion of different nitrogen sources,the initial concentration of glucose and xylose,the effect laws of the addition of glucose and typical inhibitor and other factors on the utilization of xylose,and ethanol fermentation performance were studied in this paper.The results showed that ammonium sulfate was even more suitable for xylose and glucose to ferment and produce ethanol.Under the shaking flask fermentation conditions,the yeast could ferment 164.0 g/L of glucose to produce 61.9 g/L of ethanol with sugar utilization rate and ethanol gaining rate at 99.8% and 74.0% respectively;restricted by transferring system of the yeast membrane,the highest fermentation concentration of xylose was 120.0 g/L that could produce 45.7 g/L of ethanol with sugar utilization rate and ethanol gaining rate at 94.8% and 87.0 g/L respectively.During xylose fermentation by C.shehatae,the main product was ethanol and trace of xylitol;And by adding glucose could promote xylose utilization;The tolerance concentration of acetic acid and formic acid during the glucose fermentation were respectively 8.32 g/L and 2.55 g/L and respectively 8.32 g/L and 1.15 g/L during the xylose fermentation.