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木糖是木质纤维素原料水解液中的第二大组分,木糖和葡萄糖的充分利用是有经济性地生产纤维素乙醇的关键。通过基因克隆手段构建了一株可以高效利用木糖产乙醇的重组运动发酵单胞菌Zymomonas mobilis TSH01,并进行了利用单糖溶液、混合糖溶液及玉米秸秆水解液发酵产乙醇效率的研究。结果表明,利用单一葡萄糖或单一木糖溶液发酵时,当糖浓度为8%、发酵72 h后,糖利用率分别为100%和98.9%,乙醇代谢收率分别为87.8%和78.3%;利用8%葡萄糖和8%木糖的混合溶液发酵时,72 h后,葡萄糖和木糖的利用率分别为98.5%和97.4%,乙醇代谢收率为94.9%。利用含3.2%葡萄糖和3.5%木糖的玉米秸秆水解液发酵72 h后,葡萄糖和木糖的利用率分别为100%和92.3%,乙醇代谢收率为91.5%。此外,磷酸二氢钾对发酵过程中木糖利用率以及乙醇收率的提高有明显促进作用。
Xylose is the second largest component of the lignocellulosic feedstock hydrolyzate. The full utilization of xylose and glucose is the key to producing cellulosic ethanol economically. A recombinant strain of Zymomonas mobilis TSH01, which can efficiently utilize xylose ethanol, was constructed by gene cloning. The efficiency of ethanol fermentation by using monosaccharide solution, mixed sugar solution and corn stalk hydrolyzate was studied. The results showed that when using single glucose or single xylose fermentation, the sugar utilization rate was 100% and 98.9% respectively when the sugar concentration was 8% and the fermentation time was 72 h, the ethanol yield was 87.8% and 78.3% respectively. After 72 h of fermentation, the utilization rates of glucose and xylose were 98.5% and 97.4%, respectively. The yield of ethanol metabolism was 94.9% after 8% and 8% xylose fermentation. After 72 h fermentation with corn stalk hydrolyzate containing 3.2% glucose and 3.5% xylose, the utilization rates of glucose and xylose were 100% and 92.3%, respectively, and the ethanol yield was 91.5%. In addition, potassium dihydrogen phosphate on the fermentation process of xylose utilization and ethanol yield improved significantly.