一株葡萄糖和木糖共发酵高效产乙醇重组运动发酵单胞菌的性能评价

Evaluation on glucose-xylose co-fermentation by a recombinant Zymomonas mobilis strain

摘要:

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。

Abstract:

Co-fermentation of glucose and xylose is critical for cellulosic ethanol, as xylose is the second most abundant sugar in lignocellulosic hydrolysate. In this study, a xylose-utilizing recombinant Zymomonas mobilis TSH01 was constructed by gene cloning, and ethanol fermentation of the recombinant was evaluated under batch fermentation conditions with a fermentation time of 72 h. When the medium containing 8% glucose or xylose, was tested, all glucose and 98.9% xylose were consumed, with 87.8% and 78.3% ethanol yield, respectively. Furthermore, the medium containing glucose and xylose, each at a concentration of 8%, was tested, and 98.5% and 97.4% of glucose and xylose was fermented, with an ethanol yield of 94.9%. As for the hydrolysate of corn stover containing 3.2% glucose and 3.5% xylose, all glucose and 92.3% xylose were consumed, with an ethanol yield of 91.5%. In addition, monopotassium phosphate can facilitate the consumption of xylose and enhance ethanol yield.