微生物混合碳源发酵过程普遍存在“代谢物阻遏效应”，产丁醇梭菌属微生物转化木质纤维素原料生产丁醇过程中，水解液中五碳糖与六碳糖的同步同等利用成为亟待解决的难题。单糖利用的偏好性导致其在利用水解液发酵时，出现发酵周期长、底物利用率低、废水处理成本高等一系列问题。开发能够同步利用五碳糖与六碳糖的菌株，对于木质纤维素原料生物转化至关重要。以申请者筛选得到的一株能够同步利用葡萄糖与木糖的拜氏梭菌C. beijerinckii SE-2及存在“葡萄糖效应”的丙酮丁醇梭菌C. acetobutylicum ATCC 824为研究对象，以木糖与葡萄糖分别作为五六碳糖模式物，研究产丁醇梭菌属微生物五六碳糖的转运特性及差异，阐明葡萄糖与木糖转运途径，揭示产丁醇梭菌属微生物葡萄糖与木糖转运过程关键蛋白基因的作用机制，为构建五六碳糖同步利用基因工程菌提高木质纤维素水解液发酵过程底物利用率奠定理论基础。

Carbon catabolite repression is a common phenomenon during the fermentation of mixed carbon sources. The simultaneous utilization of pentoses and hexoses in the production of butanol from lignocellulosic biomass by Clostridium species has been an important task to accomplish. Favoring certain types of monosaccharides during fermentation results in problems such as prolonged fermentation period, lowered efficiency of substrate utilization and high costs for wastewater treatment. Developing strains that can simultaneously utilize pentoses and hexoses is of paramount importance for highly efficient lignocellulose bioconversion. Investigations carried out in this project focuses on the glucose-xylose simultaneously utilizing C. beijerinckii SE-2 that the applicant previously isolated and identified, as well as C. acetobutylicum ATCC824 for which the ‘glucose repression effect’ is apparent. Using glucose and xylose as the respective model monosaccharide for hexose and pentose, the research on the properties and differences of monosaccharide transportation will be carried out for butanol-producing Clostridium species. The mechanisms of glucose and xylose transporting pathway will be further elucidated, which will reveal the mechanisms of the key proteins in this pathway in Clostridium species. These investigations will set the basis for improving the efficiency of lignocellulose hydrolysate utilization by constructing engineer strains that have the capability of pentose-hexose simultaneous utilization.