木质纤维素全糖（葡萄糖、木糖、阿拉伯糖、甘露糖和半乳糖）的利用是提高生物化学品发酵指标的关键。然而，发酵微生物中碳分解代谢物阻遏效应（CCR）的存在以及脱毒过程中非葡萄糖单糖的大量损失，阻碍了木质纤维素中非葡萄糖单糖的利用。本项目提出在L-乳酸生产菌株乳酸片球菌中整合全糖共发酵路径同时强化其抑制物抗逆性，以突破非葡萄糖单糖利用瓶颈。包括：通过异源阿拉伯糖代谢路径的整合，构建具备全糖代谢路径的工程菌；多种代谢工程策略弱化菌株的CCR，获得全糖共发酵菌株的同时探究出适用于乳酸片球菌的CCR弱化方案；结合适应性进化及代谢工程提高醛类抑制物（糠醛、丁香醛、苯醌等）抗逆性，实现对醛类抑制物的自解毒，从而缩短生物脱毒周期同时保留非葡萄糖单糖；优化生物脱毒周期，获得非葡萄糖单糖有效保留的玉米秸秆进行全糖共发酵产L-乳酸。本项目有望实现木质纤维素全糖组分的高效利用，并为全糖共发酵菌株的构建奠定方法学基础。

The efficient utilization of lignocellulose derived all-sugars (glucose, xylose, arabinose, mannose and galactose) plays a key role in improving the fermentation performance of biochemicals. However, the existence of Carbon Catabolite Repression (CCR) in the fermenting microorganisms and the massive losses of non-glucose sugars during detoxification process, together result in the poor utilization of non-glucose sugars in lignocellulose. In this project, we propose to simultaneously construct the all-sugars co-assimilating pathways and strengthen inhibitors tolerance into the L-lactic acid producing strain Pediococcus acidilactici, to overcome the above bottlenecks of non-glucose sugars utilization. The all-sugars assimilating pathways will be constructed into P. acidilactici by genome integration of the heterologous arabinose assimilating pathways. Multiple metabolic engineering strategies will be applied to weaken the CCR of the engineered strain, to obtain the all-sugars co-fermenting strain and discover the optimal strategy for weakening CCR in P. acidilactici. The aldehyde inhibitors (furfural, syringaldehyde, p-benzoquinone, et al) tolerance will be strengthened based on the combination of adaptive evolution and metabolic engineering for detoxifying the aldehyde inhibitors by the strain itself, leading to the shortened biodetoxification period and minimum losses of non-glucose sugars. The optimal biodetoxification period will be explored to obtain the corn stover feedstock containing non-glucose sugars for producing L-lactic acid by all-sugars co-fermentation. This study will realize the efficient co-fermentation of all-sugars in lignocellulose and lay a methodological basis for the construction of lignocellulose derived all-sugar co-fermenting microorganisms.