Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin Universitygrid.33763.32, Tianjin, China.
Frontier Science Center for Synthetic Biology (Ministry of Education), School of Chemical Engineering and Technology, Tianjin Universitygrid.33763.32, Tianjin, China.
Appl Environ Microbiol. 2022 Dec 13;88(23):e0151822. doi: 10.1128/aem.01518-22. Epub 2022 Nov 16.
Xylose, the major component of lignocellulosic biomass, cannot be naturally or efficiently utilized by most microorganisms. Xylose (co)utilization is considered a cornerstone of efficient lignocellulose-based biomanufacturing. We evolved a rapidly xylose-utilizing strain, Cev2-18-5, which showed the highest reported specific growth rate (0.357 h) on xylose among plasmid-free Corynebacterium glutamicum strains. A genetically clear chassis strain, CGS15, was correspondingly reconstructed with an efficient glucose-xylose coutilization performance based on comparative genomic analysis and mutation reconstruction. With the introduction of a succinate-producing plasmid, the resulting strain, CGS15-SA1, can efficiently produce 97.1 g/L of succinate with an average productivity of 8.09 g/L/h by simultaneously utilizing glucose and xylose from corn stalk hydrolysate. We further revealed a novel xylose regulatory mechanism mediated by the endogenous transcription factor IpsA with global regulatory effects on C. glutamicum. A synergistic effect on carbon metabolism and energy supply, motivated by three genomic mutations (-, -, and ), was found to endow C. glutamicum with the efficient xylose utilization and rapid growth phenotype. Overall, this work not only provides promising C. glutamicum chassis strains for a lignocellulosic biorefinery but also enriches the understanding of the xylose regulatory mechanism. A novel xylose regulatory mechanism mediated by the transcription factor IpsA was revealed. A synergistic effect on carbon metabolism and energy supply was found to endow C. glutamicum with the efficient xylose utilization and rapid growth phenotype. The new xylose regulatory mechanism enriches the understanding of nonnatural substrate metabolism and encourages exploration new engineering targets for rapid xylose utilization. This work also provides a paradigm to understand and engineer the metabolism of nonnatural renewable substrates for sustainable biomanufacturing.
木糖是木质纤维素生物质的主要成分,大多数微生物无法自然或高效地利用它。木糖(共)利用被认为是高效木质纤维素生物制造的基石。我们进化出了一种快速利用木糖的菌株 Cev2-18-5,它在无质粒谷氨酸棒杆菌菌株中显示出最高的报道比生长速率(0.357 h)。基于比较基因组分析和突变重建,相应地构建了一种遗传清晰的底盘菌株 CGS15,具有高效的葡萄糖-木糖共利用性能。通过引入琥珀酸产生质粒,所得菌株 CGS15-SA1 可以通过同时利用玉米秸秆水解物中的葡萄糖和木糖,高效生产 97.1 g/L 的琥珀酸,平均产率为 8.09 g/L/h。我们进一步揭示了一种由内源性转录因子 IpsA 介导的新型木糖调控机制,对谷氨酸棒杆菌具有全局调控作用。通过三个基因组突变(-、-和)发现,一种对碳代谢和能量供应的协同作用,使谷氨酸棒杆菌具有高效利用木糖和快速生长的表型。总的来说,这项工作不仅为木质纤维素生物炼制提供了有前途的谷氨酸棒杆菌底盘菌株,而且丰富了对木糖调控机制的理解。揭示了一种由转录因子 IpsA 介导的新型木糖调控机制。通过三个基因组突变(-、-和)发现,一种对碳代谢和能量供应的协同作用,使谷氨酸棒杆菌具有高效利用木糖和快速生长的表型。新的木糖调控机制丰富了对非天然底物代谢的理解,并鼓励探索快速利用木糖的新工程目标。这项工作还为理解和工程化非天然可再生底物的代谢提供了一个范例,以实现可持续的生物制造。