Wang Ming, Luan Tao, Zhao Jianzhi, Li Hongxing, Bao Xiaoming
State Key Laboratory of Biobased Material and Green Papermaking, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, China.
State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Qingdao 266237, Shandong, China.
Sheng Wu Gong Cheng Xue Bao. 2021 Mar 25;37(3):1042-1057. doi: 10.13345/j.cjb.200708.
Effective utilization of xylose is a basis for economic production of biofuels or chemicals from lignocellulose biomass. Over the past 30 years, through metabolic engineering, evolutionary engineering and other strategies, the metabolic capacity of xylose of the traditional ethanol-producing microorganism Saccharomyces cerevisiae has been significantly improved. In recent years, the reported results showed that the transcriptome and metabolome profiles between xylose and glucose metabolism existed significant difference in recombinant yeast strains. Compared with glucose, the overall process of xylose metabolism exhibits Crabtree-negative characteristics, including the limited glycolytic pathway activity, which reduces the metabolic flux of pyruvate to ethanol, and the enhanced cytosolic acetyl-CoA synthesis and respiratory energy metabolism. These traits are helpful to achieve efficient synthesis of downstream products using pyruvate or acetyl-CoA as precursors. This review provides a detailed overview on the modification and optimization of xylose metabolic pathways in S. cerevisiae, the characteristics of xylose metabolism, and the construction of cell factories for production of chemicals using xylose as a carbon source. Meanwhile, the existed difficulties and challenges, and future studies on biosynthesis of bulk chemicals using xylose as an important carbon source are proposed.
有效利用木糖是从木质纤维素生物质经济生产生物燃料或化学品的基础。在过去30年里，通过代谢工程、进化工程等策略，传统产乙醇微生物酿酒酵母的木糖代谢能力得到了显著提高。近年来，报道结果表明，重组酵母菌株中木糖代谢和葡萄糖代谢之间的转录组和代谢组谱存在显著差异。与葡萄糖相比，木糖代谢的整个过程表现出克奈特阴性特征，包括糖酵解途径活性受限，这降低了丙酮酸向乙醇的代谢通量，以及胞质乙酰辅酶A合成增强和呼吸能量代谢增强。这些特性有助于利用丙酮酸或乙酰辅酶A作为前体实现下游产物的高效合成。本文综述了酿酒酵母木糖代谢途径的修饰和优化、木糖代谢的特点以及以木糖为碳源生产化学品的细胞工厂的构建。同时，提出了目前存在的困难和挑战，以及未来以木糖作为重要碳源进行大宗化学品生物合成的研究方向。
