2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable pseudo-aromatic dicarboxylic acid, is a promising building block compound for manufacturing biodegradable polyesters. This study aimed to construct high-performance cell factories enabling the efficient production of PDC from glucose. Firstly, the effective enzymes of the PDC biosynthetic pathway were overexpressed on the chromosome of the 3-dehydroshikimate overproducing strain. Consequently, the one-step biosynthesis of PDC from glucose was achieved. Further, the PDC production was enhanced by multi-copy integration of the key gene encoding 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase and co-expression of hemoglobin. Subsequently, the PDC production was substantially improved by redistributing the metabolic flux for cell growth and PDC biosynthesis based on dynamically downregulating the expression of pyruvate kinase. The resultant strain PDC50 produced 129.37 g/L PDC from glucose within 78 h under fed-batch fermentation conditions, with a yield of 0.528 mol/mol and an average productivity of 1.65 g/L/h. The findings of this study lay the foundation for the potential industrial production of PDC.

中文翻译：

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大肠杆菌代谢工程高水平生产可生物降解聚酯单体2-吡喃酮-4,6-二甲酸

2-吡喃酮-4,6-二羧酸 (PDC) 是一种化学稳定的假芳香族二羧酸，是一种有前途的用于制造可生物降解聚酯的结构单元化合物。本研究旨在构建高性能细胞工厂，从而能够利用葡萄糖高效生产 PDC。首先，PDC生物合成途径的有效酶在3-脱氢莽草酸过量生产菌株的染色体上过量表达。由此，实现了从葡萄糖一步生物合成PDC。此外，通过编码4-羧基-2-羟基粘康酸-6-半醛脱氢酶的关键基因的多拷贝整合和血红蛋白的共表达，增强了PDC的产生。随后，基于动态下调丙酮酸激酶的表达，通过重新分配细胞生长和PDC生物合成的代谢流，显着提高了PDC的产量。所得菌株PDC50在分批补料发酵条件下，在78 h内以葡萄糖为原料生产129.37 g/L PDC，产量为0.528 mol/mol，平均产率为1.65 g/L/h。本研究结果为PDC的工业化生产奠定了基础。