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代谢工程改造无质粒大肠杆菌增强戊二酸合成
首发时间：2025-02-19
摘要：戊二酸是用于生产聚酯和聚酰胺的重要材料单体。目前，发酵法生产戊二酸存在质粒负荷、代谢负担、细胞毒性等问题。基于质粒生产戊二酸的系统在工业应用中存在局限性。因此，本研究构建了一株无质粒的重组大肠杆菌，用于以葡萄糖为原料合成戊二酸。首先在赖氨酸突变菌株中筛选高效和稳定的整合位点，将戊二酸合成途径整合到基因组中，避免了质粒负荷。接着，基于所开发的戊二酸生物传感器，优化限速模块davtd的拷贝数，提升了戊二酸合成效率。此外，通过转录组分析鉴定出潜在戊二酸转运蛋白yide，并将其与赖氨酸转运蛋白lysp的表达进行组合优化，解除了因戊二酸积累而导致的细胞毒性。最后，在5l发酵罐中，菌株ry29戊二酸产量、产率和生产强度分别达到了44.8 g/l，0.28 g/g和0.62g/l/h。
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engineering of plasmid-free e.coli for glutarate biosynthesis
abstract：glutarate is a crucial synthetic precursor for the production of polyesters and polyamides. however, recent studies have predominantly focused on plasmid-based systems for high-level glutarate production, which are impractical for industrial applications. in this study, we aimed to construct a plasmid-free recombinant strain to enhance glutarate biosynthesis from glucose. first, various gene integration sites were characterized to facilitate the chromosomal integration of the glutarate biosynthetic pathway in a lysine-overproducing mutant of e. coli. subsequently, a glutarate biosensor was developed to optimize the rate-limiting davtd module in the glutarate synthetic pathway through copy number optimization. additionally, transcriptome analysis identified a potential glutarate transporter, yide, which was co-expressed with the lysine transporter lysp to further enhance glutarate production. ultimately, in a 5-l fed-batch fermentation, the optimal strain ry29 achieved a glutarate titer of 44.8 g/l, with a yield of 0.28 g/g and a productivity of 0.62 g/l/h. these findings provide valuable insights into the stable production of glutarate in microbial cell factories.
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代谢工程改造无质粒大肠杆菌增强戊二酸合成
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