The biosynthesis of cadaverine from lysine is an environmentally promising technology, that could contribute to a more sustainable approach to manufacturing bio‐nylon 5X. However, the titer of biosynthesized cadaverine has still not reached a sufficient level for industrial production. A powerful green cell factory was developed to enhance cadaverine production by regulating lipopolysaccharide (LPS) genes and improving membrane permeability. Firstly, 10 LPS mutant strains were constructed and the effect on the growth was investigated. Then, the lysine decarboxylase (CadA) was overexpressed in 10 LPS mutant strains of Escherichia coli MG1655 and the ability to produce cadaverine was compared. Using 20.0 g L−1 of L‐lysine hydrochloride (L‐lysine‐HCl) as the substrate for the biotransformation reaction, Cad02 and Cad06 strains exhibited high production levels of cadaverine, with 8.95 g L−1 and 7.55 g L−1 respectively while the control strain Cad00 only 4.92 g L−1. Directed evolution of CadA was also used to improve its stability under alkaline conditions. The cadaverine production of the Cad02‐M mutant stain increased by 1.86 times at pH 8.0. Finally, the production process was scaled up using recombinant whole cells as catalysts, achieving a high titer of 211 g L−1 cadaverine (96.8%) by fed‐batch bioconversion. This study demonstrates the potential role of LPS in enhancing the efficiency of mass transfer between substrate and enzymes in vivo by increasing cell permeability. The results indicate that the argumentation of cell permeability could not only significantly enhance the biotransformation efficiency of cadaverine, but also provide a universally applicable, straightforward, environment‐friendly, and cost‐effective method for the biosynthesis of other high‐value chemicals.

中文翻译：

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将定向进化与高细胞渗透性相结合，在工程大肠杆菌中实现高水平尸胺生产

从赖氨酸生物合成尸胺是一项对环境有前景的技术，可能有助于采用更可持续的方法来制造生物尼龙 5X。然而，生物合成尸胺的效价仍未达到足以工业化生产的水平。开发了一个强大的绿色细胞工厂，通过调节脂多糖（LPS）基因和改善膜通透性来提高尸胺产量。首先构建10株LPS突变株并考察其对生长的影响。然后，赖氨酸脱羧酶（CadA）在10个LPS突变株中过表达大肠杆菌与MG1655产生尸胺的能力进行了比较。使用20.0克·升−1以L-赖氨酸盐酸盐（L-lysine-HCl）为底物进行生物转化反应，Cad02和Cad06菌株表现出较高的尸胺产量，产量为8.95 g·L−1和 7.55 克/升−1而对照菌株 Cad00 仅 4.92 g·L−1。CadA 的定向进化也被用来提高其在碱性条件下的稳定性。Cad02-M 突变体染色剂的尸胺产量在 pH 8.0 时增加了 1.86 倍。最后，使用重组全细胞作为催化剂扩大了生产过程，达到了211 g L的高滴度−1通过补料分批生物转化获得尸胺 (96.8%)。这项研究证明了 LPS 通过增加细胞通透性来提高体内底物和酶之间的传质效率的潜在作用。结果表明，细胞渗透性的论证不仅可以显着提高尸胺的生物转化效率，而且还为其他高价值化学品的生物合成提供了一种普遍适用、简单、环境友好且经济有效的方法。