Adipic acid is an important dicarboxylic acid, which is an essential building block to synthesize nylon 6-6 fiber. Adipic acid is primarily synthesized from chemical plant, however, this process is associated with a number of environmental concerns including heavy pollution, toxic catalyst and harsh reaction conditions. A decent amount of adipic acid was produced by reconstructing the reversed adipate-degradation pathway (RADP) from Thermobifida fusca in Escherichia coli. However, IPTG was used in the previous study, which was not feasible in the fermentation industry. In this study, strong promoter-5'-UTR complexes (PUTR) were chosen to construct a highly efficient induction-free system to produce adipic acid. First, comparisons of various exogenous 5'-UTR Complexes, as well as a series of E. coli host strains, demonstrated that those genes using E. coli K12 MG1655 as the host strain produced the highest titer of adipic acid. Subsequently, optimizations were applied to enhance the titer of adipate biosynthesizing strains. The highest titer of adipate of 57.6 g L-1 was achieved by fed-batch fermentation. This work offers a better way to enhance the industrial titer of adipate.

中文翻译：

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通过高效无感应系统在大肠杆菌中生物合成己二酸。

己二酸是一种重要的二羧酸，是合成尼龙6-6纤维的重要组成部分。己二酸主要由化工厂合成，但是，此过程与许多环境问题相关，包括重度污染，有毒催化剂和苛刻的反应条件。通过重建大肠杆菌中嗜热栖热菌的反向己二酸降解途径（RADP），可生产适量的己二酸。但是，以前的研究中使用了IPTG，这在发酵工业中是不可行的。在这项研究中，选择了强启动子5'-UTR复合物（PUTR）来构建高效的无诱导体系以生产己二酸。首先，比较各种外源5'-UTR复合物以及一系列大肠杆菌宿主菌株，证明使用大肠杆菌K12 MG1655作为宿主菌株的那些基因产生最高滴度的己二酸。随后，进行优化以提高己二酸酯生物合成菌株的滴度。通过补料分批发酵获得最高的己二酸酯滴度57.6 g L-1。这项工作提供了提高己二酸工业滴度的更好方法。