The cyclohexane organic acid 3-dehydroshikimate (DHS) has potent antioxidant activity and is widely utilised in chemical and pharmaceutical industries. However, its production requires a long fermentation with a suboptimal yield and low productivity, and a disproportionate growth-to-production ratio impedes the upscaling of DHS synthesis in microbial cell factories. To overcome these limitations, competing and degradation pathways were knocked-out and key enzymes were balanced in an engineered Escherichia coli production strain, resulting in 12.2 g/L DHS. Furthermore, to achieve equilibrium between cell growth and DHS production, a CRISPRi-based temperature-responsive multi-component repressor system was developed to dynamically control the expression of critical genes (pykF and aroE), resulting in a 30-fold increase in DHS titer. After 33 h fermentation in 5 L bioreactor, the DHS titer, productivity and yield reached 94.2 g/L, 2.8 g/L/h and 55 % glucose conversion, respectively. The results provided valuable insight into the production of DHS and its derivatives.

中文翻译：

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代谢网络重新布线和温度依赖性调节以增强大肠杆菌中 3-脱氢莽草酸的产量


环己烷有机酸3-脱氢莽草酸酯（DHS）具有有效的抗氧化活性，广泛应用于化学和制药行业。然而，其生产需要长时间发酵，产量不理想且生产率低，并且不成比例的生长与生产比阻碍了微生物细胞工厂中 DHS 合成的升级。为了克服这些限制，在工程大肠杆菌生产菌株中消除了竞争和降解途径并平衡了关键酶，从而产生了 12.2 g/L DHS。此外，为了实现细胞生长和 DHS 产生之间的平衡，开发了基于 CRISPRi 的温度响应性多组分阻遏物系统，以动态控制关键基因（pykF 和 aroE）的表达，从而使 DHS 滴度增加 30 倍。在5 L生物反应器中发酵33小时后，DHS效价、生产率和产量分别达到94.2 g/L、2.8 g/L/h和55%葡萄糖转化率。结果为 DHS 及其衍生物的生产提供了宝贵的见解。