Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, People's Republic of China.
SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
J Ind Microbiol Biotechnol. 2018 Jul;45(7):589-598. doi: 10.1007/s10295-017-1996-y. Epub 2017 Dec 18.
Escherichia coli KO11 is a popular ethanologenic strain, but is more sensitive to ethanol than other producers. Here, an ethanol-tolerant mutant EM was isolated from ultraviolet mutagenesis library of KO11. Comparative genomic analysis added by piecewise knockout strategy and complementation assay revealed EKO11_3023 (espA) within the 36.6-kb deletion from KO11 was the only locus responsible for ethanol sensitivity. Interestingly, when espA was deleted in strain W (the parent strain of KO11), ethanol tolerance was dramatically elevated to the level of espA-free hosts [e.g., MG1655 and BL21(DE3)]. And overexpression of espA in strains MG1655 and BL21(DE3) led to significantly enhanced ethanol sensitivity. In addition to ethanol, deletion of espA also improved cell tolerance to other short-chain (C2-C4) alcohols, including methanol, isopropanol, n-butanol, isobutanol and 2-butanol. Therefore, espA was responsible for short-chain alcohol sensitivity of W-strains compared to other cells, which provides a potential engineering target for alcohols production.
大肠杆菌 KO11 是一种常用的产乙醇菌株，但比其他产乙醇菌对乙醇更敏感。在这里，我们从 KO11 的紫外线诱变文库中分离到一株耐乙醇突变体 EM。通过分段敲除策略和互补实验进行的比较基因组分析表明，KO11 缺失的 36.6kb 片段内的 EKO11_3023（espA）是唯一导致乙醇敏感性的基因座。有趣的是，当 espA 在 W 株（KO11 的亲本株）中缺失时，乙醇耐受性显著提高到无 espA 宿主的水平[例如，MG1655 和 BL21(DE3)]。并且 espA 在 MG1655 和 BL21(DE3)中的过表达导致乙醇敏感性显著增强。除乙醇外，espA 的缺失还提高了细胞对其他短链（C2-C4）醇的耐受性，包括甲醇、异丙醇、正丁醇、异丁醇和 2-丁醇。因此，与其他细胞相比，espA 负责 W 株对短链醇的敏感性，这为醇类生产提供了一个潜在的工程目标。
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