Koma Daisuke, Kishida Takahiro, Yamanaka Hayato, Moriyoshi Kunihiko, Nagamori Eiji, Ohmoto Takashi
Osaka Research Institute of Industrial Science and Technology, 1-6-50 Morinomiya, Joto-ku, Osaka 536-8553, Japan.
Department of Biomedical Engineering, Faculty of Engineering, Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka 535-8585, Japan.
J Biosci Bioeng. 2018 Nov;126(5):586-595. doi: 10.1016/j.jbiosc.2018.05.014. Epub 2018 Jun 28.
Many metabolic engineering approaches have been attempted to generate strains capable of producing valuable compounds. One of main goals is industrial application of these strains. Integration of synthetic pathway genes into the Escherichia coli chromosome enables generation of a plasmid-free strain that is stable and useful for industrial applications. Strains that do not require induction are advantageous in terms of cost. In the present study, we constructed a constitutive overexpression system in E. coli to generate plasmid-free and inducer-free strains. The T7 RNA polymerase/T7 promoter overexpression system, which is an isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible gene overexpression system (T7-dependent inducible overexpression system), was modified to be a constitutive overexpression system. The constructed overexpression system, a "chromosome-based T7-dependent constitutive overexpression system", was applied in a metabolic engineering study to generate a plasmid-free and inducer-free phenylalanine producing strain of E. coli.
许多代谢工程方法已被尝试用于构建能够产生有价值化合物的菌株。主要目标之一是这些菌株的工业应用。将合成途径基因整合到大肠杆菌染色体中能够产生无质粒菌株，该菌株稳定且适用于工业应用。不需要诱导的菌株在成本方面具有优势。在本研究中，我们在大肠杆菌中构建了一个组成型过表达系统，以产生无质粒且无需诱导剂的菌株。T7 RNA聚合酶/T7启动子过表达系统，即异丙基-β-D-硫代半乳糖苷（IPTG）诱导型基因过表达系统（T7依赖性诱导型过表达系统），被改造为组成型过表达系统。构建的过表达系统，即“基于染色体的T7依赖性组成型过表达系统”，被应用于代谢工程研究中，以产生无质粒且无需诱导剂的产苯丙氨酸大肠杆菌菌株。
