Department of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China; William G. Lowrie Department of Chemical & Biomolecular Engineering, The Ohio State University, 151 West Woodruff Ave, Columbus, OH 43210, USA.
William G. Lowrie Department of Chemical & Biomolecular Engineering, The Ohio State University, 151 West Woodruff Ave, Columbus, OH 43210, USA; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Bioresour Technol. 2019 Jul;284:415-423. doi: 10.1016/j.biortech.2019.03.145. Epub 2019 Mar 30.
Clostridium carboxidivorans can convert CO, CO and H to ethanol and n-butanol; however, its industrial application is limited by the lack of tools for metabolic pathway engineering. In this study, C. carboxidivorans was successfully engineered to overexpress aor, adhE2, and fnr together with adhE2 or aor. In glucose fermentation, all engineered strains showed higher alcohol yields compared to the wild-type. Strains overexpressing aor showed CO re-assimilation during heterotrophic growth. In syngas fermentation, compared to the wild-type, the strain overexpressing adhE2 produced ∼50% more ethanol and the strain overexpressing adhE2 and fnr produced ∼18% more butanol and ∼22% more ethanol. Interestingly, both strains showed obvious acid re-assimilation, with <0.15 g/L total acid remaining at the end of fermentation. Overexpressing fnr with adhE2 enhanced butanol production compared to only adhE2. This is the first report of overexpressing homologous and heterologous genes in C. carboxidivorans for enhancing alcohols production from syngas and glucose.
梭菌可以将 CO、CO 和 H 转化为乙醇和正丁醇；然而，其工业应用受到缺乏代谢途径工程工具的限制。在本研究中，成功地对梭菌进行了工程改造，以过表达 aor、adhE2 和 fnr 以及 adhE2 或 aor。在葡萄糖发酵中，所有工程菌株的酒精产率均高于野生型。过表达 aor 的菌株在异养生长过程中表现出 CO 再同化。在合成气发酵中，与野生型相比，过表达 adhE2 的菌株产生了约 50%更多的乙醇，而过表达 adhE2 和 fnr 的菌株产生了约 18%更多的正丁醇和约 22%更多的乙醇。有趣的是，两种菌株都表现出明显的酸再同化，发酵结束时总酸残留量<0.15 g/L。与仅过表达 adhE2 相比，与 fnr 共过表达 adhE2 增强了丁醇的生产。这是首次报道在梭菌中过表达同源和异源基因以增强合成气和葡萄糖生产醇的报道。
