One-step transformation of CO2 to methane by Escherichia coli with a synthetic biomethanation module.

The biomethanation process is widely recognized as a significant approach to mitigating carbon dioxide emissions while simultaneously generating methane. However, only a few microorganisms that required intricate culturing conditions were identified for biomethanation. Here, Escherichia coli that featured easy cultivation and versatile chassis was genetically modified for biomethanation for the first time. The nif-related gene cluster with methanogenic capability from Rhodopseudomonas palustris was systematically analyzed, cloned, and integrated into a synthetic biomethanation module. As a result, E. coli BL21 (DE3) and Rosetta (DE3) carrying this synthetic biomethanation module exhibited significant methane production activity, with methane yields reaching 50 nmol/mL and 159 nmol/mL, respectively. This finding provided a simple route to construct synthetic strain for biomethanation, which would advance the fundamental research and be beneficial to further harness the power of biomethanation for practical application.