Conversion of Escherichia coli into Mixotrophic CO2 Assimilation with Malate and Hydrogen Based on Recombinant Expression of 2-Oxoglutarate:Ferredoxin Oxidoreductase Using Adaptive Laboratory Evolution
We report the mixotrophic growth of Escherichia coli based on recombinant 2-oxoglutarate:ferredoxin oxidoreductase (OGOR) to assimilate CO2 using malate as an auxiliary carbon source and hydrogen as an energy source. OGOR enzyme and tricarboxylic cycle with glyoxylate bypass in E. coli. For OGOR reaction, one CO2 molecule is assimilated, and succinyl-CoA is converted to 2-oxoglutarate. for We employ anaerobic bioreactor for a long-term adaptive evolution to convert heterotrophic E. coli into mixotrophic E. coli.
Sustainable Development Goals
Abstract/Objectives
The research discusses the mixotrophic growth of *Escherichia coli* through the introduction of recombinant 2-oxoglutarate:ferredoxin oxidoreductase (OGOR), enabling the bacterium to assimilate CO2 using malate as a supplementary carbon source and hydrogen for energy. A long-term, approximately 184-day, two-stage adaptive evolution was employed to transform heterotrophic *E. coli* into a mixotrophic variant. In the first phase, using serine, diauxic growth was observed, while in the second phase with malate, the evolved strain successfully grew in a mixotrophic manner, relying on CO2 as a crucial growth substrate. This research aims to enhance the potential applications of OGOR in microbial CO2 assimilation and future hydrogen-based electro-microbial processes.
Results/Contributions
We report the mixotrophic growth of Escherichia coli based on recombinant 2-oxoglutarate:ferredoxin oxidoreductase (OGOR) to assimilate CO2 using malate as an auxiliary carbon source and hydrogen as an energy source. We employ a long-term (~184 days) two-stage adaptive evolution to convert heterotrophic E. coli into mixotrophic E. coli. In the first stage of evolution with serine, diauxic growth emerges as a prominent feature. At the end of the second stage of evolution with malate, the strain exhibits mixotrophy with CO2 as an essential substrate for growth. We expect this work will open new possibilities in the utilization of OGOR for microbial CO2 assimilation and future hydrogen-based electro-microbial conversion.
Keywords
carbon fixationreductive tricarboxylic acid cycle2-oxoglutarate:ferredoxin oxidoreductaseadaptive laboratory evolution
Contact Information
楊雅棠
ytyang@ee.nthu.edu.tw