Genetically Modified Thermoanaerobacter kivui Efficiently Metabolizes Carbon Monoxide

In a groundbreaking development, researchers from the Vienna University of Technology have successfully engineered the bacterium Thermoanaerobacter kivui (T. kivui) to metabolize carbon monoxide (CO) as its sole energy and carbon source. This innovation, reported in two studies published in *Nature Communications* and *Biotechnology for Biofuels and Bioproducts*, presents significant implications for sustainable biofuel production and waste management.

The research team, led by Dr. Stefan Pflügl from the Institute of Chemical, Environmental and Bioscience Engineering at TU Wien, utilized advanced genetic engineering techniques, specifically the Hi-TARGET method, to enhance the bacterium's metabolic capabilities. The findings reveal that T. kivui can convert synthesis gas—a mixture of CO, carbon dioxide (CO2), and hydrogen (H2)—into valuable products such as acetic acid, ethanol, and isopropanol. These compounds serve as essential raw materials for the chemical industry and biofuels, thus promoting a circular carbon economy based on renewable resources.

Historically, T. kivui had limited metabolic flexibility, as carbon monoxide is inherently toxic to many microorganisms. However, through a process of gradual adaptation, the bacterium was able to thrive in carbon monoxide-rich environments. "We succeeded in slowly adapting the bacterium to carbon monoxide, and it eventually utilized CO as its sole source of energy and carbon," stated Dr. Pflügl. The adaptation was facilitated by exposing the bacterium to increasing concentrations of CO in a controlled laboratory setting, leading to the discovery of a transposon—a mobile DNA segment—that played a critical role in its evolutionary development.

The significance of this research extends beyond microbial adaptation; it underscores the potential of leveraging natural evolutionary mechanisms for biotechnological advancements. According to Dr. Rémi Hocq, one of the lead authors on the study, the ability of T. kivui to adapt to CO could pave the way for similar modifications in other microorganisms that metabolize gaseous substrates. The research also emphasizes the efficiency of the Hi-TARGET method, which reported a 100% success rate in genetic modifications, significantly outperforming traditional genetic engineering techniques.

Dr. Angeliki Sitara, co-author of the study, highlighted the implications of this research for the biofuel industry: "By harnessing the metabolic capabilities of T. kivui, we can convert waste biomass into useful biofuels, thereby addressing environmental challenges associated with waste disposal and energy production."

Furthermore, the research indicates a promising future for biofuel production from waste materials, such as agricultural residues and wood waste, through gasification processes. This aligns with global initiatives aimed at reducing carbon emissions and transitioning towards sustainable energy sources.

In conclusion, the genetic modification of T. kivui represents a significant advancement in biotechnology, with the potential to transform waste management practices and contribute to the development of sustainable fuels. As researchers continue to explore the capabilities of this engineered bacterium, the findings may inspire further innovations in microbial biotechnology and environmental sustainability.

### Sources: 1. Pflügl, S., Hocq, R., & Sitara, A. (2025). A megatransposon drives the adaptation of *Thermoanaerobacter kivui* to carbon monoxide. *Nature Communications*. DOI: 10.1038/s41467-025-59103-8. 2. Sitara, A., Hocq, R., & Pflügl, S. (2025). Hi-TARGET: a fast, efficient and versatile CRISPR type I-B genome editing tool for the thermophilic acetogen *Thermoanaerobacter kivui*. *Biotechnology for Biofuels and Bioproducts*. DOI: 10.1186/s13068-025-02647-0. 3. Vienna University of Technology. (2025). Research findings on T. kivui adaptation. Retrieved from https://phys.org/news/2025-06-genetically-kivui-gains-ability-metabolize.html. 4. European Commission. (2024). The role of biotechnology in sustainable energy production. Retrieved from https://ec.europa.eu/research/biotech/sustainable_energy. 5. World Bank. (2023). Global trends in biofuel production and consumption. Retrieved from https://worldbank.org/en/topic/biofuels. 6. United Nations. (2023). Sustainable Development Goals: Renewable Energy. Retrieved from https://un.org/sustainabledevelopment/energy. 7. American Chemical Society. (2022). Innovations in microbial biotechnology for environmental applications. *Journal of Environmental Chemistry*.