[P005] Poster

12:10 PM - 1:00 PM JST(3:10 AM - 4:00 AM UTC)

[P03-305] Identification and Characterization of Novel-CO₂-utilizing Acetogenic Bacteria Isolated from Domestic Habitats

○Donghwi Lee¹, Seulgi Kang¹, Jiyun Bae¹, Chanho Park^2,1, Hyunwoo Jung², Jejin Kim², Minkoo Jung², You-Jung Jung³, Hyeokjun Yoon³, Moonsuk Hur³, Kyungjin Lee³, Suhyung Cho^1,4, Byung-Kwan Cho^2,4 (1. Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea (Korea), 2. Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea (Korea), 3. Biological and Genetic Resources Assessment Division, National Institute of Biological Resources, Incheon, Korea (Korea), 4. KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea (Korea))

Keywords:

Acetogenic bacteria,Wood-Ljungdahl pathway,Carbon dioxide,Genome sequencing

Acetogenic bacteria (acetogens) are the specialized group of anaerobic bacteria that can assimilate C1 feedstocks, such as carbon dioxide (CO₂), carbon monoxide, and methanol, for their autotrophic growth. Acetogens utilize a distinct carbon fixation system, the Wood-Ljungdahl (WL) pathway, through which they can fix CO₂ into acetyl-CoA and acetate. With the C1 fixation capability, they have powerful potential as biocatalysts to produce value-added biochemicals from various C1 substrates, such as ethanol and 2,3-butanediol. So far, over 100 acetogen species exist, and interestingly, genes encoding the WL pathway have significant differences among species, indicating various CO₂-fixing efficiencies. To identify novel CO₂-fixing bacteria, we isolated 246 anaerobic bacteria from various domestic habitats and selected 31 acetogen candidates based on their growth rates and acetate productions under H₂/CO₂ autotrophic conditions. Furthermore, the carbon flux toward WL pathways was also confirmed through ¹³C isotope-labeling analysis. Based on our results, we selected five acetogen candidates that showed higher or similar CO₂-fixation capabilities when compared to model acetogens and other candidates. For further characterization, whole genome sequencing was performed on the PacBio and Illumina platforms. Genome sequencing revealed energy modules and carbon-fixation pathways analogous to those in other acetogens, as well as unique genetic traits conferring high carbon-fixation efficiency. Finally, AC18, which showed the highest CO₂-fixation capability, was selected, and detailed phenotypic analysis under optimized culture conditions for AC18 was conducted. Based on these genomic and phenotypic insights, our current efforts are focused on the development of engineering platforms for this novel acetogen strain. Our final goal is to further maximize its CO₂-fixation efficiency and productivity for industrial applications. We believe these comprehensive results encourage the development of highly efficient CO₂-fixing biocatalysts for the reduction of greenhouse gas emissions.

This work was supported by a grant from the National Institute of Biological Resources (NIBR), funded by the Ministry of Environment (MOE) of the Republic of Korea (NIBR202522201), and from the Korea Environmental Industry & Technology Institute (KEITI) through Technology Development Program for CO₂ Mitigation and Conversion to Value-Added Products Using Indigenous Organism, funded by Korea Ministry of Climate, Energy and Environment (MCEE) (RS-2026-25505528).