Systems approaches for enhancing the utilization of carbon dioxide in Acetogens아세토젠의 이산화탄소 활용 능력 향상을 위한 시스템적 접근

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Acetogenic bacteria are responsible for the fixation of about 20% of $CO_2$ in the earth. Due to this physiological trait, acetogens have been used as attractive biocatalysts for gas fermentation of synthesis gas (CO, $H_2$, and $CO_2$) produced from a steel mill or biomass gasification. However, the approach has several major limitations, such as the narrow product spectrum and low product titers. In this study, I utilized systematic approaches to interpret the acetogenesis process and to develop genetic tools for acetogens. First, I present the three complete genomes of acetogens and elucidated core genes associated with $CO_2$ utilization through a comparative analysis of 14 diverse acetogen genomes. Second, I elucidated the transcriptome of mesophilic and psychrotolerant acetogens under diverse growth conditions. The transcriptomic data revealed 5'-UTRs control the RNA abundance of the acetogenesis genes at low-temperature in psychrotolerant acetogen. Third, I systematically analyzed the gene expression of the model acetogen at both transcriptional and translational levels. The study revealed that the Wood–Ljungdahl pathway is significantly regulated at the translation level according to growth conditions. Also, the multi-omics data revealed that the glycine cleavage system cooperates with the Wood-Ljungdahl pathway to participate in $CO_2$ fixation and redox balancing. Finally, I developed suitable plasmid and promoter systems that enable the implementation of the acetoin biosynthetic pathway for the production of acetoin from $CO_2$-$H_2$. Based on the CRISPR-Cas9 system, I demonstrated the Wood-Ljungdahl pathway is essential for autotrophic growth. Furthermore, through genomic engineering with the glycine cleavage system derived from other acetogens, the $CO_2$ utilization capacity of Eubacterium limosum could be increased more than 2 times under both fructose and $CO_2$-$H_2$ conditions. Therefore, systems and synthetic biology approaches provide the opportunity to enhance the holistic understanding of acetogenesis and the efficient utilization of $CO_2$ in acetogens.
Advisors
Cho, Byung-Kwanresearcher조병관researcher
Description
한국과학기술원 :생명과학과,
Publisher
한국과학기술원
Issue Date
2020
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 생명과학과, 2020.8,[vi, 198 p. :]

Keywords

이산화탄소 고정▼a아세토젠▼a합성가스발효▼a시스템생물학▼a합성생물학; $CO_2$ fixation▼aAcetogen▼aSyngas fermentation▼aSystems Biology▼aSynthetic Biology

URI
http://hdl.handle.net/10203/284423
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=924488&flag=dissertation
Appears in Collection
BS-Theses_Ph.D.(박사논문)
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