Presentation Information
[2Biocat-02-KL]From Molecular Tunnels to Molar-Scale Production: Engineering CO Dehydrogenase for the Valorization of Industrial Off-Gases
○Yong Hwan Kim1 (1. UNIST (Korea))
Keywords:
C1 gas,CO dehydrogenase,formate dehydrogenase,CO hydration,formate
[Purpose]
The valorization of carbon monoxide (CO) from industrial flue gases is a critical strategy for sustainable Carbon Capture and Utilization (CCU). However, the practical application of Carbon Monoxide Dehydrogenase (CODH)—nature's most efficient CO-converting catalyst—has been hindered by its intrinsic sensitivity to oxygen (O2) and kinetic limitations with artificial electron mediators. This study aims to overcome these molecular bottlenecks to establish a robust, molar-scale bioprocess for converting real-world steel mill off-gases into formate.
[Method]
We employed a multi-scale engineering strategy. At the molecular level, we utilized computational design to reshape the hydrophobic gas-diffusion tunnels of CODH, creating a selective barrier that blocks O2 while admitting CO. Concurrently, we identified and engineered specific surface residues governing electron mediator interactions to tailor the enzyme’s affinity (Km) and turnover rate. These robust variants were then integrated into a gas-liquid reactor system fed with actual Linz-Donawitz converter gas (LDG).
[Results]
The tunnel-redesigned CODH exhibited remarkable O2 tolerance, maintaining activity in aerobic environments where native enzymes fail. Furthermore, optimizing the mediator interaction spots significantly enhanced electron transfer efficiency. Integrating these innovations, we achieved molar-scale formate production directly from industrial off-gases, demonstrating exceptional stability and productivity despite the presence of gas contaminants.
[Consideration]
The successful scale-up from molecular engineering to molar-scale production indicates that the "fragility" of metalloenzymes is not an insurmountable barrier. It suggests that trade-offs between stability and activity can be decoupled by independently engineering substrate tunnels and electron transfer interfaces.
[Conclusion]
We present a commercially viable biocatalytic platform for converting carbon-rich waste gases into value-added chemicals. This work bridges the gap between protein engineering and sustainable bioprocessing, offering a concrete solution for decarbonizing hard-to-abate heavy industries.
The valorization of carbon monoxide (CO) from industrial flue gases is a critical strategy for sustainable Carbon Capture and Utilization (CCU). However, the practical application of Carbon Monoxide Dehydrogenase (CODH)—nature's most efficient CO-converting catalyst—has been hindered by its intrinsic sensitivity to oxygen (O2) and kinetic limitations with artificial electron mediators. This study aims to overcome these molecular bottlenecks to establish a robust, molar-scale bioprocess for converting real-world steel mill off-gases into formate.
[Method]
We employed a multi-scale engineering strategy. At the molecular level, we utilized computational design to reshape the hydrophobic gas-diffusion tunnels of CODH, creating a selective barrier that blocks O2 while admitting CO. Concurrently, we identified and engineered specific surface residues governing electron mediator interactions to tailor the enzyme’s affinity (Km) and turnover rate. These robust variants were then integrated into a gas-liquid reactor system fed with actual Linz-Donawitz converter gas (LDG).
[Results]
The tunnel-redesigned CODH exhibited remarkable O2 tolerance, maintaining activity in aerobic environments where native enzymes fail. Furthermore, optimizing the mediator interaction spots significantly enhanced electron transfer efficiency. Integrating these innovations, we achieved molar-scale formate production directly from industrial off-gases, demonstrating exceptional stability and productivity despite the presence of gas contaminants.
[Consideration]
The successful scale-up from molecular engineering to molar-scale production indicates that the "fragility" of metalloenzymes is not an insurmountable barrier. It suggests that trade-offs between stability and activity can be decoupled by independently engineering substrate tunnels and electron transfer interfaces.
[Conclusion]
We present a commercially viable biocatalytic platform for converting carbon-rich waste gases into value-added chemicals. This work bridges the gap between protein engineering and sustainable bioprocessing, offering a concrete solution for decarbonizing hard-to-abate heavy industries.
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