Bioelectrocatalytic CO₂ Reduction by Mo-Dependent Formylmethanofuran Dehydrogenase

Area of Science:

• Biocatalysis
• Electrochemistry
• Biotechnology

Background:

• Developing innovative carbon dioxide (CO2) sequestration strategies is crucial for climate change mitigation and CO2 valorization.
• Biological systems offer selective and efficient catalysis for CO2 reduction under mild, aqueous conditions.
• Exploring diverse enzymes beyond formate dehydrogenases is necessary for improved CO2 reduction rates and directionality.

Purpose of the Study:

• To investigate the electroenzymatic catalysis of formylmethanofuran dehydrogenase for CO2 reduction.
• To assess the enzyme's efficiency, selectivity, and potential for CO2 fixation.
• To explore its application in converting CO2 into valuable products like formate.

Main Methods:

• Immobilization of formylmethanofuran dehydrogenase onto a graphite rod electrode for direct electron transfer.
• Direct electroenzymatic reduction of CO2 using the modified electrode.
• Analysis of Faradaic efficiency and product accumulation (formate).

Main Results:

• High Faradaic efficiency (109±1%) for CO2 reduction was achieved.
• The enzyme demonstrated a low affinity for formate, preventing its reoxidation and favoring formate accumulation.
• Successful electroenzymatic CO2 fixation into stable formate was achieved.

Conclusions:

• Formylmethanofuran dehydrogenase is an effective biocatalyst for electroenzymatic CO2 reduction and fixation.
• The enzyme's properties are advantageous for converting CO2 into formate for storage, transport, and energy generation.
• This work provides inspiration for protein engineering to enhance biotechnological CO2 conversion.