Catalytic Cooperation between a Copper Oxide Electrocatalyst and a Microbial Community for Microbial Electrosynthesis

Area of Science:

• Biotechnology
• Electrochemistry
• Microbiology

Background:

• Microbial electrosynthesis (MES) utilizes microorganisms for carbon dioxide (CO2) conversion.
• Combining electrocatalytic metals with MES offers potential for enhanced CO2 utilization.
• Systematic investigation of metal-microbe interactions in MES is needed.

Purpose of the Study:

• To investigate the interactions between a copper electrocatalyst and microorganisms in MES for CO2 conversion.
• To understand the co-catalytic and non-metabolic effects of copper on microbial acetate production.
• To assess biofilm formation on copper surfaces within the MES system.

Main Methods:

• Integration of a copper electrocatalyst with microorganisms in an MES setup.
• Monitoring of CO2 conversion to formate by copper and acetate by microorganisms.
• Quantification of formate production, consumption, and acetate yield.
• Analysis of current density changes and biofilm formation.

Main Results:

• A co-catalytic (metabolic) relationship was observed between copper and microorganisms.
• Copper oxide produced up to 140 mg/L of formate; copper also produced and microorganisms consumed formate.
• Non-metabolic interactions led to a >4-fold decrease in current density but a 3.3-fold increase in acetate yield.
• Biofilm formation occurred on the pure copper surface despite its antimicrobial properties.

Conclusions:

• A novel combination of a CO2-reducing copper electrocatalyst with MES under biological conditions was demonstrated.
• Metabolic and non-metabolic interactions significantly influence CO2 conversion efficiency and product yield in this hybrid system.
• Copper electrocatalysts can be successfully integrated with MES, opening avenues for enhanced carbon capture and utilization technologies.