Periodic Reporting for period 1 - BIOELECTRO-CO2 (Bioelectrochemical transformation of CO2 for the synthesis of value-added products)
Berichtszeitraum: 2023-03-01 bis 2025-02-28
The BIOELECTRO-CO2 project addresses the urgent need for innovative solutions to mitigate greenhouse gas emissions, particularly CO2. With greenhouse gases on the rise, this project focuses on reducing CO2 emissions through microbial electrosynthesis (MES), a technique utilizing microorganisms to convert chemical waste into sustainable chemical commodities. Unlike conventional MES systems that rely on bicarbonate (due to the low solubility of CO2 in water), the BIOELECTRO-CO2 project has developed an advanced approach that directly uses CO2 as a feedstock by implementing a dual bio-catalyzed MES system. A key innovation is the use of gas diffusion electrodes (GDEs) to enhance CO2 uptake, overcoming the problem of its low solubility in water. Another key feature is the integration of a specially designed biocatalyzed anode that oxidizes glycerol, a byproduct of biodiesel production, to generate energy for the MES system while producing valuable chemical byproducts. This dual functionality not only maximizes resource use but also adds significant sustainability benefits by converting waste materials into useful products. By advancing CO2 reduction technologies and encouraging renewable chemical production, BIOELECTRO-CO2 has the potential to make a meaningful contribution to climate change mitigation and sustainable resource transformation at scale.
Primary technical activities focused on testing GDEs for effective CO2 capture, selecting appropriate biocatalysts for both the bioanode and biocathode, and developing a prototype MES system. To achieve this, a number of gas-diffusion bioelectrodes (GDBs) was tested, promoting stable biofilm growth and bio-electrochemical CO2 conversion. The project team also optimized a bioanode specifically for glycerol oxidation, enhancing the MES’s overall functionality. Bioelectrochemical tests, including cyclic voltammetry and chronoamperometry, revealed increased current densities and intensified redox peaks, suggesting heightened electrocatalytic activity with CO2-based MES. High-performance liquid chromatography (HPLC) confirmed increased production of volatile fatty acids (VFAs), particularly of acetate, propionate, and butyrate, demonstrating improved CO2 conversion into valuable chemicals. The key outcome was the improvement in current density and stability of MES systems fed with CO2 compared to those using bicarbonate, indicating enhanced system efficiency. Microbial enrichment and community analyses were conducted to better understand biofilm dynamics. The integrated dual bio-catalytic MES system has successfully merged CO2 reduction with glycerol oxidation, establishing a foundational technology for efficient CO2 transformation. The integrated bio-catalytic MES system was implemented, achieving a combination of CO2-reducing and glycerol-oxidizing functionalities.
A key innovation in this project is the use of GDEs, which facilitate more efficient CO2 transfer and bioavailability within the MES system, allowing for improved conversion rates and enhanced system performance. This gas diffusion electrode technology allows CO2 to permeate directly into the microbial system, circumventing the limitations of low CO2 solubility and enabling microorganisms to more effectively process CO2 into bio-based chemicals. Additionally, the BIOELECTRO-CO2 system incorporates a specially designed biocatalyzed anode that utilizes glycerol—a byproduct of biodiesel production—as a secondary feedstock. This biocatalytic anode serves a dual purpose: it generates energy to drive the system and concurrently produces value-added chemicals, further enhancing the sustainability and efficiency of the system. Using GDEs to enhance CO2 bioavailability, the project has significantly improved current density and VFAs production, underscoring the system’s efficiency in chemical production. The GDB supports robust biofilm growth and optimized electron transfer, while the glycerol-oxidizing bioanode offers a scalable pathway for converting waste into high-value products. This innovative system represents a viable solution for both carbon sequestration and bio-based commodity production, supporting a sustainable, circular economy. By successfully merging CO2-reducing and glycerol-oxidizing functionalities in a single system, the BIOELECTRO-CO2 project has developed a foundational technology that can contribute to broader climate change mitigation goals while promoting sustainable chemical production from renewable and waste-based resources.