Electrobiocatalytic cascade for bulk reduction of CO2 to CO coupled to fermentative production of high value diamine monomers

Project Information

ECOMO

Grant agreement ID: 101115403

DOI

10.3030/101115403

EC signature date 21 June 2023

Start date 1 November 2023

End date 31 October 2026

Funded under

• The European Innovation Council (EIC)

Total cost

€ 3 784 201,25

EU contribution

€ 3 776 701,25

Coordinated by

TECHNISCHE UNIVERSITAET MUENCHEN
Germany

Periodic Reporting for period 1 - ECOMO (Electrobiocatalytic cascade for bulk reduction of CO2 to CO coupled to fermentative production of high value diamine monomers)

Reporting period: 2023-11-01 to 2024-10-31

Summary of the context and overall objectives of the project

Accessing platform chemicals produced from CO2 and nitrogen through sustainable methods presents a valuable opportunity for innovation. Addressing global demands necessitates collaboration across sectors, utilizing renewable energy alongside CO2 and nature’s catalysts, including enzymes and microbial cells through biotransformation. These natural catalysts function effectively under ambient conditions, facilitating environmentally sustainable solutions. In line with this vision, ECOMO promotes interdisciplinary collaboration, uniting expertise in bioelectrocatalysis, biohybrid materials science, organic synthesis, technical microbiology, and process engineering. The project focuses on three innovation areas: (1) bioelectrochemical conversion of CO2 to CO, (2) microbial gas fermentation of CO to acetate, and (3) metabolic engineering to convert acetate and ammonia into small molecule amines. This strategy aims to produce high-value diamine monomers, which are vital for established polymeric materials like polyamides. ECOMO is dedicated to creating new bio-based and biohybrid modules that integrate seamlessly with existing bioreactor infrastructure to enable specialty chemical production from CO2. The fermentation process uses engineered microbial strains capable of utilizing CO as a carbon source and energy carrier. A noteworthy innovation includes generating CO in situ from CO2 via mediated electron transfer to hydrogel polymer beads containing immobilized CO-dehydrogenase enzymes within acetate-forming bacterial cultures. This advancement harmonizes electrochemical and biocatalytic processes. By effectively demonstrating diamine production, ECOMO diversifies the range of CO2-derived products, increasing the availability of essential chemical building blocks. The initiative focuses on reducing dependence on fossil-derived resources, highlighting its relevance and potential for significant scientific, economic, and societal impact. ECOMO’s innovative approach addresses critical challenges in CO2 and nitrogen management. By aiming for operations near room temperature, it seeks to lower energy requirements compared to conventional industrial methods, such as the Haber-Bosch process for ammonia. The modular sub-technologies developed are anticipated to generate job opportunities, benefiting the economy and society as a whole.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Innovation gate 1: Our project partners from Aix Marseille University, CNRS, France, and Fraunhofer-BC, Straubing, Germany, have successfully produced and isolated Carbon monoxide dehydrogenase (CODH) enzymes from two different microorganisms, namely Thermococcus (Tc-CODH) and Desulfovibrio vulgaris (Dv-CODH). CODH will convert CO2 to carbon monoxide (CO) electrochemically in the framework of ECOMO. The project participants from TUM-EBT have designed and synthesized novel redox-active polymers capable of mediating electron transfer between CODH and CO2. Initial electrochemical studies show successful mediation of electrons from the polymer to CO2 via CODH.
Innovation gate 2: The project participants from the Technical University of Denmark (DTU) have completed the development of microbial consortia adapted to CO and have finalized the planning of all activity tests to indicate how CO-adapted microbial consortia are superior in consuming CO to the non-adapted consortia. The microbial consortia showed a high selectivity for acetic acid production under the enrichment conditions. The development of electron mediating consortia will occur with CO-adapted consortia as starting inoculum and is expected to be completed very soon. The DTU partners have also started up two trickle bed reactors, TBR, and adapted them for CO, while they have started optimization tests towards achieving higher selectivity. Operation of trickle bed reactors and adaptation to CO showed a selectivity for acetate lying between 76 – 90 %. An optimization strategy for increasing the acetate selectivity of the acetate switch, including the elimination of micronutrients necessary for ethanol generation, in-situ acetate removal, and operation at thermophilic temperature, is expected to boost the selectivity and reach the KPI (Key Performance Indicator) of 95% acetate selectivity.
Innovation gate 3: The work of the third innovation gate of ECOMO aims at the renewable production of plastic polymer precursors such as diamines and diols from CO--2-derived acetate provided by innovation gates 1 and 2 and recycled nitrogen flows. The commonly established industrial host microorganism Corynebacterium glutamicum fermentatively produces the industrially important and useful monomers. The TUM-MIB and Fraunhofer-SCP project partners focused on several tasks to jointly generate new and optimized available production strains for high production performance on acetate. Therefore, the genetic toolbox of C. glutamicum was extended to facilitate more efficient construction of high-yielding strains. Moreover, based on computer-generated predictions, a compressed metabolic model of the organism’s core metabolism was built and used to simulate diol and diamine production and direct strain construction. Also, available first-generation diamine producers were adapted for production on acetate, and initial producer strains are now ready for early-stage scale-up experiments and process development.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The results at the current stage of ECOMO go beyond the state-of-the-art and are summarised below.
Innovation gate 1: Previous redox-active polymers synthesized by the project partner TUM-EBT exhibited reduction potentials of -0.25 V and -0.4 V versus SHE, which are too positive to mediate electrons for CO2 reduction by CODH enzymes. With the design and successful synthesis of novel redox-active polymers with reduction potentials negative enough to mediate electrons between the CODH enzyme and CO2 in a CO2 electrolyzer, the project is advancing forward in the realm of bioelectrochemical CO2 reduction
Innovation gate 2: Reaching the KPI of 95% acetate selectivity is expected to boost further application of mixed microbial consortia-based gas fermentations, which nowadays is limited to methane production at industrial scale. Demonstrating production of acetate from CO with high selectivity by mixed microbial consortia will constitute a significant scientific impact – especially as CO is a well-known substrate favoring ethanol production in gas fermentations.
Innovation gate 3: Corynebacterium glutamicum was enabled to produce a diamine from acetate using metabolic engineering. The substrate spectrum of available diamine producer strains was extended to acetate as carbon source by rewiring the central metabolism. Within the ECOMO cascade acetate has high potential to be produced regeneratively directly from CO2. Thereby, a sustainable/carbon neutral feedstock for diamine production can be delivered. To complete the ECOMO process cascade and fully achieve the regenerative production of diamines from CO2 and recycled nitrogen flows, further research is needed.

Overall material flow in ECOMO