Adapting gas fermenting bacteria for light-driven domino valorization of CO2

Abstract

The solar-driven valorization of CO2 to fuels and chemicals provides an exciting opportunity to develop a circular chemical industry, but the controlled production of multicarbon organics remains a major challenge. Here, we present an abiotic–biotic domino strategy that integrates a photocatalytic CO2-to-syngas conversion system with evolved syngas-fermenting bacteria to enable the upcycling of CO2 into valuable C2 products, including acetate and ethanol. To optimize microbial syngas fermentation through an accessible and chemist-friendly platform, we employ adaptive laboratory evolution (ALE) of Clostridium ljungdahlii (Cl). The adapted strain, Cladapt, exhibits a 2.5-fold increase in growth rate and a 120-fold enhancement in C2 production compared to the wild type (Clwt). Isotopic labeling confirmed Cladapt's high conversion efficiency, yielding 6 : 1 and 9 : 1 ratios of 13C : 12C in acetate and ethanol, respectively. Whole genome sequencing revealed mutations in Cladapt, offering initial clues to its enhanced metabolism. A scaled-up semiconductor-molecule hybrid photocatalyst, TiO2|phosphonated Co(terpyridine)2, was employed to generate sufficient syngas (CO/H2 ratio: ∼30 : 70 with 1.3 mmol of CO after 6 days) for Cladapt to demonstrate photocatalytic CO2 → syngas → C2 conversion (yielding 0.46 ± 0.07 mM, or 3.2 μmol, of acetate). This study offers a streamlined approach to improving syngas fermentation in Cl, insights into microbial adaptability, and an ALE-guided pathway for solar-powered CO2 upcycling using an inorganic-microbial domino strategy.

Graphical abstract: Adapting gas fermenting bacteria for light-driven domino valorization of CO2

Supplementary files

Article information

Article type
Edge Article
Submitted
28 Phe 2025
Accepted
10 Mot 2025
First published
12 Mot 2025
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2025, Advance Article

Adapting gas fermenting bacteria for light-driven domino valorization of CO2

L. Su, S. Rodríguez-Jiménez, M. I. M. Short and E. Reisner, Chem. Sci., 2025, Advance Article , DOI: 10.1039/D5SC00764J

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