CuInS2 quantum dots drive Clostridium ljungdahlii photosynthetic catalysis for CO2 reduction to C2 products

Le résumé fourni par la source

Clean fuels (e.g., ethanol) production by anaerobic bacteria that utilize CO 2 as the carbon source and H 2 as the electron donor constitutes a green carbon emission reduction strategy. However, the utilization of CO 2 by bacteria is severely limited due to the low water solubility and slow mass transfer rate of H 2 . In this study, a self-photosensitized CuInS 2 quantum dots (QDs)– Clostridium ljungdahlii hybrid was constructed by integrating efficient photoelectric conversion with stable biological metabolism. CuInS 2 QDs with a band gap of 1.66 eV were employed as photocatalysts to generate photogenerated electrons for replacing H 2 . The hybrid exhibited a three-fold enhancement in photoelectron absorption efficiency compared with pure Clostridium ljungdahlii . In the self-photosensitized cells, the expression level of ferredoxin oxidoreductase, carbon monoxide dehydrogenase, and phosphate acetyltransferase was upregulated by 10%, 36%, and 47%. These changes in metabolites and proteins associated with electron transfer and CO 2 reductive fixation via the Wood-Ljungdahl pathway demonstrated that the bacteria efficiently utilized the extra electrons generated by CuInS 2 QDs. These exogenous electrons strengthened the bacterial capacity to reduce CO 2 into cell-available organic matter, achieving a maximum acetic acid yield of 0.58 g/L and a maximum ethanol yield of 0.21 g/L. Moreover, the hybrid system realized a CO 2 conversion efficiency of 31.7% and a quantum yield of 1.35%. This study confirmed that the electrons generated by CuInS 2 QDs can be transported into bacterial cells and replace H 2 to supply energy for cellular carbon metabolism.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.