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Updated: May 8, 2026

CO2 Photoreduction to CH4 Performance Under Concentrating Solar Light
Published on: June 12, 2019
Light driven CO2 fixation by using cyanobacterial photosystem I and NADPH-dependent formate dehydrogenase
Masaki Ihara1, Yusuke Kawano, Miho Urano
1Faculty of Agriculture, Shinshu University, Minamiminowa, Nagano, Japan. m_ihara@shinshu-u.ac.jp
Abstract:
The ultimate goal of this research is to construct a new direct CO2 fixation system using photosystems in living algae. Here, we report light-driven formate production from CO2 by using cyanobacterial photosystem I (PS I). Formate, a chemical hydrogen carrier and important industrial material, can be produced from CO2 by using the reducing power and the catalytic function of formate dehydrogenase (FDH). We created a bacterial FDH mutant that experimentally switched the cofactor specificity from NADH to NADPH, and combined it with an in vitro-reconstituted cyanobacterial light-driven NADPH production system consisting of PS I, ferredoxin (Fd), and ferredoxin-NADP(+)-reductase (FNR). Consequently, light-dependent formate production under a CO2 atmosphere was successfully achieved. In addition, we introduced the NADPH-dependent FDH mutant into heterocysts of the cyanobacterium Anabaena sp. PCC 7120 and demonstrated an increased formate concentration in the cells. These results provide a new possibility for photo-biological CO2 fixation.
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