Recent concerns over climate change have triggered many efforts to mitigate atmospheric CO₂ levels. Among the CO₂ utilization strategies, we, herein, aimed to biochemically characterize formate dehydrogenase from Clostridium ljungdahlii (ClFDH) for bioconversion of CO₂ to versatile formate. ClFDH was functionally expressed in Escherichia coli without any accessory proteins and recombinant ClFDH were successfully characterized as CO₂ reductase with a specific activity of 9.1 mU mg⁻¹ for CO₂ reduction. Additionally, the optimum pH was determined at pH 7.0 and 9.0 for CO₂ reduction and formate oxidation, respectively. In particular, ClFDH retain its catalytic activity under aerobic conditions, even if C. ljungdahlii is a representative strict anaerobic microorganism. The results discussed herein would not only contribute to broaden biological routes for CO₂ utilization but also provide significant insight into the valorization of CO₂-containing industrial waste gases to value-added chemicals.

最近对气候变化的担忧引发了许多旨在降低大气 CO ₂水平的努力。在 CO ₂利用策略中，我们在此旨在对杨氏梭菌(ClFDH) 的甲酸脱氢酶进行生物化学表征，以将 CO ₂生物转化为通用甲酸。ClFDH 在没有任何辅助蛋白的情况下在大肠杆菌中功能性表达，并且重组 ClFDH 被成功表征为 CO ₂还原酶，具有 9.1 mU mg ^-1的 CO ₂还原比活性。此外，CO ₂的最佳 pH 值确定为 pH 7.0 和 9.0分别是还原和甲酸氧化。特别是，即使杨氏梭菌是典型的严格厌氧微生物，ClFDH 在有氧条件下仍保持其催化活性。本文讨论的结果不仅有助于拓宽 CO _{2 的}生物利用途径，而且对将含CO ₂的工业废气转化为增值化学品的价值提供重要见解。