Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 west 7th Avenue, Tianjin Airport Economic Area, Tianjin, China.
University of Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2024 Nov 17;15(1):9962. doi: 10.1038/s41467-024-53946-3.
Electrocatalytic carbon dioxide (CO) reduction by CO reductases is a promising approach for biomanufacturing. Among all known biological or chemical catalysts, hydrogen-dependent carbon dioxide reductase from Thermoanaerobacter kivui (TkHDCR) possesses the highest activity toward CO reduction. Herein, we engineer TkHDCR to generate an electro-responsive carbon dioxide reductase considering the safety and convenience. To achieve this purpose, a recombinant Escherichia coli TkHDCR overexpression system is established. The formate dehydrogenase is obtained via subunit truncation and rational design, which enables direct electron transfer (DET)-type bioelectrocatalysis with a near-zero overpotential. By applying a constant voltage of -500 mV (vs. SHE) to a mediated electrolytic cell, 22.8 ± 1.6 mM formate is synthesized in 16 h with an average production rate of 7.1 ± 0.5 μmol hcm, a Faradaic efficiency of 98.9% and a half-cell energy efficiency of 94.4%. This study provides an enzyme candidate for high efficient CO reduction and opens up a way to develop paradigm for CO-based bio-manufacturing.
通过 CO 还原酶电催化二氧化碳（CO）还原是生物制造的一种很有前途的方法。在所有已知的生物或化学催化剂中，来源于热厌氧菌（Thermoanaerobacter kivui）的氢依赖型二氧化碳还原酶（TkHDCR）对 CO 还原具有最高的活性。在此，我们考虑到安全性和便利性，对 TkHDCR 进行工程改造，以生成一种对 CO 还原具有电响应的酶。为此，我们建立了一个重组大肠杆菌 TkHDCR 过表达系统。通过亚基截断和合理设计获得了甲酸脱氢酶，其能够进行直接电子转移（DET）型生物电催化，具有接近零的过电势。通过在介导的电解池中施加-500 mV（相对于 SHE）的恒电压，在 16 小时内合成了 22.8 ± 1.6 mM 的甲酸，平均产率为 7.1 ± 0.5 μmol hcm，法拉第效率为 98.9%，半电池能量效率为 94.4%。本研究为高效 CO 还原提供了一种酶候选物，并为基于 CO 的生物制造开辟了一种范例。
