Engineered <i>Escherichia coli</i> Whole Cell-Mediated Electro-Biocatalysis for Carbon Dioxide to Formic Acid Conversion
Hongling Shi, Muran Fu, Shuwei Yuan, Yunfeng Lu, Yang Zhuan, Chao Yue, Lunguang Yao, Chuang Xue, Cun‐Duo Tang
Abstract
The conversion of CO 2 into a valuable chemical fuel could help reduce its effect on global warming. However, the utilization of CO 2 by biological transformations is challenging because of the lack of enzymes exhibiting high catalytic activity toward CO 2 reduction. In this work, three NAD + /W-containing formate dehydrogenases (FDHs) were discovered, expressed, and characterized. In addition, we used Pb FDH, which displays high catalytic activity toward CO 2 reduction, as a biocatalyst to convert CO 2 to formic acid through whole-cell biocatalysis and electro-biocatalysis. The specific activities of Da FDH, Pb FDH, and Cs FDH increased by 68.1, 100.0, and 18.7 times, respectively, compared with that of Cl FDH reported with high catalytic efficiency. Furthermore, this paper presents a preliminary discussion of the catalytic mechanism of FDHs for CO 2 reduction based on their structures. The yield of formic acid obtained from CO 2 reduction using electro-biocatalysis under aerobic conditions reaches up to 4.1 mmol/L/h, without any cofactor NADH and hydrogen gas. This study also demonstrates and compares the performances of NAD + /W-containing and NAD + -dependent FDHs in whole-cell biocatalysis and electro-biocatalysis. The findings of this study provide a meaningful foundation for the conversion of CO 2 into a value-added chemical fuel.