Newly explored formate dehydrogenases from Clostridium species catalyze carbon dioxide to formate.

With concerns over global warming and climate change, many efforts have been devoted to mitigate atmospheric CO 2 level. As a CO 2 utilization strategy, formate dehydrogenase (FDH) from Clostridium species were explored to discover O 2 -tolerant and efficient FDHs that can catalyze CO 2 to formate (i.e. CO 2 reductase). With FDH from Clostridium ljungdahlii (ClFDH) that plays as a CO 2 reductase previously reported as the reference, FDH from C.autoethanogenum (CaFDH), C. coskatii (CcFDH), and C. ragsdalei (CrFDH) were newly discovered via genome-mining. The FDHs were expressed in Escherichia coli and the recombinant FDHs successfully catalyzed CO 2 reduction with a specific activity of 15 U g -1 -CaFDH, 17 U g -1 -CcFDH, and 8.7 U g -1 -CrFDH. Interestingly, all FDHs newly discovered retain their catalytic activity under aerobic condition, although Clostridium species are strict anaerobe. The results discussed herein can contribute to biocatalytic CO 2 utilization.

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