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 level. As a CO utilization strategy, formate dehydrogenase (FDH) from Clostridium species were explored to discover O-tolerant and efficient FDHs that can catalyze CO to formate (i.e. CO reductase). With FDH from Clostridium ljungdahlii (ClFDH) that plays as a CO 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 reduction with a specific activity of 15 U g-CaFDH, 17 U g-CcFDH, and 8.7 U g-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 utilization.