Elevated conversion of CO to versatile formate by a newly discovered formate dehydrogenase from Rhodobacter aestuarii.

Due to climate change, recent research interests have increased towards CO utilization as a strategy to mitigate the atmospheric CO level. Herein, we aimed to explore formate dehydrogenases (FDHs) from chemoautotroph to discover an efficient and O-tolerant biocatalyst for catalyzing the CO reduction to a versatile formate. Through genome-mining and phylogenetic analysis, the FDH from Rhodobacter aestuarii (RaFDH) was newly discovered as a promising O-tolernat CO reductase and was successfully expressed in Escherichia coli. In this study, the optimum conditions and turnover rates of RaFDH were examined for CO reduction and formate oxidation. In particular, the RaFDH-driven CO reduction far surpassed the formate oxidation with a turnover rate of 48.3 and 15.6 min, respectively. The outstanding superiority of RaFDH towards CO reduction can be applicable for constructing a feasible electroenzymatic system that produce a versatile formate from CO as a cheap, abundant, and renewable resource.