Characterization of Formate Dehydrogenase of Shewanella amazonensis

Background Members of the family Shewanellacea have the ability to utilise formate as an electron donor for ATP generation under anaerobic respiration. A preliminary study conducted on different strains of Shewanella species shows that the Shewanella amazonensis formate dehydrogenase has a low catalytic activity of formate oxidation, and a high carbon dioxide reductase activity using methyl viologen as an electron acceptor or donor. Objectives The aim of this research was to characterize formate dehydrogenase of Shewanella amazonensis and to investigate its possible use as a biocatalyst for the reduction of CO 2 to formate. The growth phenotypes of Shewanella amazonensis was compared to Shewanella oneidensis on formate under aerobic and anaerobic conditions, and the catalytic properties of the formate dehydrogenase from Shewanella amazonensis were investigated further to better understand the preliminary data. Methods Shewanella amazonensis and Shewanella oneidensis cells were grown aerobically in LB media supplemented with formate. Minimal media supplemented with formate and fumarate was used to study the ability of the strains to utilize formate and fumarate. Methyl viologen was used to study formate oxidation and carbon dioxide reduction using minimal media under anaerobic condition. Results Anaerobic growth on Minimal media supplemented with formate and fumarate suggested that the Shewanella amazonensis growth rate was lower than the growth rate of Shewanella oneidensis . Kinetic assays suggest a lower V max was responsible for the observed kinetic differences.