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Abstract:
Little is known about the growth of formate dehydrogenase-lacking acetogen on formate as sole carbon source. Here, we analyzed formate metabolism in Clostridium bovifaecis strain BXX using different concentrations of formate. The results show that C. bovifaecis converted formate (11.5-96 mM) into acetate with molar ratio of 2.0:1~2.6:1 by using L-cysteine in the anaerobic medium as electron source according to the stoichiometry of acetogenesis. Genome analysis of C. bovifaecis revealed genes encoding anaerobic ribonucleoside triphosphate reductase (nrdD and nrdG) catalyzing the oxidation of formate to CO2 while ATP is being reduced to the desoxy form. The existence of nrdD was verified by PCR, reverse transcription-PCR analysis and acetogenesis from formate. The process mode of acetogenesis from formate in C. bovifaecis provides insight into the unique metabolic feature of an FDH-lacking acetogen.