HYDROGEN METABOLISM IN ACETOBACTER PEROXYDANS

Abstract

Intact cells of A. peroxydans reduce O2 and H2O2, but not methylene blue (MB), at the expense of H2; cell-free preparations reduce O2 and MB, but not H2O2. Hydrog-enase activity is found nearly exclusively in particles. Di- and triphosphopyridine nucleotide (DPN+ and TPN+) are not reduced by H2 in cell-free preparations, which reduce DPN+ with ethanol and reduce TPN+ with citrate or glucose-6-phosphate. H2 and ethanol appear to compete for a terminal electron acceptor system. Spectrophotometric evidence suggests the presence of cytochrome b in extracts. Formate is oxidized to CO2 and H2O, and formic dehydrogenase is present, but no formic hydrogenlyase activity was demonstrated.