Kinetics of H₂oxidation in respiring and denitrifyingParacoccus denitrificans

Paracoccus denitrificans: oxidized H2 with O2, nitrate, nitrite or nitrous oxide as electron acceptor. The electron acceptors did not significantly affect threshold, Km or Vmax of H2 oxidation which were on the average 0.83 ppmv H2 (0.5 nM), 1565 ppmv H2 (1 μM), and 3.63 fmol H2 h−1 cell−1, respectively. P. denitrificans was unable to oxidize H2 at the low mixing ratios present in the ambient atmosphere under both respiring and denitrifying conditions.