Growth yield of denitrifiers using nitrous oxide as a terminal electron acceptor.

The molar yields (g cell/mol) forAlcaligenes faecalis, Pseudomonas stutzeri, Paracoccus denitrificans andPseudomonas perfectomarinus batch cultures, under nitrous oxide (N2O) as the electron acceptor, were 11.2, 8.2, 6.1 and 4.4, respectively.Paracoccus denitrificans andPseudomonas perfectomarinus, which had the slowest growth rates, gave the lowest yields. Large maintenance energy costs may be partially responsible for this. The growth efficiencies ofA. faecalis andPs. perfectomarinus on N2O indicate that the numbers of sites for oxidative phosphorylation in the electron transport system associated with N2O reduction are about 49% and 39% of those in the electron transport system associated with O2 respiration, respectively.