Separate Nitrite, Nitric Oxide, and Nitrous Oxide Reducing Fractions from Pseudomonas perfectomarinus

Abstract

Pseudomonas perfectomarinus was found to grow anaerobically at the expense of nitrate, nitrite, or nitrous oxide but not chlorate or nitric oxide. In several repetitive experiments, anaerobic incubation in culture media containing nitrate revealed that an average of 82% of the cells in aerobically grown populations were converted to the capacity for respiration of nitrate. Although they did not form colonies under these conditions, the bacteria synthesized the denitrifying enzymes within 3 hr in the absence of oxygen or another acceptable inorganic oxidant. This was demonstrated by the ability, after anaerobic incubation, of cells and of extracts to reduce nitrite, nitric oxide, and nitrous oxide to nitrogen. From crude extracts of cells grown on nitrate, nitrite, or nitrous oxide, separate complex fractions were obtained that utilized reduced nicotinamide adenine dinucleotide as the source of electrons for the reduction of (i) nitrite to nitric oxide, (ii) nitric oxide to nitrous oxide, and (iii) nitrous oxide to nitrogen. Gas chromatographic analyses revealed that each of these fractions reduced only one of the nitrogenous oxides.

Factors governing the oceanic nitrous oxide distribution: Simulations with an ocean general circulation model

“…The main biological pathways for marine N20 cycling are via nitrification and denitrification processes, as summarized in Figure 1. N20 is produced as an intermediate product in the process of biological denitrification which involves the bacterially mediated multistep reduction of nitrate to nitrogen gas [Payne et al, 1971]. Not all strains of denitrifying bacteria are able to carry this process out to completion and produce N2.…”

Loss of N2O reductase activity as an explanation for poor growth of Pseudomonas aeruginosa on N2O

“…The apparent inability of Pseudomonas aeruginosa to grow on N20 as the sole oxidant has puzzled students of denitrification for the past decade (3,4,16). In contrast, some other denitrifiers that also reduce nitrate to N2, such as P. denitrificans, P. stutzeri, P. perfectomarina, and Paracoccus denitrificans, grow vigorously on exogenous N20 (3, 4, 8,13,19). Bazylinski et al (1) established recently that P. aeruginosa PAO1 and P1 can in fact grow on N20, albeit slowly and to low yield.…”

Cumulative relative reactivity: A concept for modeling aquifer-scale reactive transport

“…The microbes can lie dormant for extended periods of time and then regain their full biodegradation potential within few hours after the end of the starvation period. Other investigations showed that if anaerobic conditions occur, facultative denitrifiers switch from oxygen to nitrate as the electron acceptor within a period of 40 min to 3 h [ Payne and Riley , ; Payne et al ., ; Williams et al ., ]. On the catchment scale, groundwater travel times are generally in the order of several years or decades, and contaminants have been introduced over a long time period so that functionally stable microbial communities have been established, and can be reactivated quickly under dynamic biogeochemical conditions.…”

“…We assume that their microbial turnover depends on the solute concentrations and the release of electron donors from the aquifer matrix. These simplifications seem to be justified as the microbial biomass readily approaches quasi steady state values that hardly change in times of starvation [ Mellage et al ., ; Payne et al ., ]. We consider, however, that denitrification is inhibited in the presence of elevated oxygen concentrations.…”