Effect of pH, temperature and substrate on N2O, NO and CO2 production by Alcaligenes faecalis p.

Abstract

Aims: To study the effect of pH, temperature and substrate on the magnitude of N2O and NO production by heterotrophic nitrifiers. Methods and Results: The change in N2O and NO production by the heterotrophic nitrifiers Alcaligenes faecalis subsp. parafaecalis and Paracoccus pantotrophus because of variations in pH, temperature and substrate was studied in chemostat cultures under steady‐state conditions. N2O, NO and CO2 production increased with temperature between 4 and 32°C. For N2O an optimum temperature of 28°C was observed. No optimum temperature was found for NO. Highest N2O and CO2 productions were observed at a pH of 7·0. However, besides having an optimum at pH 7·0, especially NO production but also N2O production increased significantly at pH ≤ 4·0. This increase in NO production under acidic conditions was partly because of chemo‐denitrification, which contributed up to 62% of total NO production at pH 3·0 (0·8% for N2O). Furthermore, we could demonstrate that substrate quality significantly affects N2O, NO and CO2 production. N2O and especially NO production by A. faecalis p. was significantly lower on an ammonium citrate medium when compared with rates obtained for a peptone‐meat extract medium. Conclusions: The results indicate that heterotrophic nitrifiers are suitable model organisms to study the influence of environmental factors on microbial N trace gas production. Significance and Impact of the Study: The results allow an improved description, e.g. of the pH dependency of N trace gas production by microbes and/or chemo‐denitrification in process‐oriented models describing the exchange of N trace gases between soils and the atmosphere.

Impact resistance of different factors on ammonia removal by heterotrophic nitrification–aerobic denitrification bacterium Aeromonas sp. HN-02

“…It is well known that the optimal temperature range of heterotrophic nitrification-aerobic denitrification bacteria was 25°C-37°C (Kesik et al, 2006;Taylor et al, 2009;Guo et al, 2013b). According to our experiments, as shown in Fig.…”

Spatial variations of nitrogen trace gas emissions from tropical mountain forests in Nyungwe, Rwanda

“…It is well known that low pH decreases the activity of the N 2 O-reductase, thereby increasing production of N 2 O from denitrification (Nömmik, 1956;Weier and Gillam, 1986;Granli and Bockman, 1994). For nitrification, it has also been demonstrated that low pH values favor N 2 O production (Sitaula and Bakken, 1993;Martikainen and De Boer, 1993;Kesik et al, 2006). Furthermore, it has been shown by Kiese and Butterbach-Bahl (2002) that low pH was a crucial factor driving high N 2 O emissions from coastal lowland soils in an Australian rainforest.…”

Decadal variability of soil CO<sub>2</sub>, NO, N<sub>2</sub>O, and CH<sub>4</sub> fluxes at the Höglwald Forest, Germany

“…This is in line with results of others who found exponential relationships between soil NO fluxes and soil temperatures for agricultural (Williams et al, 1998;Roelle et al, 2001) as well as for forest soils (Van Dijk and Meixner, 2001;Schindlbacher et al, 2004). The strong temperature response of soil NO fluxes at our site may not only be due to the stimulation of nitrification as the assumed main process of NO production at our site , but may also be explained by increasing contributions of NO production by chemo-denitrification in the acidic organic layer (pH of forest floor ≤3.2) at increasing temperatures (Kesik et al, 2006). In agreement with other field and laboratory studies (Smith et al, 1998;Dobbie and Smith, 2001;Schindlbacher et al, 2004), which reported that not only nitric oxide but also nitrous oxide emissions increased exponentially with soil temperature, also our long-term dataset shows that N 2 O emissions increase exponentially with temperature if freeze-thaw periods are excluded.…”