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Effect of pH, temperature and substrate on N₂O, NO and CO₂ production by Alcaligenes faecalis p
- Kesik, M., Blagodatsky, S., Papen, H., Butterbach-Bahl, K.
- Journal of applied microbiology 2006 v.101 no.3 pp. 655-667
- Alcaligenes faecalis, Paracoccus pantotrophus, carbon dioxide, citrates, environmental factors, gases, microorganisms, models, nitric oxide, nitrous oxide, pH, soil, temperature
- To study the effect of pH, temperature and substrate on the magnitude of N₂O and NO production by heterotrophic nitrifiers. 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. The results indicate that heterotrophic nitrifiers are suitable model organisms to study the influence of environmental factors on microbial N trace gas production. 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.