Species Coexistence in Nitrifying Chemostats: A Model of Microbial Interactions

• Published in: Processes Vol. 4; no. 4; p. 51
• Main Authors: Dumont, Maxime, Godon, Jean-Jacques, Harmand, Jérôme
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.12.2016; MDPI
• Subjects: Ammonia; Ammonium; Bacteria; Chemostats; Coexistence; Competition; Functions (mathematics); Life Sciences; Mathematical analysis; Mathematical models; Microorganisms; Monitoring; Nitrification; Nitrite; Nitrites; Nitrogen; Oxidation; competitive exclusion principle; phylotype; modèle mathématique; coexistence; nitrifying bacteria; ammonium; microbial interactions; interaction microbienne; chemostat; ecosystem functions; nitrite; mathematical model; bactérie nitrifiante; chemostat models; azote soluble
• ISSN: 2227-9717; 2227-9717
• DOI: 10.3390/pr4040051

In a previous study, the two nitrifying functions (ammonia oxidizing bacteria (AOB) or nitrite-oxidizing bacteria (NOB)) of a nitrification reactor-operated continuously over 525 days with varying inputs-were assigned using a mathematical modeling approach together with the monitoring of bacterial phylotypes. Based on these theoretical identifications, we develop here a chemostat model that does not explicitly include only the resources’ dynamics (different forms of soluble nitrogen) but also explicitly takes into account microbial inter- and intra-species interactions for the four dominant phylotypes detected in the chemostat. A comparison of the models obtained with and without interactions has shown that such interactions permit the coexistence of two competing ammonium-oxidizing bacteria and two competing nitrite-oxidizing bacteria in competition for ammonium and nitrite, respectively. These interactions are analyzed and discussed.