Open AccessCompetition between two nitrite‐oxidizing bacterial populations: a model for studying the impact of wastewater treatment plant discharge on nitrification in sediment
Author(s) -
Féray Christine,
Montuelle Bernard
Publication year - 2002
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2002.tb00991.x
Subject(s) - biology , nitrite , nitrification , effluent , nitrobacter , heterotroph , autotroph , wastewater , microbiology and biotechnology , strain (injury) , sediment , sewage treatment , environmental chemistry , botany , ecology , bacteria , nitrate , environmental engineering , nitrogen , chemistry , paleontology , genetics , organic chemistry , anatomy , engineering
Nitrobacter , a ubiquitous nitrite oxidizer in natural and anthropized environments, is commonly studied as the model genus performing the second stage of nitrification. In rivers, wastewater treatment plant discharges may affect the nitrite‐oxidizing activity and the responsible genera that are largely associated with sediment. We used a laboratory batch culture approach with Nitrobacter wynogradskyi ssp. agilis strain AG and Nitrobacter hamburgensis strain X 14 to characterize the possible stress effect of wastewater effluent on these populations and to study the possible competition between an effluent strain (X 14 ) and a sediment strain (AG) over a 42‐day incubation time. Immunofluorescence enumerations of each strain showed that they both survived and settled in the sediment, indicating that there was no significant stress effect due to chemical changes caused by the effluent. The development of the strains’ density and activity was directly correlated with the available nitrite concentration. Nevertheless, the potential specific activity was not constant along the so‐called mixotrophic (non‐limiting nitrite concentration) and heterotrophic (nitrite depletion) conditions. This illustrates the inducibility of the nitrite oxidoreductase and indicates the metabolic versatility of the strains. In our experimental conditions, the preferentially autotrophic AG strain appeared more competitive than the preferentially mixo‐ or heterotrophic X 14 strain, including in heterotrophic environment.