Premium
Microenvironments and distribution of nitrifying bacteria in a membrane‐bound biofilm
Author(s) -
Schramm Andreas,
De Beer Dirk,
Gieseke Armin,
Amann Rudolf
Publication year - 2000
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1046/j.1462-2920.2000.00150.x
Subject(s) - nitrospira , nitrobacter , nitrosomonas europaea , biology , nitrosomonas , biofilm , nitrifying bacteria , exopolymer , microbiology and biotechnology , nitrification , ammonium , nitrite , environmental chemistry , bacteria , nitrate , botany , ecology , chemistry , nitrogen , genetics , organic chemistry
The distribution of nitrifying bacteria of the genera Nitrosomonas, Nitrosospira, Nitrobacter and Nitrospira was investigated in a membrane‐bound biofilm system with opposed supply of oxygen and ammonium. Gradients of oxygen, pH, nitrite and nitrate were determined by means of microsensors while the nitrifying populations along these gradients were identified and quantified using fluorescence in situ hybridization (FISH) in combination with confocal laser scanning microscopy. The oxic part of the biofilm which was subjected to high ammonium and nitrite concentrations was dominated by Nitrosomonas europaea ‐like ammonia oxidizers and by members of the genus Nitrobacter. Cell numbers of Nitrosospira sp. were 1–2 orders of magnitude lower than those of N. europaea . Nitrospira sp. were virtually absent in this part of the biofilm, whereas they were most abundant at the oxic–anoxic interface. In the totally anoxic part of the biofilm, cell numbers of all nitrifiers were relatively low. These observations support the hypothesis that N. europaea and Nitrobacter sp. can out‐compete Nitrosospira and Nitrospira spp. at high substrate and oxygen concentrations. Additionally, they suggest microaerophilic behaviour of yet uncultured Nitrospira sp. as a factor of its environmental competitiveness.