Structure and function of a nitrifying biofilm as determined by microelectrodes and fluorescent oligonucleotide probes

TY - GEN

T1 - Structure and function of a nitrifying biofilm as determined by microelectrodes and fluorescent oligonucleotide probes

AU - Schramm, A.

AU - Larsen, L. H.

AU - Revsbech, N. P.

AU - Amann, R. I.

PY - 1997/10/21

Y1 - 1997/10/21

N2 - Microelectrodes for O2 and NO2-/NO3- and fluorescently labelled 16S rRNA-targeted oligonucleotide probes were combined to examine the activity and stratification of nitrifying bacteria in a trickling filter biofilm. Microprofiles showed that O2 consumption and NO3-/NO2- production were restricted to the upper 50-100 μm of the biofilm. The vertical distribution of the nitrifying bacteria Nitrosomonas sp. and Nitrobacter sp. was investigated by fluorescent in situ hybridisation (FISH) with specific oligonucleotides. Nitrifiers formed a dense layer of cells and cell clusters in the upper part of the biofilm. This correlates well with the measured activity profiles. Ammonia- and nitrite-oxidisers occurred in close vicinity to each other supporting a fast sequential metabolism from ammonia to nitrate. Both species were not restricted to the oxic part of the biofilm, but also appeared - in lower numbers - in the anoxic layers on the bottom of the biofilm. A short term decrease in the O2 concentration of the bulk water resulted in a quick decrease in O2 penetration and metabolic rates inside the biofilm. However, neither the stratification nor the cellular ribosome content of nitrifiers changed within a few hours.

AB - Microelectrodes for O2 and NO2-/NO3- and fluorescently labelled 16S rRNA-targeted oligonucleotide probes were combined to examine the activity and stratification of nitrifying bacteria in a trickling filter biofilm. Microprofiles showed that O2 consumption and NO3-/NO2- production were restricted to the upper 50-100 μm of the biofilm. The vertical distribution of the nitrifying bacteria Nitrosomonas sp. and Nitrobacter sp. was investigated by fluorescent in situ hybridisation (FISH) with specific oligonucleotides. Nitrifiers formed a dense layer of cells and cell clusters in the upper part of the biofilm. This correlates well with the measured activity profiles. Ammonia- and nitrite-oxidisers occurred in close vicinity to each other supporting a fast sequential metabolism from ammonia to nitrate. Both species were not restricted to the oxic part of the biofilm, but also appeared - in lower numbers - in the anoxic layers on the bottom of the biofilm. A short term decrease in the O2 concentration of the bulk water resulted in a quick decrease in O2 penetration and metabolic rates inside the biofilm. However, neither the stratification nor the cellular ribosome content of nitrifiers changed within a few hours.

KW - Biofilm

KW - Biosensor

KW - Image analysis

KW - In situ hybridisation

KW - Microelectrodes

KW - Nitrification

KW - Nitrobacter

KW - Nitrosomonas

UR - http://www.scopus.com/inward/record.url?scp=0030848013&partnerID=8YFLogxK

U2 - 10.1016/S0273-1223(97)00333-8

DO - 10.1016/S0273-1223(97)00333-8

M3 - Conference article

AN - SCOPUS:0030848013

SN - 0273-1223

VL - 36

SP - 263

EP - 270

JO - Water Science and Technology

JF - Water Science and Technology

IS - 1

T2 - Proceedings of the 1996 IAWQ 3rd International Specialised Conference on Biofilm Systems

Y2 - 27 August 1996 through 30 August 1996

ER -