This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tarre, S.
Right arrow Articles by Green, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tarre, S.
Right arrow Articles by Green, M.
Agricola
Right arrow Articles by Tarre, S.
Right arrow Articles by Green, M.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, November 2004, p. 6481-6487, Vol. 70, No. 11
0099-2240/04/$08.00+0     DOI: 10.1128/AEM.70.11.6481-6487.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

High-Rate Nitrification at Low pH in Suspended- and Attached-Biomass Reactors

Sheldon Tarre and Michal Green*

Faculty of Civil and Environmental Engineering, Technion, Haifa, Israel

Received 11 May 2004/ Accepted 4 July 2004

This article reports on high-rate nitrification at low pH in biofilm and suspended-biomass reactors by known chemolithotrophic bacteria. In the biofilm reactor, at low pH (4.3 ± 0.1) and low bulk ammonium concentrations (9.3 ± 3.3 mg · liter–1), a very high nitrification rate of 5.6 g of N oxidized · liter–1 · day–1 was achieved. The specific nitrification rate (0.55 g of N · g of biomass–1 · day–1) was similar to values reported for nitrifying reactors at optimal pH. In the suspended-biomass reactor, the average pH was significantly lower than that in the biofilm reactor (pH 3.8 ± 0.3), and values as low as pH 3.2 were found. In addition, measurements in the suspended-biomass reactor, using isotope-labeled ammonium (15N), showed that in spite of the very low pH, biomass growth occurred with a yield of 0.1 g of biomass · g of N oxidized–1. Fluorescence in situ hybridization using existing rRNA-targeted oligonucleotide probes showed that the nitrifying bacteria were from the monophyletic genus Nitrosomonas, suggesting that autotrophic nitrification at low pH is more widespread than previously thought. The results presented in this paper clearly show that autotrophic nitrifying bacteria have the ability to nitrify at a high rate at low pH and in the presence of only a negligible free ammonia concentration, suggesting the presence of an efficient ammonium uptake system and the means to cope with low pH.

* Corresponding author. Mailing address: Faculty of Civil and Environmental Engineering, Technion, Haifa 32000, Israel. Phone: 972-4-829-3479. Fax: 972-4-829-5696. E-mail: agmgreen{at}tx.technion.ac.il.

Applied and Environmental Microbiology, November 2004, p. 6481-6487, Vol. 70, No. 11
0099-2240/04/$08.00+0     DOI: 10.1128/AEM.70.11.6481-6487.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Gieseke, A., Tarre, S., Green, M., de Beer, D. (2006). Nitrification in a Biofilm at Low pH Values: Role of In Situ Microenvironments and Acid Tolerance.. Appl. Environ. Microbiol. 72: 4283-4292 [Abstract] [Full Text]  
  • Freitag, T. E., Chang, L., Clegg, C. D., Prosser, J. I. (2005). Influence of Inorganic Nitrogen Management Regime on the Diversity of Nitrite-Oxidizing Bacteria in Agricultural Grassland Soils. Appl. Environ. Microbiol. 71: 8323-8334 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»