Nitrification at low pH by aggregated chemolithotrophic bacteria

Journal Article · Sun Dec 01 04:00:00 EST 1991 · Applied and Environmental Microbiology; (United States)

OSTI ID:5968738

De Boer, W; Klein Gunnewiek, P J.A.; Laanbroek, H J ^[1]; Veenhuis, M ^[2]; Bock, E ^[3]

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1. Inst. for Ecological Research, Haren (Netherlands)
2. Univ. of Groningen, Haren (Netherlands)
3. Inst. fuer Allgemeine Botanik der Univ. Hamburg (West Germany)

A study was performed to gain insight into the mechanism of acid-tolerant, chemolithotrophic nitrification. Microorganisms that nitrified at pH 4 were enriched from two Dutch acid soils. Nitrate production in the enrichment cultures was indicated to be of a chemolithoautotrophic nature as it was (1) completely inhibited by acetylene at a concentration as low as 1 {mu}mol/liter and (2) strongly retarded under conditions of carbon dioxide limitation. Electron microscopy of the enrichment cultures showed the presence of bacteria that were morphologically similar to strains of known chemolithotrophic nitrifying genera. Many of the enriched bacteria, in particular those that were identified as ammonium oxidizers, were aggregated. Filtration experiments indicated that aggregated cells were able to nitrify at low pH, whereas single cells were not. It is hypothesized that cells inside the aggregates are protected against the toxicity of nitrous acid. Nitrification by aggregated chemolithoautotrophic bacteria may be the dominating process of nitrate formation in many acid soils as it does not appear to depend on the existence of microsites of high pH (acid-sensitive autotrophic nitrification) or on the availability or organic carbon (heterotrophic nitrification).

• OSTI ID: 5968738
• Journal Information: Applied and Environmental Microbiology; (United States), Journal Name: Applied and Environmental Microbiology; (United States) Vol. 57:12; ISSN 0099-2240; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
AGGLOMERATION
AMMONIUM COMPOUNDS
BACTERIA
CHEMICAL REACTIONS
ELECTRON MICROSCOPY
GROWTH
MICROORGANISMS
MICROSCOPY
MORPHOLOGY
NITRIFICATION
OXIDATION
PH VALUE
SOILS