Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers. [Pseudomonas fluorescens; Serratia marcescens; Alcaligenes faecalis]
The authors investigated the effect of the partial pressure of oxygen (pO/sub 2/) on the production of NO and N/sub 2/O by a wide variety of common soil nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The production of NO per cell was highest by autotrophic nitrifiers and was independent of pO/sub 2/ in the range tested (0.5 to 10%), whereas N/sub 2/O production was inversely proportional to pO/sub 2/. Nitrous oxide production was highest in the denitrifier Pseudomonas fluorescens, but only under anaerobic conditions. The molar ratio of NO/N/sub 2/O produced was usually greater than unity for nitrifiers and much less than unity for denitrifiers. Chemodenitrification was the major source of both the NO and N/sub 2/O produced by the nitrate respirer Serratia marcescens. Chemodenitrification was also a possible source of NO and N/sub 2/O produced by the nitrate respirer Serratia marcescens. Chemodenitrification was also a possible source of No and N/sub 2/O in nitrifier cultures but only when high concentrations of nitrite had accumulated or were added to the medium. Although most of the denitrifiers produced NO and N/sub 2/O only under anaerobic conditions, chemostat cultures of Alcaligenes faecalis continued to emit these gases even when the cultures were sprayed with air. Based upon these results, we predict that aerobic soils are primary sources of NO and that N/sub 2/O is produced only when there is sufficient soil moisture to provide the anaerobic microsites necessary for denitrification by either denitrifiers or nitrifiers.
- Research Organization:
- National Aeronautics and Space Administration, Hampton, VA
- OSTI ID:
- 5014275
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 51:5; ISSN AEMID
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
550700* -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
AEROBIC CONDITIONS
AIR POLLUTION
ANAEROBIC CONDITIONS
BACTERIA
BIOSYNTHESIS
CHALCOGENIDES
CHEMICAL REACTIONS
DENITRIFICATION
METABOLISM
MICROORGANISMS
NITRIC OXIDE
NITRIFICATION
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
OXIDES
OXYGEN COMPOUNDS
POLLUTION
POLLUTION SOURCES
PSEUDOMONAS
RESPIRATION
SOILS
SYNTHESIS