denitrifying bacteria


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denitrifying bacteria:

see nitrogen cyclenitrogen cycle,
the continuous flow of nitrogen through the biosphere by the processes of nitrogen fixation, ammonification (decay), nitrification, and denitrification. Nitrogen is vital to all living matter, both plant and animal; it is an essential constituent of amino acids,
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Denitrifying Bacteria

 

bacteria that reduce nitrates to molecular nitrogen. Denitrifying bacteria include representatives of Pseudomonas, Achromobacter, Bacillus, and Micrococcus. All denitrifying bacteria are aerobes, and they can oxidize organic matter by means of atmospheric oxygen. However, when anaerobic conditions prevail, they use the oxygen of nitrates as an electron acceptor (“respiration by means of nitrates”). Denitrifying bacteria are grown on culture media with nitrates and an indicator that changes color when the nitrates are reduced. The bacteria are widespread in soil and in the water and soil of bodies of water.

denitrifying bacteria

[dē′nī·trə‚fī·iŋ bak′tir·ē·ə]
(microbiology)
Bacteria that reduce nitrates to nitrites or nitrogen gas; most are found in soil.
References in periodicals archive ?
Analysis of nitrite reductases (nirK and nirS) genes and cultivation reveal a depauperate community of denitrifying bacteria in the Black Sea suboxic zone.
"[T]he denitrifying bacteria simply do not get enough organic food to form nitrogen gas, so they are virtually pushed out of the way by anammox bacteria that come with the water from the Equator," explains study coauthor Bo Thamdrup of the University of Southern Denmark.
The inhibitory effects of sulfamethazine and chlortetracycline on nitrate reduction and nitrite production by heterotrophic bacteria in groundwater suggested that the antibiotics have deleterious effects on denitrifying bacteria. Gram-negative bacteria are most likely to be affected by antibiotics.
He wondered, what would happen if denitrifying bacteria could not remove nitrogen as fast as humans were synthesizing it?
Diversity of culturable denitrifying bacteria. Limits of rDNA RFLP analysis and probes for the functional gene, nitrite reductase.
In spite of the higher salinity of mangrove soils, denitrifying bacteria (10.712-22.016 x [10.sup.5]cfu/g soil) and asymbiotic [N.sub.2] fixing bacteria (125.2-213.6 x [10.sup.5]cfu/g soil) were high in all seasons and sites.
Alexander M (1965) Denitrifying bacteria. In 'Methods of soil analysis.
Classic denitrifying bacteria use either oxygen or nitrogen but have a lag (resting) period of some hours to switch between the two.
'Our results indicate that in Antarctic soils, fertilisation stimulates denitrifying bacteria to degrade hydrocarbons in the anoxic portion of the soil profile,' Dr Powell said.
Pumps would control the flow of polluted water into and through the marsh to ensure prolonged contact between nitrate-laden water and denitrifying bacteria. These won't be disease-breeding, bug-infested swamps, but open marshes that host fish and waterfowl, Hey says.
A factor that reduces denitrification efficiency, independently from nitrite, is dissolved oxygen (DO) [10, 11] because most of the common denitrifying bacteria are facultative anaerobes, preferring oxygen to nitrite as the electron acceptor.
Additionally, we examined microbial community properties including microbial biomass, denitrifying bacteria abundance, and rates of denitrification and soil respiration.