Nitrification nitrifying bacteria

Salpeter-ather, m. nitric ether (ethyl nitrate), -bakterien, n.pl. nitrifying bacteria, -bil-dung, /. nitrification, -blumen, f.pl. niter efflorescence, -damp/, -dupst, m. nitrous fumes, -erde, /. nitrous earth, -erzeugung, /. niter production nitrification. 

Lodhi, M.A.K. and Killingbeck, K.T. (1980). Allelopathic inhibition of nitrification and nitrifying bacteria in a ponderosa pine (Pinus ponderosa Dough) community. American Journal of Botany 67 1423-1429. 

Nitrification The microbial oxidation of ammonium to nitrite and then to nitrate by Oj. In the ocean, this process is mediated by nitrifying bacteria. 

Allelopathic effects of juglone on nitrifying bacteria. I am unaware of any reports dealing specifically with juglone as an inhibitor of nitrification, but there have been several reports of inhibition of nitrification in grassland and a few reports Indicating inhibition in forest soil. The causal agents in both situations have been... 

Konig et al. [80-84] demonstrated that microbial sensors are suitable for the summary quantification of nitrifiable compounds (see also Sect. 3.3.1) as well as for the detection of nitrification inhibiting effects. Such biosensors, which contain a mixed population of the nitrifying bacteria Nitrosomonas sp. and Nitrobacter sp., exhibit a specific supplementary metabolic capacity. This enables the amperometric determination of ammonia according the following scheme of nitrification ... 

Henriksen, K., Hansen, J.I., and Blackburn, T.H. (1981) Rates of nitrification, distribution of nitrifying bacteria, and nitrate fluxes in different types of sediment from Danish waters. Mar. Biol. 61, 299-304. 

The rate of bacterial growth and hence the rate of nitrification is both temperature and pH dependent. Maximum bacterial activity occurs at about 28°C and a pH of about 8, Below a temperature of about 2°C, the reaction is very slow (Fig. 8.7). Below pH 5.5, the nitrifying bacteria decrease their activity, and below pH 4.5 the nitrification process is severely restricted lack of oxygen also inhibits nitrification. As noted above, oxidation of NH to NO is an enzyme-driven reaction and commonly the Km (see Chapter 7) under optimum conditions is observed to be somewhere around 2.5 mM. Some Km values below 2.5 mM are observed under high pH values when a large fraction of the ammonium is in the NH3 form. 

Nitrification seems limited to a number of autotrophic bacteria. The dominant genus that is capable of oxidizing ammonia to nitrite in soils is Nitmsomonas, and the dominant genus capable of oxidizing nitrite to nitrate is Nitrobacter. Normally, the two processes are closely connected and nitrite accumulation does not occur. Nitrifying bacteria are chemolithotrophs that utilize the energy derived from nitrification to assimilate C02. 

In cultures of nitrifying bacteria, the dependence of nitrification rate on substrate concentration is first order at low concentrations (10—100 pM these... 

Nitrifying bacteria are traditionally considered to be obligate aerobes they require molecular oxygen for reactions in the N oxidation pathways and for respiration. They are reputed to be microaerophiles, however, who thrive best under relatively low oxygen conditions. Microaerophily may be important in interface environments such as the sediment water interface and in the oxygen minimum zones of the ocean. The role of oxygen in sedimentary nitrification and coupled nitrification/ denitrification is discussed above in the section on nitrification in sediments. 

As an alternative to partial assimilatory NOs reduction by phytoplankton, oxidation of NH4+ by Bacteria and Archaea (the first step in the 2-step process of nitrification) can produce N02 as an intermediate product. Nitrifying bacteria were first isolated from the marine environment by Watson (1965) and are now known to be ubiquitous in the global ocean. Wada and Hattori (1971) used a sensitive chemical assay to measure changes in N02 in incubated samples, to conclude that NH4+ was the major source of N02 in the PNM in the central North Pacific Ocean. Miyazaki et al. (1973, 1975), using a N tracer method, found that, in Sagami Bay and in the western North Pacific, NH4+ and NOs were both important sources ofN02. ... 

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