Nitrobacter bacteria

Aerobic, chemolithotrophic bacteria. Colorless sulfur bacteria Thiobacillus iron or manganese-oxidizing bacteria, magnetotactic bacteria nitrifying bacteria Nitrobacter, Nitrosomonas... 

In some cases, the effects of complex environmental mixtures could be accounted for in terms of concentration-additive effects of a few chemicals. In sediments of the German river Spittelwasser, which were contaminated by chemical industries in its vicinity, around 10 chemicals of a cocktail of several hundred compounds were found to explain the toxicity of the complex mixture to different aquatic organisms (Brack et al. 1999). The complex mixture of chemicals contained in motorway runoff proved toxic to a crustacean species (Gammarus pulex). Boxall and Maltby (1997) identified 3 polycyclic aromatic hydrocarbons (PAHs) as the cause of this toxicity. Subsequent laboratory experiments with reconstituted mixtures revealed that the toxicity of motorway runoff could indeed be traced to the combined concentration-additive effects of the 3 PAHs. Svenson et al. (2000) identified 4 fatty acids and 2 monoterpenes to be responsible for the inhibitory effects on the nitrification activity of the bacteria Nitrobacter in wastewater from a plant for drying wood-derived fuel. The toxicity of the synthetic mixture composed of 6 dominant toxicants agreed well with the toxicity of the original sample. 

The second step, nitrite (NO ) to nitrate (N03), is carried out by a different bacteria— nitrobacter ... 

The nitrite ion (NOJ) in soil is oxidized to nitrate ion (NO3 ) by the bacteria Nitrobacter agilis in the presence of oxygen. The half-reduction reactions are... 

Nitrobacter, an aerobic bacterium, can materially depress pH by oxidizing nitrite (NO2 ) to nitrate (NOa ), in effect producing nitric acid. Acidity may increase until pH is between 3 and 5. Such bacteria require high concentrations of oxygen and cause problems only in oxygenated systems. 

To gain more understanding of the European alder decline and because of our concern about the future growth of black walnut planted with nitrogen-fixing species, a study was initiated to measure soil juglone concentration and to estimate the number of Nitrobacter and Nltrosomonas bacteria in a black walnut plantation containing plots of black walnut alone and in mixture with European alder and autumn-olive. 

Although the number of Nitrosomonas bacteria was greater than the number of Nitrobacter in each treatment plots, only Nitrobacter differed significantly among treatments (Table II). Both Nitrosomonas and Nitrobacter counts decreased significantly with sampled depths. 

One of the pitfalls of microbial sensors, viz. their low selectivity, can be overcome by combining cells with an immobilized enzyme. Thus, creatinine deaminase (CDA, EC 3.5.4.21) hydrolyses creatinine to N-methylhydantoin and ammonium ion, the ammonia produced being successively oxidized to nitrite and nitrate ion by nitrifying bacteria. These bacteria have not yet been characterized but are known to be a mixed culture of Nitrosomonas sp. and Nitrobacter sp. The reaction sequence involved is as follows ... 

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 ... 

As bacteria die, ammonia is typically produced as a product of decomposition. Aerobic nitrifying bacteria such as Nitrosomonas and Nitrobacter can oxidize ammonia (NH3) to nitrate (N03 ). As a result of this process, the pH of the system can be reduced. 

As is indicated in Fig. 24-1, the interconversions of nitrate and nitrite with ammonia and with organic nitrogen compounds are active biological processes. Two genera of nitrifying soil bacteria, which are discussed in Chapter 18, oxidize ammonium ions to nitrate. Nitrosomas carries out the six-electron oxidation to nitrite (Eq. 18-17) and Nitrobacter the two-electron oxidation of nitrite to nitrate (Eq. 18-18).79... 

Branched-chain monosaccharides have now been detected as components of bacterial polysaccharides. The known examples include yersiniose [3,6-dideoxy-4-C-(hydroxyethyl)-D-xy/o-hexose228] from Y. pseudotuberculosis, a 3-C-(hydroxymethyl)pentofuranose from Coxiella bumetti,229 and 6-deoxy-3-C-methylhexoses from the same organism and from Nitrobacter hamburgiensis.229 Several branched-chain monosaccharides were identified as components of antibiotics, and the pathways of their biosynthesis in bacteria were studied. These investigations were discussed in detail by Grisebach in this Series.230 The usual precursors for the formation of the monosaccharides of this group are the nucleoside 6-deoxyhexosyl-4-ulose diphosphates 7a and 7b. 

The oxidation of ammonia to nitrite, in the process of nitrification, is brought about mainly by autotrophic bacteria such as Nitrosomonas species. The oxidation of nitrite to nitrate is due to the action of Nitrobacter species. 

Biocorrosion in well-oxygenated cooling systems can also involve other types of bacteria, such as nitrifying bacteria, which are commonly found where ammonia is present (say from refinery or fertilizer plant leaks). They are principally aerobic and oxidize ammonia to nitrate, causing serious local falls in pH that result in nitric acid corrosion. Examples are Nitrosomonas sp. and Nitrobacter sp. 

Nitrogen converters Nitrobacter, Nitrosomonas, and Nitrococcus sp. are nitrifying bacteria that convert ammonia and nitrite to nitrate, causing corrosion and damage to concrete. 

The other genus (i.e., Nitrobacter sp.) of bacteria oxidizes nitrite to nitrate as follows ... 

Attack by organisms other than SRB. Ammonia and amines are produced by microbial decomposition of organic matter under both aerobic and anaerobic conditions (ammo-nification). (Stott)5 These compounds are oxidized to nitrite by aerobic bacteria such as Nitrosomonas or Nitrobacter species. Nitrobacter is very efficient at destroying the corrosion-inhibition properties, of nitrate-based corrosion inhibitors by oxidation, unless a biocidal agent is included in the formulation. The release of ammonia at the surfaces of heat-exchanger tubes has a detrimental effect. (Stott)5... 

Based on Reactions 8.14 and 8.15, nitrification is energetically favorable (overall AG° = -84 kcal). The intermediate nitrogen form, NO , rarely accumulates in significant concentrations because nictrobacter normally acts as fast or faster than the N02-producing bacteria. However, nitrobacter is more sensitive to ammonia than nitrosomonas, and for this reason nitrite may accumulate under high concentrations of NH (Fig. 8.5) but not under low concentrations of NH4 (Fig. 8.6)... 

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. 

The reactions in the nitrification process are mediated by two types of autotrophic bacteria Nitrosomonas and Nitrobacter. The ammonia comes from the nitrogen content of any organic substance, such as proteins, that contains about 16% nitrogen. As soon as the ammonia has been hydrolyzed from the organic substance, Nitrosomonas consumes it and in the process also consumes oxygen according to... 

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