Nitrite bacteria

Most faucet units and pitchers use carbon filters that absorb lead, chlorine by-products, and some organic chemicals, as well as odors and tastes. They won t remove heavy metals, pesticides, nitrites, bacteria, or microbes, but they are the least-expensive filter type and are sufficient for most needs. 

Sodium Nitrate and Sodium Nitrite. Nitrates and nitrites ate used in meat-curing processes to prevent the growth of bacteria that cause botulism. Nitrates have been shown to form low, but possibly toxic, levels of nitrosamines in certain cured meats. For this reason, the safety of these products has been questioned, and use is limited (80). 

Bismuth subnitrate [1304-85-4] (basic bismuth nitrate) can be prepared by the partial hydrolysis of the normal nitrate with boiling water. It has been used as an antacid and in combination with iodoform as a wound dressing (183). Taken internally, the subnitrate may cause fatal nitrite poisoning because of the reduction of the nitrate ion by intestinal bacteria. 

When organics containing reduced nitrogen are degraded, they usually produce ammonium, which is in equilibrium with ammonia. As the pK for NH3 NH4" is 9.3, the ammonium ion is the primary form present in virtually all biological treatment systems, as they operate at pH < 8.5 and usually in the pH range of 6.5-7.5. In aerobic reactions, ammonium is oxidized by nitrifying bacteria (nitrosomonas) to nitrite... 

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. 

In 1973, the first naturally occurring isobacteriochlorin, iron-containing siroheme, was isolated1 from a sulfite reductase of Escherichia coli. Later it was also discovered in sulfite and nitrite reductases of numerous bacteria and plants.2 Iron-free sirohydrochlorins (also called factor II) were discovered in vitamin B12 producing bacteria.3-4 Together with factor III. a sirohydrochlorin methylated in the 20-position, the reduced forms of factor II and factor III were identified as biosynthetic intermediates in the biosynthesis of vitamin B12.5... 

Heme d,6 another isobacteriochlorin, occurs as one of two cofactors in the reductase cytochrome cdj which mediates the nitrite reduction to nitrogen monoxide (NO) and from there to dinitrogen oxide (N20) in denitrifying bacteria.7... 

Sodium nitrite is produced in the human body by the action of saliva on sodium nitrate, and is important in controlling bacteria in the stomach, to prevent gastroenteritis. The body produces more sodium nitrite than is consumed in food. 

Sodium nitrate has been used for centuries to cure meat. Bacterial action during curing converts the sodium nitrate into sodium nitrite, which kills the bacteria that cause botulism, and combines with the myoglobin in the meat to form the pink color associated with ham. 

Bacteria have been Implicated in the formation of N-nitroso compounds under a wide variety of conditions representing both vitro and vivo situations Mechanisms of participation and/or catalysis Include a) decrease of the pH of the system, b) reduction of nitrate to nitrite, c) adsorption of amine onto the cell surface or cytoplasmic membrane, d) actual enzymatic formation. The literature of the field will be reviewed and experimental evidence which tests the above mechanisms will be presented ... 

It seemed possible that a catalytic effect of the bacteria upon nitrosation might be masked by the high level - 0 2% - of nitrite used in these experiments, so we repeated the work with lower concentrations of nitrite (Table I) The catalysis by the medium alone is considerably greater at these limiting concentrations of nitrite, and again the bacteria do not further enhance the rate of nitrosation. 

We conclude that the major role of bacteria in the nitrosa-tion of dimethylamine is the reduction of nitrate to nitrite and the lowering of the pH of the medium. Furthermore, the complex medium Itself catalyzes nitrosation. The nature of this catalysis is not known, although it could be due to the presence of carbonyl compounds, cysteine, or a variety of other compounds which are known to catalyze nitrosation (17). 

Nitrite is a weak reducing agent and is oxidized to nitrate by strong chemical oxidants or by nitrifying bacteria. It also oxidizes reduced substances. 

The nitrite results from reduction of nitrate by bacteria abnormally present in the gastric mucosa and the gastric cavity. The bacteria grow situ because the pH is elevated as a result of loss of HCl secretion secondary to the loss of parietal cells and their replacement by intestinal-type epithelium. Parietal cells are lost as a result of chronic atrophic gastritis. What... 

Nitrite (or compounds at the same or lower oxidation level) is produced microbiologically from nitrate, and may then react with the substrate to produce stable end products. The production of nitrite is the sole metabolic function of the bacteria and, in view of concern over the presence of nitrate in groundwater, the following possible environmental significance of these or analogous reactions should not be overlooked ... 

Anaerobic lithotrophs that oxidize ammonium using nitrite as electron acceptor (anammox) are noted later in the section on anaerobic bacteria. 

Although they have not been obtained in pure culture, chemolithotrophic anaerobic bacteria (anammox) that oxidize ammonia using nitrite as electron donor and CO2 as a source of carbon have been described. In addition, they can oxidize propionate to CO2 (Giiven et al. 2005) by a pathway that has not yet been resolved. 

An important development is the appreciation of the role of anammox bacteria. These carry out the anaerobic reaction between NH4 and NO2 in which nitrite is the electron donor with the production of N2 (Schmid et al. 2005). Several groups of bacteria have been implicated, and all of them belong to the phylum Planctomyces, although quite distinct organisms may be involved. They... 

J. T. Sears, R. Muller, and M. A. Reinsel. Inhibition of sulfate-reducing bacteria via nitrite production. Patent WO 9612867, 1996. 

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