Nitrate bacteria

Biological activity of soil microbal flora-nitrate bacteria and azotobacter, which does not occur in virgin soils and weakly cultivated soils or occurs in very fractional amount, intensifies because of it [11]. 

Reversed electron transport reversal of Oxidative phosphorylation (see) in which NAD is reduced by an ATP-dependent reverse transport of electrons. R.e.t. occurs in organisms that oxidize hydrogen donors whose redox potential (see Oxidation) is more positive than that of the pjmdine nucleotide coenzymes, and it operates in the oxidation of substrates not specific for NAD (see Respiratory chain), e.g. Succinate + NAD - Fumate + NADH + H. Tlie redox system succinate/fumarate (E o = -tO - 031V) is 325 mV more positive than the redox system NAJD / NADH + H (E o =-0.32 V) electrons are passed firom succinate to flavoprotein in the respiratory chain, then via NADH-dehydrogenase to NAD. R.e.t. has been shown in nitrate bacteria (Nitrobac-ter), insect flight muscle mitochondria and kidney mi-... 

Fig. 7. A bead filter, one of many types of biological filters, shown in association with a laboratory-scale recirculating water system. Small plastic beads inside the fiber glass chamber provide surface area for colonisation by bacteria that convert ammonia to nitrate.

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). 

Molybdenum. Molybdenum is a component of the metaHoen2ymes xanthine oxidase, aldehyde oxidase, and sulfite oxidase in mammals (130). Two other molybdenum metaHoen2ymes present in nitrifying bacteria have been characteri2ed nitrogenase and nitrate reductase (131). The molybdenum in the oxidases, is involved in redox reactions. The heme iron in sulfite oxidase also is involved in electron transfer (132). 

Soil Nutrient. Molybdenum has been widely used to increase crop productivity in many soils woddwide (see Fertilizers). It is the heaviest element needed for plant productivity and stimulates both nitrogen fixation and nitrate reduction (51,52). The effects are particularly significant in leguminous crops, where symbiotic bacteria responsible for nitrogen fixation provide the principal nitrogen input to the plant. Molybdenum deficiency is usually more prominent in acidic soils, where Mo(VI) is less soluble and more easily reduced to insoluble, and hence unavailable, forms. Above pH 7, the soluble anionic, and hence available, molybdate ion is the principal species. 

Reduction of Nitro Substituents. These reactions are very common in anaerobic environments and result in amine-substituted pesticides anaerobic bacteria capable of reducing nitrate to ammonia appear to be primarily responsible. All nitro-substituted pesticides appear to be susceptible to this transformation, eg, methyl parathion (7) (eq. 9), triduralin, and pendimethalin. 

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. 

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. 

A large proportion (30-90% in tropical waters) is absorbed by bacteria and oxidized to FfjS in order to allow the sulfur to be used by these organisms. Once in the atmosphere, DMS is oxidized by various free radicals such as hydroxyl and nitrate ions. In the presence of low concentrations of NO the hydroxyl reaction... 

The main agents of these losses are the microbes and small animals, such as springtails and mites, that inhabit the soil. These feed on organic matter that contains carbon and nitrogen and produce carbon dioxide and ammonium ions as waste products. Other bacteria convert the ammonium to nitrate. Like most of us, these organisms are most active when the conditions suit them best, and their preferred options are warmth and moisture. In early autumn, the soil is still warm... 

Nitrifying bacteria Bacteria that change the ammonia and organic nitrogen in wastewater into oxidized nitrogen (usually nitrate). 

Obligate aerobe Bacteria which require the presense of oxygen, such as Pseudomonas flourescens. A few strains of this species are capable of utilizing nitrate to allow anaerobic respiration. 

Anaerobic reactor A bioreactor in which no dissolved oxygen or nitrate is present and microbial activity is due to anaerobic 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. 

This enzyme is of wide occurrence in bacteria where it is concerned with the reduction of nitrate and CO2 as well as sulphur. Methods for its estimation depend on measuring some activity of hydrogenase by (a) dye reduction (benzyl viologen or methylene blue), (b) isotopic exchange and (c) evolution of molecular hydrogen. Interpretation of quantitative results is difficult due to the complex relationship between the enzyme cell structure and the particular method selected. ... 

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