Environment anaerobic

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. 

Reductive reactions typically occur in anaerobic environments where there is an abundant supply of electron donors. Electron donors are typically of microbial origin, eg, porphyrins or cysteine, which sometimes leads to confusion regarding the nature, ie, chemical vs enzymatic, of the reductive reaction. By definition, all reductive reactions which are not enzymatically catalyzed are chemical. The most significant chemical reductive reaction is reductive dechlorination. 

Pretreatment For most membrane applications, particularly for RO and NF, pretreatment of the feed is essential. If pretreatment is inadequate, success will be transient. For most applications, pretreatment is location specific. Well water is easier to treat than surface water and that is particularly true for sea wells. A reducing (anaerobic) environment is preferred. If heavy metals are present in the feed even in small amounts, they may catalyze membrane degradation. If surface sources are treated, chlorination followed by thorough dechlorination is required for high-performance membranes [Riley in Baker et al., op. cit., p. 5-29]. It is normal to adjust pH and add antisealants to prevent deposition of carbonates and siillates on the membrane. Iron can be a major problem, and equipment selection to avoid iron contamination is required. Freshly precipitated iron oxide fouls membranes and reqiiires an expensive cleaning procedure to remove. Humic acid is another foulant, and if it is present, conventional flocculation and filtration are normally used to remove it. The same treatment is appropriate for other colloidal materials. Ultrafiltration or microfiltration are excellent pretreatments, but in general they are... 

Sulfate reducers. Active sulfate reducers are found in anaerobic environments. These environments may be highly localized, such as inside a tubercle or beneath a spotty deposit. A thin, fairly regular biofilm is difficult to perceive in such microenvironments. 

Iron and steel aerobic environment anaerobic environment Lead... 

Since the pond is easily accessible and shallow, scientists at ORNL performed several manipulative experiments with caissons to determine the effects of aerobic and anaerobic environments upon the speciation of actinide elements(9). 

Secondary alkanesulfonates are easily biodegradable under aerobic conditions but are less so in an anaerobic environment, a feature common to all sulfonates with the stable carbon-sulfur bond. The recent discussions on anaerobic biodegradation [103] should be put into perspective since in the sewage or deposition path a temporary anaerobic step quickly gives way to a stage where natural conditions, which are aerobic, prevail. Thus, anaerobic biodegradation... 

Fermentation. Many bacteria live in anaerobic environments where they ferment carbohydrates to produce substances such as... 

Hageman, R.H. Flesher, D. (1960). The effect of anaerobic environment on the activity of alcohol dehydrogenase and other enzymes of corn seedlings. Archives of Biochemistry and Biophysics, 87, 203-9. 

The persistence of halogenated phenols and anilines in anaerobic environments is determined by the activity of anaerobic dehalogenating bacteria. Extensive effort has therefore been devoted to isolating the relevant organisms and an increasing number of strains have been obtained in pure culture. They display different specificities for the position of the halogen several bring about dechlorination specifically at positions ortho to the chlorine, while some of them can use the aromatic substrate as... 

Applying a flow equalization tank is usually considered to be an economic approach to meet the peak requirement. However, too long a retention time may result in an anaerobic environment. A decrease in pH and bad odors are common problems during the process. 

Fig. 5.4(a). Structures of iron-sulfur clusters found in proteins, (b) An hydrogenase active site. Note the presence of CO and CN ligands, which could have been present in the primitive anaerobic environment. 

Initially some 15 to 20 elements, that is those available in the original anaerobic environment, gave the general observed features of all cells (see Table 4.11). 

Reactive Black 5 Activated sludge batch reactor Color removal occurred under anaerobic environment, while a slight attenuation was noticed under the aerobic condition [136]... 

In anaerobic environment, the aromatic compounds can mineralize through hydrox-ylation, carboxylation, and redox reactions due to enzymatic reactions. Many of the amines that are formed during the anaerobic decolorization of azo dyes are known... 

In summary, the hydride generation method cannot adequately differentiate between aquated SnIV and Sn11, which may coexist in certain, especially anaerobic, environments found in marine waters. Inorganic tin, speciated as tin (IV) , should probably be regarded as total reducible inorganic tin until more discriminatory techniques become available [578,580]. 

Long-term aim of our project is the construction of a biomolecular device for hydrogen production in combination with light-driven water-splitting as it occurs in the natural process of photosynthesis in plants. Such a semiartificial device should combine the best suited components found in various native systems which - up to now - cannot be found in an individual native system due to incompatibilities and/or different origin (pro- and eukaryotic, meso- and thermophilic, aerobic - anaerobic environment). Advantage of such a system is... 

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