Proteins natural organic matter

Natural organic matter in aquatic media are complex mixture of substances such as polysaccharides, proteins, peptides, lipids, and humic substances (Duursmu and Dawson, 1981 Buffie, 1984). Humic material is itself a mixture of polymers of a wide range of molecular weights (Buffle, 1988). Besides naturally occurring substances, various artificial compounds are introduced in natural water as the result of human activities. 

The modified membrane surfaces exhibit more hydrophilic and negative charged features after the treatment. Grafting with MA and AAG decreases the permeability of natural organic matter (NOM) to less than half of the untreated membrane. The modification reduces fouling by foulants such as NOM. In a similar study, best results, with respect to protein retention and protein solution flux, were obtained by grafting NVP, 2-acrylam-ido-2-methyl-l-propane sulfonic acid, and AA onto a 50 kDalton PES. ... 

Throughout the literature there appear numerous findings of NOM fluorescence values reported in volts or relative fluorescence. Although the scientific community gains from these reports, the relative spatial and temporal trends in fluorescence values, it is impossible to compare absolute intensities without calibration to a known standard. Calibration of field sensor fluorescence intensity is routinely conducted using three standards. QS and natural organic matter (NOM) samples are utilized for humic- and fulvic-like fluorescence calibration, where NOM can be either humic acid standards or filtered sample water. The third standard is tryptophan, which is used for calibration of protein fluorescence. 

Cellulose is the most abundant of naturally occurring organic compounds for, as the chief constituent of the eell walls of higher plants, it comprises at least one-third of the vegetable matter of the world. The cellulose eontent of such vegetable matter varies from plant to plant. For example, oven-dried cotton contains about 90% cellulose, while an average wood has about 50%. The balance is composed of lignin, polysaccharides other than cellulose and minor amounts of resins, proteins and mineral matter. In spite of its wide distribution in nature, cellulose for chemical purposes is derived commerically from only two sources, cotton linters and wood pulp. 

Low-volatility natural organic material such as polysaccharides and higher molecular weight proteins sometimes produced low results. In the Hannaker and Buchanan method [82] these problems are overcome by using a solution-phase oxidant and enclosing the system in a sealed tube. In this way all of the constituents are fully contained and exposed to oxidation and, moreover, oxidation of the organic matter to carbon dioxide is complete for the greater majority of compounds. 

A number of invertebrates deposit phosphate in their shell structures24. In the articulate brachiopod shell — Lingula — apatite crystallites occur up to about 1000 A long. Little is known, however, on the nature of shell organic matter, except that the amount of chitinous material exceeds that of protein fraction by a factor of two408. ... 

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