Polysaccharide naturally occuring

It is clear that green polymers, as defined by their biodegradability, are almost exclusively biopolymers. The major classes of biopolymer of interest here are proteins and polysaccharides, naturally occurring biopolymers, and these are subdivided into various sub-classes, with different applications, as described above. Other polymers of interest are the bacterial polyesters and polylactides. All of these polymers have the potential to be processed into new materials, but clearly not all of these will have either attractive properties or be economically viable materials. 

Other polymers, such as poly methacrylates, have been studied, as well as esters of naturally occurring polysaccharides. References can be found in the literature cited in the list of further reading. 

L (+) Arabmose is a naturally occurring L sugar It is obtained bj acid hydrolysis of the polysaccharide present in mesquite gum Write a Fischer pro ection for L (+) arabmose... 

Biopolymers are the naturally occurring macromolecular materials that are the components of all living systems. There are three principal categories of biopolymers, each of which is the topic of a separate article in the Eniyclopedia proteins (qv) nucleic acids (qv) and polysaccharides (see Carbohydrates Microbial polysaccharides). Biopolymers are formed through condensation of monomeric units ie, the corresponding monomers are amino acids (qv), nucleotides, and monosaccharides, for proteins, nucleic acids, and polysaccharides, respectively. The term biopolymers is also used to describe synthetic polymers prepared from the same or similar monomer units as are the natural molecules. 

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. 

Biopolymers Naturally occurring macromolecules that include proteins, nucleic acids, and polysaccharides. 

By far the majority of carbohydrate material in nature occurs in the form of polysaccharides. By our definition, polysaccharides include not only those substances composed only of glycosidically linked sugar residues but also molecules that contain polymeric saccharide structures linked via covalent bonds to amino acids, peptides, proteins, lipids, and other structures. 

Data from f.a.b.-m.s., and also f.d.-m.s., revealed the existence of naturally occurring, large cyclic polysaccharides. The first indication that a molecule may be cyclic comes from its precise molecular-weight determination. Cyclic molecules are 18 mass units less than their linear counterparts. Loss of water may, of course, occur in a number of ways, for example, by dehydration or lactonization, and conclusive evidence for the presence of a cyclic molecule can only be obtained from f.a.b.-m.s. of suitable derivatives, such as the permethyl derivative. Cyclic and dehydrated linear polymers are distinguishable after permethylation, as the cyclic polymer will incorporate one methyl group less than the linear molecule. 

Naturally occurring polysaccharides and their derivatives form the predominant group of water-soluble species generally used as thickeners to impart viscosity to treating fluids [1092]. Other synthetic polymers and biopolymers have found ancillary applications. Polymers increase the viscosity of the fi ac-turing fluid in comparatively small amounts. The increase in fluid viscosity of hydraulic fracturing fluids serves for improved proppant placement and fluid loss control. Table 17 summarizes polymers suitable for fracturing fluids. 

Polymers are examples of organic compounds. However, the main difference between polymers and other organic compounds is the size of the polymer molecules. The molecular mass of most organic compounds is only a few hundred atomic mass units (for reference, atomic hydrogen has a mass of one atomic mass unit). The molecular masses of polymeric molecules range from thousands to millions of atomic mass units. Synthetic polymers include plastics and synthetic fibers, such as nylon and polyesters. Naturally occurring polymers include proteins, nucleic acids, polysaccharides, and rubber. The large size of a polymer molecule is attained by the repeated attachment of smaller molecules called monomers. 

Starch is the major energy storage polysaccharide of cereal crops. It is a natural polymer of dextrose. Starch has two naturally occurring... 

Both synthetic and naturally occurring polymers have been used as CSPs. Figure 3.2 shows typical CSPs prepared from optically active polymers (1-18) 1-15 are totally synthetic polymers, including vinyl polymers (1-7), polyamides (8-12), polyurethanes (13), polyacetylene (14), and polysaccharide analogue (15). The CSPs 16-18 are based on natural polymers, proteins (16), and polysaccharides (17, 18). 

The biological availability of contaminating and naturally occurring organic compounds can be estimated by finding their solubility in water. The more soluble the compound, the more available it is for decomposition. While this is true for most organic compounds, there are some that are soluble but also recalcitrant to decomposition. This is the result of complex, sometimes multi-cyclic, structures that inhibit decomposition, such as those of polysaccharides and lignins [2],... 

Naturally occurring cellulose is a polydisperse linear homogeneous polysaccharide based on 1,4-D-glucopyranose repeat units, with an... 

Naturally occurring compounds in sediments (lipids, polysaccharides, lignins, etc.) have also been determined by this method. The compounds generated from non-polluted sediments are completely different and easily discriminated from anthropogenic contributions. 

The phosphate esters and, to lesser extent, the sulphate esters of monosaccharides are very important naturally occurring derivatives. Metabolism of carbohydrates involves the formation and interconversion of a succession of monosaccharides and their phosphate esters of which glucose-1-phosphate and fruc-tose-6-phosphate are important examples. The sulphate esters of monosaccharides or their derivatives (usually esterified at carbon 6) are found in several polysaccharides, notably chondroitin sulphate, which is a constituent of connective tissues. 

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