Carbohydrates applied

Harris, J.F. "Acid Hydrolysis and Dehydration Reactions for Utilizing Plant Carbohydrates," Applied Polymer Symposium. 1975, 28, 131-144. 

Huford JR (1980) Surface-active agents derived from disaccharides. In Lee CK (ed) Developments in food carbohydrates. Applied Science, England... 

To understand the chemistry of these more complex carbohydrates, we must first learn the principles of carbohydrate structure and reactions, using the simplest monosaccharides as examples. Then we will apply these principles to more complex disaccharides and polysaccharides. The chemistry of carbohydrates applies the chemistry of alcohols, aldehydes, and ketones to these polyfunctional compounds. In general, the chemistry of biomolecules can be predicted by applying the chemistry of simple organic molecules with similar functional groups. 

A) Molisch Test for Carbohydrates. Apply the test to small amounts of the following sucrose, starch, and paper fibers. Place in a test tube 2 ml of one per cent carbohydrate solution or dispersion. Add 2 drops of a 10 per cent solution of a-naphthol in alcohol, and mix. Add this carefully down the side of a tube containing 2 ml of concentrated sulfuric acid so that it will form a separate layer. Carbohydrates give a purple color at the junction of the two liquids. 

Treatment of the galactofuranosyl-containing pol3nner(s) with alkali resulted in a decrease of 11 seryl and 9 threonyl residues, based on a polypeptide of 110 amino acyl residues. Mannobiose was the major low molecular weight oligosaccharide released by alkali (not shown). However, only 49% of the carbohydrate applied to the column was eluted. 

By far the best known complex carbohydrates of prokaryotic cells are those of the bacteria and their biosynthesis is perhaps better understood than that of any other group of glycoconjugates. Much of what is known of bacterial carbohydrates applies equally to those of related groups such as blue-green algae and the actinomycetes and their apparent diversity resolves to a relatively few biosynthetic mechanisms, which are in many ways simpler than those of the eukaryotes. This chapter will deal with little other than the carbohydrates of true bacteria, though it should be remembered that there are other prokaryotes and that some of these may well prove to have very different systems of saccharide synthesis. 

Tarelli, E. et al, Dev. Food Carbohydr., Applied Science Publ., 1980, 187 Khan, R. et al, Adv. Carbohydr. Chem. 

Birch, G.G., Green, L.F. (Eds.) Molecular structure and function of food carbohydrates. Applied Science Publ. London. 1973... 

Allen, R. M. and H. R Bennetto. Microbial fuel cells Electricity production from carbohydrates. Applied Biochemistry and Biotechnology 39-40 27-40,1993. 

The use of carbohydrates as SM s has greatly expanded in recent years, and many cases have been summarized in a text by Hanessian.33 Several examples of such syntheses are indicated in Chart 15. Other commercially available chiral molecules such as a-amino acids or a-hydroxy acids have also been applied widely to the synthesis of chiral targets as illustrated by the last two cases in Chart 15. 

Some six hundred structures of naturally occurring carbogenic molecules appe on the pages which follow, together with the name of each compound and references to the original literature of successful chemical synthesis. Thus, Part Three of this book is effectively a key to the literature of chemical synthesis as applied to the complex molecules of nature. The survey does not include oligomeric or polymeric structures, such as peptides, proteins, carbohydrates and polynucleotides, which fall outside the scope of this book because they can be assembled by repetitive procedures. 

Preswelled Sephacryl S-1000 was prepared in a K26/100 column (88 X 2.6 cm). Equilibration with 0.005 M NaOH containing 0.002% NaN3 at a flow rate of 0.67 ml/min was achieved after 20 hr. Sample solutions were applied with a 5-ml injection loop. The mass and iodine-complexing potential of separated glucan components was determined off-line for each of the subsequently eluted 5-ml fractions. Based on the determined mass of carbohydrate for each of the fractions, elution profiles such as Fig. 16.1 were constructed. 

When this sequence is applied to carbohydrates, the first step takes place intramoleai-larly to yield a cyclic hemiacetal. The second step is intermolecular, requires an alcohol R"OH as a reactant, and proceeds readily only in the presence of an acid catalyst. An oxygen-stabilized carbocation is an intermediate. 

When ionic liquids are used as replacements for organic solvents in processes with nonvolatile products, downstream processing may become complicated. This may apply to many biotransformations in which the better selectivity of the biocatalyst is used to transform more complex molecules. In such cases, product isolation can be achieved by, for example, extraction with supercritical CO2 [50]. Recently, membrane processes such as pervaporation and nanofiltration have been used. The use of pervaporation for less volatile compounds such as phenylethanol has been reported by Crespo and co-workers [51]. We have developed a separation process based on nanofiltration [52, 53] which is especially well suited for isolation of nonvolatile compounds such as carbohydrates or charged compounds. It may also be used for easy recovery and/or purification of ionic liquids. 

Further experiments were conducted in a large aeration tank, 15 litres batch system to study die dry weight cell density, COD, carbohydrate, dissolved oxygen and oxygen transfer modelling. Two different airflow rates, 5 and 10 litres/min, were applied. However,... 

The widespread occurrence and biological significance of polyoxygenated carbocycles provided the impetus to apply RCM to sugar-derived dienes. Carbohydrate carbocyclization based on a sequence of Vasella reductive opening of iodo-substituted methyl glycosides [25], and RCM of the dienes available from the resulting unsaturated aldehydes, were used to prepare a series of natural compounds (Schemes 5-7). 

Ionophoresis of Some Carbohydrate Derivatives, A. B. Foster and M. Stacey, J. Applied Chem., 3 (1953) 19-21. 

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