Pentose sugar

C. The pentose sugar of straw, cotton-seed hulls and various hemicelluloses, and of some glycosides, including the primeverosides. It is not fermentable and behaves chemically as other sugars. 

C. uti/is yeast is produced by either fed-batch or continuous processes. Aerated-agitated fermentors range up to 300 m total capacity and ate operated in the same manner as described for S. cerevisiae (2,5). C. utilis is capable of metabolizing both hexose and pentose sugars. Consequendy, papermiU wastes such as sulfite waste Hquot that contain these sugars often ate used as substrates. 

Note that in this scheme, the six hexose sugars have been converted to six pentose sugars with release of six molecules of COg, and the six pentoses are reconverted to five glucose molecules. 

False. D-xylose is a pentose sugar which are very rarely found in microbial exopolysaccharides. 

A pentose sugar. In RNA the sugar is ribose, and in DNA the sugar is deoxyribose, a ribose in which one OH group has been replaced with one H atom (Figure 13-231. 

Sulfur compounds such as furfuryl mercaptans have a rotten odor but in small amounts are coffee-like.15 Furfuryl mercaptan itself has an odor threshold of 0.005 ppb in water but at 10 ppb in water it imparts a distinctly stale odor.19 The particular precursors of furfuryl mercaptan seem to be the coffee cell wall material which contains both arabinogalactan as a pentose sugar source and protein such as glutathione.84 Other sulfur compounds such as kahweofuran and methyldithiofurans impart a meaty odor if their concentrations are high enough.19... 

The compactness and complexity of (ligno)cellulose makes it much more difficult to attack by enzymes with respect to starch. Therefore, the cost of bioethanol production is higher [23], To be cost competitive with grain-derived ethanol, the enzymes used for biomass hydrolysis must become more efficient and far less expensive. In addition, the presence of non-glucose sugars in the feedstock complicates the fermentation process, because conversion of pentose sugars into ethanol is less efficient than conversion of the hexose sugars. 

The enzymes GSH peroxidase, GSH reductase and SOD collaborate to ensure that the red cell is protected from the effects of methaemoglobin and superoxide. Disposal of hydrogen peroxide may occur by catalase, in a reaction which is also dependent on NADPH. This vital coenzyme is provided via the PPP. Although the PPP operates in all cell types for the provision of pentose sugars and nucleotides, its role in the RBC is more directed to cell survival than cell division. 

Tauber test (analy chem) A color test for identification of pentose sugars the sugars produce a cherry-red color when heated with a solution of benzidine in glacial acetic acid. tau-bor, test ... 

The pentose sugars, as well as the hexoses, are utilized by acetone-and butyl alcohol-producing organisms. Partansky and Henry reported the production of butanol and acetone from wood sugars. This work was continued in the laboratory of W. H. Peterson of the University of Wisconsin. Tables VIII and IX summarize their findings with two organisms. 

Pentose sugars in still residues from alcohol production were utilized to the extent of 90% in this equipment. 

The Coffee (syn. Madder) botanical family (Rubiaceae Juss.) (Table 15) consists of more than 400 genera and over 6000 species. It grows in the tropics and the sub-tropics. Plants belonging to this family include trees, bushes and liane. The Coffee plant family contains two major purines of adenine- /guanine-derived alkaloids, the so-called purine alkaloids . Purine is a nitrogenous base of nucleotide, which consists of just purine and pentose sugar (o-ribose or 2 deoxy-D-ribose). Typical purine alkaloids are caffeine, theophylline and theobromine. The same or similar purine alkaloids occur also in other plant families. 

A pentose sugar i.e., D( ribose or 2-deoxyribose (furanose form). 

Hi) Phosphoric acid Nucleotides are the phosphoric acid esters of nucleosides (nucleosides contain only pentose sugar and a nitrogen base). 

ATP Regarded as Store House of Energy Adenosine triphosphate (ATP) in a nucleotide consists of purine base adenine, a pentose sugar ribose and three molecules of phosphate. It contains two oxygen to phosphorus bonds between two phosphate units. These phosphorus bonds are called high energy phosphatic bonds. 

Nucleotides are the phosphoric acid ester of nucleoside, while nucleosides are compounds in which nitrogenous bases (purines and pyrimidines) are conjugated to the pentose sugar (ribose or deoxyribose) by a b-glycosidic linkage. AMP, ATP, ADP, GMP, CMP, UMP are the examples of mononucleotides. 

Furfural comes from pentose sugars in cereal straws and brans. Furfural is the precursor of furfuryl mercaptan and its disulfide, difurfuryl disulfide, which are both important chemicals for coffee, meat and roasted flavours. They are prepared by the reaction of furfural and hydrogen sulfide (Scheme 13.15). 

Furan is synthesized by decarbonylation of furfural (furfuraldehyde), which itself can be prepared by acidic dehydration of the pentose sugars found in oat hulls, corncobs and rice hulls. 

Absorption spectra of the phenol-sulfuric acid solutions tested for total sugars show that 5-hydroxymethylfurfural from hexoses is more common in the uppermost Silurian and Devonian samples than in the earlier deposits. Furfurals from pentose sugars evidently form the bulk of the residual carbohydrates in these samples, however. There is no definite evidence as to the marine or terrestrial origin of the hexose products in the samples. 

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