scholarly journals Plant mucilages. XXIII. Partial hydrolysis of Abelmoschus-mucilage M and the structural features of its polysaccharide moiety.

1979 ◽  
Vol 27 (7) ◽  
pp. 1651-1656 ◽  
Author(s):  
MASASHI TOMODA ◽  
YOKO SUZUKI ◽  
NORIKO SATOH
Keyword(s):  
Structural Features ◽  
Partial Hydrolysis ◽  
Hydrolysis Of

Some structural features of the heteropolysaccharides of Candida bogoriensis

1968 ◽  
Vol 46 (21) ◽  
pp. 3407-3411 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer
Keyword(s):  
Main Chain ◽  
Glucuronic Acid ◽  
Structural Features ◽  
Side Chain ◽  
Partial Hydrolysis ◽  
Exocellular Polysaccharides ◽  
Hydrolysis Of

The two exocellular polysaccharides of Candida bogoriensis contain D-mannose, D-fucose, L-rhamnose, D-glucuronic acid, and D-galactose residues. The main heteropolymer (> 80%) has an α-D-(1 → 3)-linked mannan main-chain as shown by successive Smith degradations. Partial hydrolysis of the heteropolymers provided several methylpentose-containing oligosaccharide fragments corresponding to possible side-chain components.

Local Structure of Ferrihydrite and Feroxyhite by Exafs Spectroscopy

Clay Minerals ◽  
1993 ◽  
Vol 28 (2) ◽  
pp. 165-184 ◽  
Author(s):  
A. Manceau ◽  
V. A. Drits
Keyword(s):  
Local Structure ◽  
Temperature Stability ◽  
Coherent Scattering ◽  
Structural Features ◽  
Exafs Spectroscopy ◽  
Partial Hydrolysis ◽  
Ferric Nitrate ◽  
Static Disorder ◽  
Local Structures ◽  
Hydrolysis Of

AbstractSynthetic 2-line and 6-line ferrihydrite and feroxyhite samples prepared from ferric salt solutions have been investigated by EXAFS spectroscopy. All these materials have been found to be short-range ordered, consisting of Fe octahedra linked by comers, edges, and faces. Their local structures are related to those of well-crystallized (oxyhydr)oxides, and the absence of hkl reflections in some samples is attributed to the small size of coherent scattering domains. The presence of face sharings indicates that these materials have structural similarities with hematite. Based on Fe-Fe distances and the analysis of the static disorder, it has been concluded that the local structure of feroxyhite is close to that of hematite, whereas ferrihydrite has common structural features with both hematite (αFe203) and cdβFeOOFI. The local structure of ferrihydrite thus differs from that of aqueous Fe polymers obtained by the partial hydrolysis of ferric nitrate and chloride solutions. Differences of local structures among hydrous Fe oxides and aqueous polymers have been interpreted on the basis of a room temperature stability phase diagram established for well-crystallized (oxyhydr)oxides.

scholarly journals Studies of lipid A fractions from the lipopolysaccharides of Pseudomonas aeruginosa and Pseudomonas alcaligenes

1973 ◽  
Vol 133 (3) ◽  
pp. 563-572 ◽  
Author(s):  
David T. Drewry ◽  
James A. Lomax ◽  
George W. Gray ◽  
Stephen G. Wilkinson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Gel Filtration ◽  
Structural Features ◽  
Partial Hydrolysis ◽  
Hexadecanoic Acid ◽  
Alkaline Methanolysis ◽  
Pseudomonas Alcaligenes ◽  
Hydrolysis Of ◽  
Derivatives Of

Lipid A fractions from Pseudomonas aeruginosa and Pseudomonas alcaligenes have similar compositions and structural features. By means of hydrazinolysis of the parent lipopolysaccharides and partial hydrolysis of the deacylation products, it was established that both lipids are derived from the β-(1→6)-linked disaccharide of glucosamine. Phosphorylated derivatives of the disaccharide from Ps. aeruginosa were also characterized. The lipids differ mainly in the absence of hexadecanoic acid and 2-hydroxydodecanoic acid from the lipid from Ps. alcaligenes. Evidence that in Ps. aeruginosa these acids are ester-linked to residues of 3-hydroxyalkanoic acids (including 3-hydroxydecanoic acid) was obtained. Heterogeneity of lipid A fractions was indicated by t.l.c., and by gel filtration of de-O-acylation products from mild alkaline methanolysis of the lipids.

THE STRUCTURE OF A SYNTHETIC GLUCAN: I. GENERAL STRUCTURAL FEATURES

1962 ◽  
Vol 40 (6) ◽  
pp. 1196-1200 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau
Keyword(s):  
Petroleum Ether ◽  
Acid Hydrolysis ◽  
Direct Evidence ◽  
Periodate Oxidation ◽  
Structural Features ◽  
Degree Of Polymerization ◽  
Molar Ratio ◽  
Partial Hydrolysis ◽  
Large Numbers ◽  
Hydrolysis Of

Only D-glucose was obtained on acid hydrolysis of the glucan. Periodate oxidation released formaldehyde, which was believed to arise from C6 of D-glucofuranose units. From the additional formaldehyde liberated from the borohydride-reduced glucan the degree of polymerization was estimated to be about 165. Complete hydrolysis of the derived polyalcohol gave glycerol, erythritol, D-glucose, and D-xylose. Partial hydrolysis gave glycerol, erythritol, and at least seven non-reducing oligosaccharides. Direct evidence for the existence of relatively large numbers of 1 → 6 and 1 → 4 linkages was found, together with smaller numbers of 1 → 2 linkages. The methylated glucan was freely soluble in chloroform – petroleum ether (5:95), and hydrolysis gave tetra, tri, di, and mono-O-methyl-D-glucoses in a 6:6:3:1 molar ratio.

THE CONSTITUTION OF A SYNTHETIC XYLAN: I. GENERAL STRUCTURAL FEATURES

1962 ◽  
Vol 40 (8) ◽  
pp. 1479-1482 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau
Keyword(s):  
Infrared Spectrum ◽  
Ethylene Glycol ◽  
Periodate Oxidation ◽  
Phosphorous Acid ◽  
Structural Features ◽  
Synthetic Polymer ◽  
Partial Hydrolysis ◽  
Complete Hydrolysis ◽  
Carbonyl Band ◽  
Hydrolysis Of

The polysaccharide was obtained by polymerization of D-xylose at 140 °C in the presence of phosphorous acid. Complete hydrolysis of the xylan followed by bromine oxidation showed that the synthetic polymer contained only xylose. Periodate oxidation resulted in formation of a considerable quantity of formaldehyde, the origin of which is not known. Periodate oxidation of borohydride-reduced xylan gave additional formaldehyde and, from this, the average D. P. of the polymer was estimated to be about 55. Complete hydrolysis of the polyalcohol gave ethylene glycol, glycerol, and xylose in a ratio of 2:9:1. Partial hydrolysis gave ethylene glycol, glycerol, and at least seven non-reducing components. Hydrolysis of the fully methylated xylan gave tri-, di-, mono-methyl xyloses and xylose in a 32:32:18:5 ratio, and a carbonyl band was evident in the infrared spectrum of the hydrolyzate. No such band was evident in the hydrolyzate of the unsubstituted xylan. The xylan is highly branched and contains some D-xylofuranose units.

Organic material dissolved during oxygen-alkali pulping of hot water extracted birch sawdust

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 237-244 ◽  
Author(s):  
JONI LEHTO ◽  
RAIMO ALÉN
Keyword(s):  
Acetic Acid ◽  
Betula Pendula ◽  
Cooking Time ◽  
Hot Water ◽  
Partial Hydrolysis ◽  
Chemical Pulping ◽  
Black Liquors ◽  
Aliphatic Carboxylic Acids ◽  
Hydrolysis Of ◽  
Cooking Conditions

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.

THE ALDOBIOURONIC ACIDS OF HEMICELLULOSE B OF OAT HULLS

1956 ◽  
Vol 34 (3) ◽  
pp. 338-344 ◽  
Author(s):  
E. L. Falconer ◽  
G. A. Adams
Keyword(s):  
Glucuronic Acid ◽  
The Other ◽  
Partial Hydrolysis ◽  
Oat Hulls ◽  
Hydrolysis Of

Partial hydrolysis of hemicellulose B from oat hulls yielded two aldobiouronic acids, which were identified as 2-O-(4-O-methyl-α-D-glucopyruronosyl)-D-xylose and 2-O-(α-D-glucopyruronosyl)-D-xylose respectively. In addition, two aldotriouronic acids were isolated, one yielding on hydrolysis xylose and 4-O-methyl-glucuronic acid, and the other, xylose, galactose, and glucurone.

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