PURIFICATION AND COMPOSITION OF A POLYURONIDE HEMICELLULOSE ISOLATED FROM WHEAT STRAW

1952 ◽  
Vol 30 (7) ◽  
pp. 515-521 ◽  
Author(s):  
G. A. Adams ◽  
A. E. Castagne
Keyword(s):  
Petroleum Ether ◽  
Wheat Straw ◽  
Intrinsic Viscosity ◽  
Uronic Acid ◽  
Chloroform Solution ◽  
Degree Of Polymerization ◽  
Hot Water ◽  
Molar Ratio ◽  
Fractional Precipitation ◽  
Homogeneous Fraction

A homogeneous polyuronide hemicellulose has been prepared from a crude hemicellulose isolated from wheat straw holocellulose by hot water. The method of preparation consisted of fractional precipitation of the acetylated hemicellulose from chloroform solution by petroleum ether. Approximately 50% of the recovered fractions consisted of a polysaccharide made up of 28 moles of D-xylose, 5 moles of L-arabinose, and 3 moles of uronic acid and having an [Formula: see text] and a molar ratio, methoxyl: uronic anhydride, of approximately 1.0. Intrinsic viscosity measurements indicated a degree of polymerization of approximately 30. Separation of hexosans present in the original hemicellulose showed that they were not chemically combined with the main pentosan fraction. They were recovered admixed with short chain pentosan material containing a higher proportion of arabinose to xylose than the main homogeneous fraction.

HEMICELLULOSES OF WHEAT STRAW

1951 ◽  
Vol 29 (2) ◽  
pp. 109-122 ◽  
Author(s):  
G. A. Adams ◽  
A. E. Castagne
Keyword(s):  
Wheat Straw ◽  
Potassium Hydroxide ◽  
Uronic Acid ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Hot Water ◽  
Acid Complex ◽  
Main Fraction ◽  
Hydrolysis Of ◽  
Soluble Fractions

Various hemicellulose fractions were extracted from wheat straw holocellulose (extractive and pectin free) by successive treatments with cold and hot water, 0.5%, 1.0%, and 2.0% potassium hydroxide and were recovered by precipitation with alcohol. Approximately 25% of the holocellulose material was removed, one half being in the hot water soluble fraction. The original holocellulose, the extracted residue, and the recovered fractions were analyzed for pentosan, uronic acid anhydride, acetyl, methoxyl, and ash content. In general, the more soluble fractions had a higher uronic acid and methoxyl content; the less soluble had a higher pentosan content and a more negative rotation [Formula: see text]. Intrinsic viscosity measurements indicated that all fractions had a degree of polymerization of 25–30. Hydrolysis of the main fraction yielded D-xylose, L-arabinose, D-glucose; in addition D-galactose was found in the water soluble fractions. Quantitative determinations of the sugars in the hydrolyzates showed that D-xylose predominated, with L-arabinose, D-glucose, and D-galactose (when present) in progressively smaller amounts. On hydrolysis all fractions yielded an acid-resistant uronic acid complex that contained D-xylose and a uronic acid tentatively identified as monomethoxyl galacturonic acid.

CONSTITUTION OF A WATER SOLUBLE HEMICELLULOSE FROM AMERICAN BEECHWOOD (FAGUS GRANDIFOLIA)

1957 ◽  
Vol 35 (6) ◽  
pp. 556-564 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Average Molecular Weight ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Fagus Grandifolia ◽  
Water Soluble ◽  
Hot Water ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Homogeneous Fraction ◽  
Hydrolysis Of

Extraction of beechwood chlorite holocellulose with hot water yielded a hemicellulose in 13.4% yield (based on original extractive-free wood) containing D-xylose 72%, D-galactose 11.0%, and uronic acid 13.2%. Purification of the crude hemicellulose by complexing with Fehling's solution yielded a chemically homogeneous fraction containing D-xylose 83% and 4-O-methyl-D-glucuronic acid 15.5%. Hydrolysis of the fully methylated hemicellulose yielded 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 3-O-methyl-D-xylose, and 3-O-methyl-2-O-(2,3,4-tri-O-methyl-D-glucopyranosyluronic acid)-D-xylose in a molar ratio of 2:35:3:5. On the basis of the methylation data, periodate oxidation, reducing power determinations, and weight average molecular weight values a possible structure for the hemicellulose is proposed.

CUPRIETHYLENEDIAMINE AS A REAGENT FOR HEMICELLULOSE SEPARATION FROM WHEAT STRAW HOLOCELLULOSE

1951 ◽  
Vol 29 (11) ◽  
pp. 974-985
Author(s):  
V. D. Harwood
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Petroleum Ether ◽  
Wheat Straw ◽  
Periodate Oxidation ◽  
Chloroform Solution ◽  
Chemical Compositions ◽  
Distillation Method ◽  
Molecular Weights ◽  
Isothermal Distillation

Wheat straw and wheat straw holocellulose were dispersed in aqueous cupriethylenediamine solutions and fractionated by graded precipitation with acid and alcohol. From the holocellulose a 25.4% recovery of a hemicellulose containing negligible quantities of hexoses was achieved. The corresponding product from wheat straw was contaminated with both lignin and cellulose but a comparison of the chemical compositions of the two hemicelluloses showed that the acid chlorite used for delignification had caused very little hydrolytic action. The acetate of the hemicellulose from holocellulose was fractionated from chloroform solution by the addition of petroleum ether into a series of fractions and subfractions. Analysis of representative fractions from this series led to the conclusion that the hexoses present were not chemically combined with pentosan. Molecular weights were determined by periodate oxidation, the Signer isothermal distillation method, and from the lowering of the vapor pressure of their chloroform solutions and showed that the hemicellulose molecules were relatively small (mol. wt. < 10,000). The decreasing ratio of xylose to arabinose in the fractions of lower molecular weight indicated increasing chain branching.

CONSTITUTION OF THE HEMICELLULOSE FROM MESTA FIBER (HIBISCUS CANNABINUS)

1963 ◽  
Vol 41 (9) ◽  
pp. 2346-2350 ◽  
Author(s):  
S. K. Sen
Keyword(s):  
Molecular Weight ◽  
Uronic Acid ◽  
Average Molecular Weight ◽  
Analytical Data ◽  
Degree Of Polymerization ◽  
Hibiscus Cannabinus ◽  
Molar Ratio ◽  
Alkaline Solutions ◽  
Number Average Molecular Weight ◽  
Hydrolysis Of

The chlorite holocellulose of mesta fiber (Hibiscus cannabinus) was extracted with alkaline solutions of successively increasing concentration and finally with alkaline borate solution. Hemicellulose fractions (I–IV) were thus obtained. Analytical data are recorded for each fraction.Partial acid hydrolysis of the mesta hemicellulose gave 2-O-(4-O-methyl-α-D-glucopyranosyl uronic acid)-D-xylopyranose. Methanolysis and hydrolysis of the fully methylated hemicellulose (fraction II) gave a mixture of 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyl uronic acid)-3-O-methyl-D-xylopyranose in the approximate molar ratio of 1.6:34:1:6.4. The number-average molecular weight of the methylated polysaccharide was 18,400 ± 500 (degree of polymerization, 110 ± 3). The number-average molecular weight of the original hemicellulose (fraction II) was found to be 23,000 ± 500 (degree of polymerization, 164 ± 3). On the basis of this and other evidences it is suggested that the polysaccharide is composed of chains of 144 (1 → 4)-linked β-D-xylopyranose residues having approximately every seventh residue carrying a terminal 4-O-methyl-α-D-glucuronic acid residue linked through position 2. A small degree of branching in the backbone of D-xylose is indicated.

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 POLYURONIDE HEMICELLULOSE FROM WHEAT STRAW

1952 ◽  
Vol 30 (9) ◽  
pp. 698-710 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Wheat Straw ◽  
Uronic Acid ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Molar Ratio ◽  
Acid Complex ◽  
Glycosidic Bonds ◽  
A Chain ◽  
End Group

The structure of a polyuronide hemicellulose from wheat straw containing xylose, arabinose, and hexuronic acid units has been investigated. Graded hydrolysis preferentially removed anhydro-L-arabinose units leaving a xylan to which uronic acid units were attached. Methylation and hydrolysis yielded 2,3,4-trimetliyl xylose (2.7%) indicating one nonreducing end group per 37 units; 2,3,5-trimethyl-L-arabinose, 2,3-dimethyl-D-xylose, and 2-methyl-D-xylose were found in a molar ratio 1:5:1. In addition, a methylated uronic acid complex was recovered which on extensive hydrolysis yielded an aldobiuronic acid. The latter, on reduction with sodium borohydride, yielded 2,3,4-trimethyl glucose (1 mole) and 2-methyl xylose (1 mole); the structure 2-methyl 3[2,3,4-trimethyl α-D-glucuronosido] D-xylose was therefore indicated for the methylated aldobiuronic acid.A structure for the hemicellulose is proposed which consists of approximately 32 anhydro-D-xylose units linked β 1,4- in a chain to which five anhydro-L-arabinose and three D-glucuronic acid units are attached as side groups by 1,3-glycosidic bonds. Results of periodate oxidation and estimation of reducing power support the proposed structure.

Synthesis and Characterization of Copolymer of Dimethyldiallylammonium Chloride and Acrylamide

2006 ◽  
Vol 11-12 ◽  
pp. 753-756 ◽  
Author(s):  
Fu Mei Wu ◽  
Xing Ying Zhang
Keyword(s):  
Petroleum Ether ◽  
Emulsion Polymerization ◽  
Intrinsic Viscosity ◽  
Ir Spectrum ◽  
Tween 80 ◽  
Redox System ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Inverse Emulsion Polymerization

The inverse emulsion polymerization of dimethyldiallylammonium chloride (DMDAAC) with acrylamide (AM) was carried out using a redox system as initiator, petroleum ether as oil, and Span-85 and Tween-80 as emulsifiers. The cationic degree of the copolymer increased markedly when AM was fed into the system in batch. The effect of DMDAAC content on the intrinsic viscosity ([η]) and solubility of the copolymer, and the methods of feeding AM on the cationic degree and solubility of the copolymer was studied in this work. The cationic degree of 39.8% of the copolymer was achieved. When the molar ratio of AM to DMDAAC was 4.0, the copolymer with [η] of 10.02 dl/g and the dissolving time less than 15min was obtained. The structure of the copolymer was also characterized by IR spectrum.

scholarly journals Polysaccharide Derived from Nelumbo nucifera Lotus Plumule Shows Potential Prebiotic Activity and Ameliorates Insulin Resistance in HepG2 Cells

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1780
Author(s):  
Bao Le ◽  
Pham-Thi-Ngoc Anh ◽  
Seung-Hwan Yang
Keyword(s):  
Insulin Resistance ◽  
Hepg2 Cells ◽  
Structural Characteristics ◽  
Physicochemical Characterization ◽  
Deae Cellulose ◽  
Hot Water ◽  
Nelumbo Nucifera ◽  
Molar Ratio ◽  
Prebiotic Activity ◽  
Insulin Resistant

Polysaccharides are key bioactive compounds in lotus plumule tea, but their anti-diabetes activities remain unclear. The purpose of this study was to investigate the prebiotic activities of a novel polysaccharide fraction from the Nelumbo nucifera lotus plumule, and to examine its regulation of glucose metabolism in insulin-resistant HepG2 cells. The N. nucifera polysaccharide (NNP) was purified after discoloration, hot water extraction, ethanol precipitation, and DEAE-cellulose chromatography to obtain purified polysaccharide fractions (NNP-2). Fourier transform infrared spectroscopy was used to analyze the main structural characteristics and functional group of NNP-2. Physicochemical characterization indicated that NNP-2 had a molecular weight of 110.47 kDa and consisted of xylose, glucose, fructose, galactose, and fucose in a molar ratio of 33.4:25.7:22.0:10.5:8.1. The prebiotic activity of NNP-2 was demonstrated in vitro using Lactobacillus and Bifidobacterium. Furthermore, NNP-2 showed bioactivity against α-glucosidase (IC50 = 97.32 µg/mL). High glucose-induced insulin-resistant HepG2 cells were used to study the effect of NNP-2 on glucose consumption, and the molecular mechanism of the insulin transduction pathway was studied using RT-qPCR. NNP-2 could improve insulin resistance by modulating the IRS1/PI3K/Akt pathway in insulin-resistant HepG2 cells. Our data demonstrated that the Nelumbo nucifera polysaccharides are potential sources for nutraceuticals, and we propose functional food developments from the bioactive polysaccharides of N. nucifera for the management of diabetes.

Optimizing Liquid Hot Water pretreatment conditions to enhance sugar recovery from wheat straw for fuel-ethanol production

Fuel ◽  
2008 ◽  
Vol 87 (17-18) ◽  
pp. 3640-3647 ◽  
Author(s):  
J.A. Pérez ◽  
I. Ballesteros ◽  
M. Ballesteros ◽  
F. Sáez ◽  
M.J. Negro ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Wheat Straw ◽  
Fuel Ethanol ◽  
Hot Water ◽  
Sugar Recovery ◽  
Liquid Hot Water Pretreatment ◽  
Liquid Hot Water ◽  
Water Pretreatment ◽  
Pretreatment Conditions ◽  
Hot Water Pretreatment

AMMONOLYSIS OF URONIC ESTER GROUPS IN BIRCH XYLAN

1964 ◽  
Vol 42 (11) ◽  
pp. 2434-2439 ◽  
Author(s):  
Paul Y. Wang ◽  
H. I. Bolker ◽  
C. B. Purves
Keyword(s):  
Alkaline Hydrolysis ◽  
Uronic Acid ◽  
Liquid Ammonia ◽  
Treated Wood ◽  
Hot Water ◽  
Amide Nitrogen ◽  
White Birch

Solvent-extracted white birch, kept near 20° in liquid ammonia under pressure for 72 h and then extracted with methanol to remove acetamide, retained 0.25% of amide nitrogen. Extraction of the very finely ground residual wood with hot water yielded 21% as a 4-O-methylglucuronoxylan containing 0.53% of amide nitrogen. Alkaline hydrolysis removed the amide absorption in the infrared and restored the normal xylan spectrum. These results, supported by various control experiments, showed that amide groups in the ammonia-treated wood were derived from lactone or ester groups in the original 4-O-methylglucuronoxylan. Some of the uronic acid groups in the native wood presumably existed as ester crosslinks.

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