Isolation and Characterisation of an Acetylated Glucomannan from Pine (Pinus silvestris L.).

Meier, Hans; Vangedal, S.

doi:10.3891/acta.chem.scand.15-1381

Cited by 49 publications

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“…The removal of the side chains by deacetylation and thus the adsorption of the linear glucomannan molecules by wood cellulose accounted for this stabilization. Glucomannan is most abundant in the secondary wall (S2) where the main part of the cellulose is also located (Meier 1961(Meier , 1962. Thus, the adsorption of the linearized glucomannan molecules by the cellulose microfibrils could be facilitated through short diffusion paths and their parallel arrangement (Stevanic and Salmén 2009).…”

Section: Introductionmentioning

confidence: 99%

Galactoglucomannan stabilization during the initial kraft cooking of Scots pine

et al. 2010

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The behaviour of wood components was studied during kraft cooking of Wiley milled Scots pine (Pinus sylvestris L.) at low temperatures characteristic for the initial phase, but comprising alkali concentrations ranging from 0.31 mol l -1 to 1.55 mol l -1 . The results confirmed the extensive dissolution/ degradation rate of galactoglucomannan (GGM) already in the beginning of a kraft cook applying standard conditions. More than 70% of GGM was eliminated along with lignin removal of approximately 30%. A relatively high GGM yield increase of almost 2.5% on o.d. (oven dry) wood has been observed when both the temperature and the alkali concentration was raised to 1308C and to approximately 1.5 mol l -1 , respectively, suggesting that stopping reactions were favoured over peeling reactions. Parallel to the pronounced stabilization of GGM, arabinoxylan experienced an additional loss of approximately 0.5-0.7% on o.d. wood, presumably owing to dissolution rather than alkaline degradation. A comprehensive kinetic model describing the alkaline degradation of GGM along with the lignin removal has been developed based on Wiley milled Scots pine raw material. The proposed kinetic model combines the alkali-dependent equilibria between ionized species of carbohydrate components with the time-dependent rate expressions of peeling, stopping, and alkaline hydrolysis. The model successfully describes the removal of GGM and lignin during initial kraft cooking. The kinetic expressions for the alkaline hydrolysis of carbohydrates were, however, less reliable owing to the limitation of the experiments to low temperatures only.

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Section: Introductionmentioning

confidence: 99%

Galactoglucomannan stabilization during the initial kraft cooking of Scots pine

et al. 2010

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“…They may also have a ~t-D-galactopyranosyl residue linked to C-6 (galactoglucomannans) (Northcote 1972) and acetyl groups linked to C-2 or C-3 of the mannose units (Meier 1961).…”

Section: Introductionmentioning

confidence: 99%

Glucomannan synthesis in pea epicotyls: The mannose and glucose transferases

Piro

Zuppa

Dalessandro

et al. 1993

Planta

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Membrane fractions and digitonin-solubilized enzymes prepared from stem segments isolated from the third internode of etiolated pea seedlings (Pisum sativum L. cv. Alaska) catalyzed the synthesis of a beta-1,4-[14C]mannan from GDP-D-[U-14C]-mannose, a mixed beta-1,3- and beta-1,4-[14C]glucan from GDP-D-[U-14C]-glucose and a beta-1,4-[14C]-glucomannan from both GDP-D-[U-14C]mannose and GDP-D-[U-14C]glucose. The kinetics of the membrane-bound and soluble mannan and glucan synthases were determined. The effects of ions, chelators, inhibitors of lipid-linked saccharides, polyamines, polyols, nucleotides, nucleoside-diphosphate sugars, acetyl-CoA, group-specific chemical probes, phospholipases and detergents on the membrane-bound mannan and glucan synthases were investigated. The beta-glucan synthase had different properties from other preparations which bring about the synthesis of beta-1,3-glucans (callose) and mixed beta-1,3- and beta-1,4- glucans and which use UDP-D-glucose as substrate. It also differed from xyloglucan synthase because in the presence of several concentrations of UDP-D-xylose in addition to GDP-D-glucose no xyloglucan was formed. Using either the membrane-bound or the soluble mannan synthase, GDP-D-glucose acted competitively in the presence of GDP-D-mannose to inhibit the incorporation of mannose into the polymer. This was not due to an inhibition of the transferase activity but was a result of the incorporation of glucose residues from GDP-D-glucose into a glucomannan. The kinetics and the composition of the synthesized glucomannan depended on the ratio of the concentrations of GDP-D-glucose and GDP-D-mannose that were available. Our data indicated that a single enzyme has an active centre that can use both GDP-D-mannose and GDP-D-glucose to bring about the synthesis of the heteropolysaccharide.

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“…The combined evidence shows that the three main hemicelluloses in the wood of amabilis fir, and probably in all other species of the genus Abies, are a water-soluble 1 arabino-4-0-meth~~lglucuronoxylan, a water-soluble galactoglucomannan, and an alkalisoluble galactoglucomannan with only a few galactose residues. One or both of the hexosans might be partly acetylated in the native state (16). The relative amount, molecular weight, and detailed structure of the polysaccharides are the same as has been previously found for corresponding hemicelluloses from the wood of other gymnosperms.…”

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Characterization of Three Hemicelluloses From the Wood of Amabilis Fir (Abies Amabilis)

Schwarz¹,

Timell²

1963

Can. J. Chem.

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An arabino-4-0-~~~ethylglucuro~~oxylan (10:14:76), a 1%-ater-soluble galactoglucon~annan (1:1:3), and an alkali-soluble galactoglucomannan (0.1:1:3) have been isolated in yields of 7 , 4 , and 87, from the wood of amabilis fir (Abies amabilis).'The structure of the polysaccharides was established by methylation and periodate oxidation techniques. The xylan (FD 106) contained side chains of (1 + 2)-linked 4-O-methy1-a-~-gl~~curonic acid and (1 -+ 3)-linked a-L-arabinofuranose residues, both attached directly to a linear framework of (1 + 4)-linked 0-D-xylose residues. The galactoglucomannans (pn 76 and 95) contained (1 -+ 6)-linked 0-D-galactopyranosyl residues attached directly to a backbone of (1 + 4)-linked p-D-mannose and p-D-glucose residues. Partial hydrolysis of the two hexosans yielded 10 and 13 oligosaccharides, respectively, containing ( I -+ 4)-p-D-mannose, (1 + 4)-P-~-glucose, and (1 -+ 6)-a-D-galactopyra~~ose residues. The ~nolecular rotations of a series of mannooligosaccharides corresponded t o a value of -54" for the specific rotation of an infinitely long mannan. I t is concluded that the main hernicelluloses it1 amabilis fir wood are the same as those occurring in the wood of gymnosperms from other genera. The same three hemicelluloses are also present in the bark of this species.Among the gymnosperms, members of the genera Ginkgo, Larix, Picea, Pinus, Thuja, and Tsuga have been extensively studied with regard to their main hemicellulose constituents (1). No member of the genus Abies, however, has so far been similarly investigated although inany fir species are both widespread and valuable. The present investigation is concerned with the isolation and constitution of the three principal hemicelluloses in the wood of amabilis fir (Abies amabilis) (Douglas) Forbes). The polysaccharides occurring in the bark of this tree have previously been examined in detail (2, 3). RESULTS AND DISCUSSIOXWhen amabilis fir wood was partially hydrolyzed, the acid portion of the hydrolyzate consisted of galacturonic acid, 4-0-methylglucuronic acid, a galacturonosyl rhamnose, probably admixed with a galacturonosyl glucose, and a 4-0-methylglucuronosyl xylose. The first aldobiouronic acid has previously been isolated from pine wood (4, 5 ) . The third was fully identified as 2-0-(4-0-methyl-a-D-glucosyluronic acid)-D-XI-lopyranose. I t probably originated from the xylan portion of the mood.For isolation of the hemicelluloses, the wood was partially delignified with chlorous acid and the holocellulose was extracted with aqueous potassium hydroxide, giving tu.0 polysaccharides, which were separated by repeated treatment with barium hydroxide. lPresent address: E. I. du Pont de iVenzours and Coi?zpany, Kinston, N.C. 2Present adduess:

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Isolation and Characterisation of an Acetylated Glucomannan from Pine (Pinus silvestris L.).

Cited by 49 publications

References 0 publications

Galactoglucomannan stabilization during the initial kraft cooking of Scots pine

Galactoglucomannan stabilization during the initial kraft cooking of Scots pine

Glucomannan synthesis in pea epicotyls: The mannose and glucose transferases

Characterization of Three Hemicelluloses From the Wood of Amabilis Fir (Abies Amabilis)

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