Aspect of Native and Redeposited Xylans at the Surface of Cellulose Microfibrils

Mora, Fernando Cobos; Ruel, K.; Comtat, J.; Joseleau, J.P.

doi:10.1515/hfsg.1986.40.2.85

Cited by 60 publications

(40 citation statements)

References 7 publications

(5 reference statements)

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“…This was typically shown in the case of nascent bacterial cellulose where the significant adsorption of soluble xylan on the emerging cellulose prevented the coalescence of cellulose elementary fibrils into the classical bacterial cellulose ribbons (Tokoh et al 2002a, b;Winter et al 2006). In other reports, ultrastructural observations have shown how smooth cellulose microfibrils became decorated by an abundant precipitate after interaction with xylan in solution (Henriksson and Gatenholm 2001;Linder et al 2003;Mora et al 1986). Finally, the best example of xylan affinity for cellulose is observed in the case of quince slime where the native individual cellulose microfibrils are so tightly coated by a glucuronoxylan rich in glucosyluronic acid (Lindberg et al 1990), that the microfibrils do not stick to one another any more and thus are free to get organized into a remarkable cholesteric system within the epidermal tissue of the quince seed (Vian et al 1994;Willison and Abeysekera 1988).…”

Section: Discussionmentioning

confidence: 91%

The molecular basis of the adsorption of xylans on cellulose surface

Mazeau

Charlier

2012

Cellulose

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In order to model the adsorption of xylan on cellulose, we have simulated, at the atomic level, the gas phase adsorption of small xylan fragments having 5 skeletal b (1 ? 4) xylosyl residues (X 5 ), using molecular dynamics simulations. A first regime was considered, corresponding to a low surface coverage, with the adsorption of isolated X 5 in various initial orientations. In this regime, the simulation indicated that X 5 moved toward extended conformations, some of them being helical, with the possibility of either 2 1 or left-handed 3 1 helices. During the simulation, the X 5 fragments became preferentially oriented, parallel or anti parallel with respect to the cellulose chain axis. Substitution of the X 5 backbone by either GlcA and/or Araf side chains had no major influence on either the conformation or the efficiency of the interaction. However, the presence of side chains favored orientations of the X 5 backbone inclined with respect to the cellulose chain axis. In a second regime corresponding to monolayer coverage, the geometrical features of the adsorption of the xylan fragments on cellulose was roughly the same as that in the individual coverage situation. In this case, the monolayer became equilibrated at 0.14 g of xylan fragments for each g of cellulose, a figure that compared favourably with the values obtained in experimental adsorption of xylan on bacterial cellulose.

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Section: Discussionmentioning

confidence: 91%

The molecular basis of the adsorption of xylans on cellulose surface

Mazeau

Charlier

2012

Cellulose

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“…An investigation on the solution behaviour of 4-O-methyl glucuronoxylans concluded that the reason for aggregation was not dependent on the molecular weight, but on the chemical structure (Saake et al 2001;Esker et al 2004). Two basic mechanisms of the agglomeration have basically been suggested: hydrogen bonds between linear portions of polysaccharide chains (Richards and Blake 1971;Mora et al 1986;Linder et al 2003), and interactions between hydrophobic substituents, e.g., lignin bonded to the polysaccharide chain (Saake et al 2001;Esker et al 2004;Gradwell et al 2004;Roubroeks et al 2004;Linder et al 2003). The presence of hydrophobic groups on the hydrophilic main chain is a frequent explanation for the self assembly process of polymers in aqueous solutions (Akiyoshi et al 1993;Nichifor et al 1999;Esquenet and Buhler 2001;Cochin et al 2001).…”

Section: Introductionmentioning

confidence: 99%

The influence of lignin on the self-assembly behaviour of xylan rich fractions from birch (Betula pendula)

et al. 2007

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A crude xylan isolate obtained by prehydrolysis and mild alkaline extraction from birch wood chips (Betula pendula), and a carefully delignified xylan fraction from the same source, were examined by dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryo-TEM) with regard to their propensity to self-assemble in water into insoluble aggregates. The delignification involved the extraction with chloroform of a crude xylan solution in a pyridine/acetic acid/water mixture. It resulted in a purified xylan fraction in a yield of 23% in which 75 and 90% of the lignin had been removed as indicated by Klason and UV-determination, respectively. It was found that both xylan fractions formed agglomerates by self-assembly in water. However, DLS and cryo-TEM indicated that the aggregates were larger in size (90 vs. 40 nm) and greater in mass when more lignin was present. The addition of an alkaline solution of isolated lignin (obtained by steam explosion) to increasing concentrations of a delignified xylan revealed increasing turbidity. Our conclusion is that lignin induces agglomeration of xylan in aqueous solutions, but xylan concentration plays an active role in the aggregation phenomena. An agglomeration mechanism for lignin rich xylan fractions is proposed.

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“…They are composed of a linear backbone of ~-(1,4)-linked-D-xylopyranose and irregularly substituted at O-2 position by 4-O-methyl-c~-D-glucuronic acid (Fengel and Wegener 1989). GXs can tightly bind to cellulose microfibrils because of the hydrogen bonding between the xylan backbone and the glucan chain of cellulose microfibrils (Labavitch and Ray 1974, McNeil et al 1975, Mora et al 1986, Neville 1988, Joseleau etal. 1991.…”

Section: Introductionmentioning

confidence: 99%

Localization of glucuronoxylans in Japanese beech visualized by immunogold labelling

1998

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Summary. An antiserum against glucuronoxylans (GXs) has been raised from a mouse. The dot-blot immunoassay and competitive inhibition test indicated that the antibodies could bind specifically to GXs. Therefore, the antiserum was used for immunogold labelling to investigate the localization of GXs in Japanese beech. Labelling of GXs was seen only in the secondary wails of xylem cells, but not in the primary walls or the middle lamella. GXs were evenly distributed in the secondary walls except for the outer part of the outer secondary-wall layer in which they were less abundant. The labelling density in each secondary-wall layer (S 1, $2, and $3) increased during cell wall formation. This result strongly suggests that the deposition of GXs occurs in a penetrative way.

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Aspect of Native and Redeposited Xylans at the Surface of Cellulose Microfibrils

Cited by 60 publications

References 7 publications

The molecular basis of the adsorption of xylans on cellulose surface

The molecular basis of the adsorption of xylans on cellulose surface

The influence of lignin on the self-assembly behaviour of xylan rich fractions from birch (Betula pendula)

Localization of glucuronoxylans in Japanese beech visualized by immunogold labelling

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