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Duchesne, Isabelle; Hult, Eva Lena; Molin, Ulrika; Daniel, Geoffrey; Iversen, Tommy; Lennholm, Helena

doi:10.1023/a:1016645809958

Cited by 157 publications

(65 citation statements)

References 19 publications

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“…One can thus envision that removing large amounts of the hemicellulose fraction by diluteacid pretreatment leaves the remaining lignin as the primary barrier between the partially exposed cellulose microfibrils. Thus, one interpretation of our results is that in the absence of hemicelluloses, lignin acts as a spacer between the cellulose microfibrils and that removing the lignin allows neighboring cellulose fibrils to aggregate (Duchesne et al 2001;Oksanen et al 1997). In this scenario, the microfibril structure collapses in a manner analogous to the effect caused by drying biomass or cellulose, thereby limiting cellulase action (Jeoh et al 2007).…”

Section: Discussionmentioning

confidence: 74%

Can delignification decrease cellulose digestibility in acid pretreated corn stover?

et al. 2009

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It has previously been shown that the improved digestibility of dilute acid pretreated corn stover is at least partially due to the removal of xylan and the consequent increase in accessibility of the cellulose to cellobiohydrolase enzymes. We now report on the impact that lignin removal has on the accessibility and digestibility of dilute acid pretreated corn stover. Samples of corn stover were subjected to dilute sulfuric acid pretreatment with and without simultaneous (partial) lignin removal. In addition, some samples were completely delignified after the pretreatment step using acidified sodium chlorite. The accessibility and digestibility of the samples were tested using a fluorescence-labeled cellobiohydrolase (Trichoderma reesei Cel7A) purified from a commercial cellulase preparation. Partial delignification of corn stover during dilute acid pretreatment was shown to improve cellulose digestibility by T. reesei Cel7A; however, decreasing the lignin content below 5% (g g -1 ) by treatment with acidified sodium chlorite resulted in a dramatic reduction in cellulose digestibility. Importantly, this effect was found to be enhanced in samples with lower xylan contents suggesting that the near complete removal of xylan and lignin may cause aggregation of the cellulose microfibrils resulting in decreased cellulase accessibility.

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Section: Discussionmentioning

confidence: 74%

Can delignification decrease cellulose digestibility in acid pretreated corn stover?

et al. 2009

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“…A substantial amount of xylose (13.3% to 17.8%) and minor quantities of arabinose (0.8% to 1.3%), galactose (0.1% to 0.3%), and uronic acids (1.3% to 2.3%) were also detected in the crude cellulose samples. Hemicelluloses are integrated into the structure of cellulose and located within and between cellulose fibrils (Duchesne et al 2001). The current data implied that alkali treatment cannot extract all the hemicelluloses and only solubilized large proportions of the hemicelluloses into the solution from the delignified material.…”

Section: Yield Intrinsic Viscosity (η) Dp and M W Of Crude And Purmentioning

confidence: 70%

“…Hemicelluloses play the role of regulator during the association of cellulose chains, and influence the pattern of aggregation of cellulose into fibril and fibril aggregates during the biogenesis a b c d of the cell wall in higher plants (Tokoh et al 1998). It has been suggested that hemicelluloses are intimately integrated into the structure of the cellulose and locate within and between the cellulose fibrils (Duchesne et al 2001). Consequently, when a large amount of the resistant hemicelluloses strongly associated to the cellulose were removed during the acetic acid treatment, the intact and smooth surface of the macrofibril changed, and it showed many terraces, steps, and kinks.…”

Section: Scanning Electron Microscopy Imagesmentioning

confidence: 99%

Acetic Acid Enhanced Purification of Crude Cellulose From Sugarcane Bagasse: Structural and Morphological Characterization

Bian¹,

Peng²,

Peng³

et al. 2012

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Crude cellulose prepared from alkali-extracted sugarcane bagasse was subjected to a rapid purification treatment with a mixture of 80% acetic acid-68% nitric acid (10/1, v/v) at 120 °C for 15 min. The yields of the preparations decreased slightly from 57.3%-58.6% in the crude cellulose preparations to 50.3%-51.9% in the purified cellulose samples. The purification treatment removed large amounts of resistant hemicelluloses strongly associated to the cellulose. XRD analysis revealed that the structure of both the crude and purified cellulose was cellulose I. Compared to the crude cellulose, a slight increase in the crystallinity index of the purified cellulose was observed by FTIR, XRD, and CP/MAS 13 C NMR analyses. In addition, SEM showed that the macrofibril surface of the crude cellulose was almost free of trenches, but many terraces, steps, and kinks formed in the preparations after the purification.

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“…Studies of the softening behavior of glucomannan and xylan suggest that xylan is more associated with lignin, while the glucomannan is more associated with cellulose (Salmén and Olsson 1998;Åkerholm and Salmén 2001;Stevanic and Salmén 2009). Duchesne et al (2001) investigated the influence of cellulose and hemicellulose on fiber ultrastructure with FE-SEM and CP/MAS 13 C-NMR in combination with spectral fitting. They determined that increasing the hemicellulose content was associated with changes in the ultrastructure of the fiber cell wall; they correlated this with differences in the mechanical properties of the pulps under consideration.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Function of Lignin and Hemicelluloses in Wood Cell Wall Revealed with Microtension of Single Wood Fiber

Zhang¹,

Wang²,

Fei³

et al. 2013

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Chinese Fir wood (Cunninghamia lanceolata (Lamb.) Hook) was subjected to extraction treatments with sodium chlorite (NaClO 2 ) for delignification, as well as with sodium hydroxide (NaOH) at different concentrations for extraction of hemicelluloses. The wood was examined using a Fourier Transform Infrared (FT-IR) spectrometer and microtension technique to track changes in the chemical and the micromechanical properties of the cell wall. The results of the microtensile tests indicated that the hemicelluloses caused more damage to the mechanical properties of the cell wall than lignin. The micromechanical properties that occurred with degradation of chemical components underlined the key role of hemicelluloses in maintaining the integrity of the cell wall.

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Untitled

Cited by 157 publications

References 19 publications

Can delignification decrease cellulose digestibility in acid pretreated corn stover?

Can delignification decrease cellulose digestibility in acid pretreated corn stover?

Acetic Acid Enhanced Purification of Crude Cellulose From Sugarcane Bagasse: Structural and Morphological Characterization

Mechanical Function of Lignin and Hemicelluloses in Wood Cell Wall Revealed with Microtension of Single Wood Fiber

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