Characterization of substituents in xylans from corn cobs and stover

Dongen, F.E.M. Van; Eylen, D. Van; Kabel, Mirjam A.

doi:10.1016/j.carbpol.2011.05.007

Cited by 61 publications

(39 citation statements)

References 22 publications

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“…Total lignin was 17.8 %, while their uronic acid and ash contents were 2.2 % and 1.2%, respectively. In relation to the glucose content (47.1 %), the experimental result was higher than that reported by other authors (Van Dongen et al,2011;Lili et al, 2011;Garrote et al, 2004), a fact that can be explained by the method used by each author for quantification of carbohydrates. Values of 28.0 % xilose; 5.4 % arabinose; 0.2 % mannose; and 2,9% acetyl groups, for samples determined in this study are closely comparable to those reported by them (Van Dongen et al,2011;Lili et al, 2011;Garrote et al, 2004) for similar samples.…”

Section: Quantitative Chemical Characterizationcontrasting

confidence: 83%

Extraction, Addition and Characterization of Hemicelluloses from Corn Cobs to Development of Paper Properties

Silva

Oliveira

Neto

et al. 2015

Procedia Materials Science

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Section: Quantitative Chemical Characterizationcontrasting

confidence: 83%

Extraction, Addition and Characterization of Hemicelluloses from Corn Cobs to Development of Paper Properties

Silva

Oliveira

Neto

et al. 2015

Procedia Materials Science

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“…The degree of xylan substitution by arabinose and uronic acid was also comparable to literature for corn stover (0.14 and 0.09, respectively), with the assumption that all xylose, arabinose and uronic acid were components of heteroxylan [7]. Hence, the pretreatment did not cleave arabinosyl nor glucuronosyl residues from the xylan backbone.…”

Section: Discussionsupporting

confidence: 78%

Characterisation of non-degraded oligosaccharides in enzymatically hydrolysed and fermented, dilute ammonia-pretreated corn stover for ethanol production

Jonathan

DeMartini

Thans

et al. 2017

Biotechnol Biofuels

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BackgroundCorn stover is lignocellulosic biomass that has potential to be used as raw material for bioethanol production. In the current research, dilute ammonia pretreatment was used to improve the accessibility of corn stover carbohydrates to subsequently added hydrolytic enzymes. Some carbohydrates, however, were still present after enzymatic hydrolysis and fermentation. Hence, this research was aimed to characterise the recalcitrant carbohydrates, especially the oligosaccharides that remained after hydrolysis and fermentation of dilute ammonia-pretreated corn stover (DACS).ResultsAbout 35% (w/w) of DACS carbohydrates remained after enzymatic hydrolysis and fermentation of the released monosaccharides. One-third of these recalcitrant carbohydrates were water soluble and composed of diverse oligosaccharides. By using UHPLC-MSn, more than 50 oligosaccharides were detected. Glucurono-xylooligosaccharides (UAXOS) with a degree of polymerisation (DP) less than 5 were the most abundant oligosaccharides. The (4-O-methyl) glucuronosyl substituent was mostly attached onto the terminal xylosyl residue. It was shown that the glucuronosyl substituent in some UAXOS was modified into a hexenuronosyl, a glucuronamide or a hexenuronamide residue due to the dilute ammonia pretreatment. Another group of abundant oligosaccharides comprised various xyloglucan oligosaccharides (XGOS), with a DP 5 annotated as XXG as the most pronounced. In addition, disaccharides annotated as xylosyl-glucose with different β linkages as well as larger carbohydrates were present in the fermentation slurry.ConclusionsAround one-third of the 35% (w/w) recalcitrant DACS carbohydrates remained as water-soluble saccharides. In this study, more than 50 recalcitrant oligosaccharides were detected, which mostly composed of xylosyl and/or glucosyl residues. The most pronounced oligosaccharides were UAXOS and XGOS. Hence, α-glucuronidase and α-xylosidase were suggested to be added to the enzyme mixture to degrade these oligosaccharides further, and hence the fermentation yield is potentially increased.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0803-3) contains supplementary material, which is available to authorized users.

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“…The fact that all endoxylanases were designed by nature to attack partially but significantly acetylated polysaccharides is often neglected. Acetylation of xylan is not restricted to hardwood xylan; considerable acetylation has also been reported for xylans from cereals and annual plants, including Arabidopsis thaliana [54][55][56].…”

Section: Position Of Xyn IV Among Xylanases and Its Physiological Funmentioning

confidence: 99%

Xylanase XYN IV from Trichoderma reesei showing exo‐ and endo‐xylanase activity

et al. 2012

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A minor xylanase, named XYN IV, was purified from the cellulolytic system of the fungus Trichoderma reesei Rut C30. The enzyme was discovered on the basis of its ability to attack aldotetraohexenuronic acid (HexA‐2Xyl‐4Xyl‐4Xyl, HexA3Xyl3), releasing the reducing‐end xylose residue. XYN IV exhibited catalytic properties incompatible with previously described endo‐β‐1,4‐xylanases of this fungus, XYN I, XYN II and XYN III, and the xylan‐hydrolyzing endo‐β‐1,4‐glucanase EG I. XYN IV was able to degrade several different β‐1,4‐xylans, but was inactive on β‐1,4‐mannans and β‐1,4‐glucans. It showed both exo‐and endo‐xylanase activity. Rhodymenan, a linear soluble β‐1,3‐β‐1,4‐xylan, was as the best substrate. Linear xylooligosaccharides were attacked exclusively at the first glycosidic linkage from the reducing end. The gene xyn4, encoding XYN IV, was also isolated. It showed clear homology with xylanases classified in glycoside hydrolase family 30, which also includes glucanases and mannanases. The xyn4 gene was expressed slightly when grown on xylose and xylitol, clearly on arabinose, arabitol, sophorose, xylobiose, xylan and cellulose, but not on glucose or sorbitol, resembling induction of other xylanolytic enzymes from T. reesei. A recombinant enzyme prepared in a Pichia pastoris expression system exhibited identical catalytic properties to the enzyme isolated from the T. reesei culture medium. The physiological role of this unique enzyme remains unknown, but it may involve liberation of xylose from the reducing end of branched oligosaccharides that are resistant toward β‐xylosidase and other types of endoxylanases. In terms of its catalytic properties, XYN IV differs from bacterial GH family 30 glucuronoxylanases that recognize 4‐O‐methyl‐d‐glucuronic acid (MeGlcA) substituents as substrate specificity determinants.

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Characterization of substituents in xylans from corn cobs and stover

Cited by 61 publications

References 22 publications

Extraction, Addition and Characterization of Hemicelluloses from Corn Cobs to Development of Paper Properties

Extraction, Addition and Characterization of Hemicelluloses from Corn Cobs to Development of Paper Properties

Characterisation of non-degraded oligosaccharides in enzymatically hydrolysed and fermented, dilute ammonia-pretreated corn stover for ethanol production

Xylanase XYN IV from Trichoderma reesei showing exo‐ and endo‐xylanase activity

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