Xylan and xylan derivatives - biopolymers with valuable properties, 1. Naturally occurring xylans structures, isolation procedures and properties

Ebringerová, Anna; Heinze, Thomas

doi:10.1002/1521-3927(20000601)21:9<542::aid-marc542>3.0.co;2-7

Cited by 781 publications

(417 citation statements)

References 114 publications

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“…However, exogenous enzyme activities against structural carbohydrates may be inhibited in the presence of LAB (Stokes, 1992;Xing et al, 2009). Xylans comprise up to 50% of the hemicelluloses in maize cobs (Ebringerová & Heinze, 2000;Vázquez et al, 2006). It was hypothesized that the nutritive value of maize cobs as a feed ingredient for pigs could be improved through degradation of xylans by commercially available xylanases and the addition of molasses and whey under anaerobic conditions.…”

Section: Introductionmentioning

confidence: 99%

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Kanengoni¹,

Nkosi²,

Chimonyo³

et al. 2016

SA J. An. Sci.

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The study was conducted to assess the effects of whey, molasses and exogenous enzymes on fermentation, aerobic stability and nutrient composition of ensiled maize cobs. Five treatments were ensiled in 1.5 L anaerobic glass jars over 32 days, namely i) control (maize cobs without additives (CON); ii) maize cobs with sugarcane molasses only (MOL); iii) MOL and whey (MOW); iv) MOW and exogenous enzyme at 0.5 g/kg maize cob mixture (ENZ1) and v) MOW and exogenous enzyme at 1 g/kg maize cob mixture (ENZ2). There was a day effect on gross energy (GE) for CON, MOL, ENZ1 and ENZ2 and none for MOW. There was a day effect in ADF for MOL, ENZ1 and ENZ2 and none for CON and MOW. There was lower dry matter (DM) on day 32 compared with day 0 for all treatments. There were treatment effects for GE, crude protein (CP), ash, ether extract, amylase-treated neutral detergent fibre and acid detergent fibre (ADF). On day 32, the neutral detergent fibre (NDF) and ADF concentrations in CON were higher than in MOL, MOW and ENZ2. At day 32, CON silage pH (4.2) was lower than the pH values of ENZ1 (4.5) and ENZ2 (4.6) silages. Acetic acid levels were higher in ENZ1 than ENZ2 silages. Ammonia nitrogen (NH 3 -N) levels averaged 25 ± 6.6 g NH 3 -N/kg total nitrogen, which is indicative of satisfactory ensiling. The MOL, ENZ1 and ENZ2 silages produced more carbon dioxide than CON and MOW silages. The addition of molasses and whey did not improve the nutritive quality of the maize cobs after ensiling. Ensiling maize cobs with molasses, whey and exogenous enzymes resulted in lower DM and fibre levels in the maize cobs, which could enhance intake and digestibility of nutrients when offered to pigs as a component of a balanced diet. Further investigations using higher concentrations of whey and molasses are warranted to improve the energy and protein composition of the maize cobs. ______________________________________________________________________________________

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Section: Introductionmentioning

confidence: 99%

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Kanengoni¹,

Nkosi²,

Chimonyo³

et al. 2016

SA J. An. Sci.

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“…1−4 Xylan-type hemicelluloses are the most abundant heteropolysaccharides in agricultural residues and there has been increasing interest in their use in food packaging and other applications. 5 Indeed, over the past few years, there have been a number of reports discussing films prepared from xylans extracted from aspen or beech, barley husks, oat spelts, wheat bran, rye grains, or corn hulls and bran. [1][2][3]6,7 Agricultural byproducts such as oat spelt or barley husk arabinoxylans have been shown to provide good oxygen and/or grease barrier films in applications where moderately high water vapor permeability is required.…”

Section: ■ Introductionmentioning

confidence: 99%

Composite Films of Arabinoxylan and Fibrous Sepiolite: Morphological, Mechanical, and Barrier Properties

Sárossy

Blomfeldt

Hedenqvist

et al. 2012

ACS Appl. Mater. Interfaces

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Hemicelluloses represent a largely unutilized resource for future bioderived films in packaging and other applications. However, improvement of film properties is needed in order to transfer this potential into reality. In this context, sepiolite, a fibrous clay, was investigated as an additive to enhance the properties of rye flour arabinoxylan. Composite films cast from arabinoxylan solutions and sepiolite suspensions in water were transparent or semitransparent at additive loadings in the 2.5−10 wt % range. Scanning electron microscopy showed that the sepiolite was well dispersed in the arabinoxylan films and sepiolite fiber aggregation was not found. FT-IR spectroscopy provided some evidence for hydrogen bonding between sepiolite and arabinoxylan. Consistent with these findings, mechanical testing showed increases in film stiffness and strength with sepiolite addition and the effect of poly(ethylene glycol) methyl ether (mPEG) plasticizer addition. Incorporation of sepiolite did not significantly influence the thermal degradation or the gas barrier properties of arabinoxylan films, which is likely a consequence of sepiolite fiber morphology. In summary, sepiolite was shown to have potential as an additive to obtain stronger hemicellulose films although other approaches, possibly in combination with the use of sepiolite, would be needed if enhanced film barrier properties are required for specific applications.

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“…Here we interrogate the ligand specificity of CBMs that recognize xylan, a ␤-1,4-linked xylose polymer, which can be decorated with glucuronosyl or 4-O-methyl-glucuronosyl residues at O2 and ␣-arabinofuranosyl or acetyl groups at O2 or O3, with the nature and extent of substitution varying between species and cell type (1,13). We have selected six CBMs, located in families 2b, 4, 6, 15, 22, and 35, listed in Table 1, which display specificity for purified xylans (6,10,(14)(15)(16)(17).…”

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confidence: 99%

“…The capacity of the xylan-binding CBMs to bind to cell walls in sections of plant materials from diverse taxonomic groups was assessed by using immunohistochemistry. In dicotyledons, low substituted xylans and MGX are abundant in the secondary cell walls of specific cell types such as xylem vessels and sclerenchyma fibers (1,13,23). The monoclonal antibody LM11, which binds to purified unsubstituted xylans and arabinoxylan, specifically recognizes secondary cell walls in all dicotyledons so far examined and shows no recognition of dicotyledon primary cell walls (23).…”

mentioning

confidence: 99%

Differential recognition of plant cell walls by microbial xylan-specific carbohydrate-binding modules

McCartney

Blake

Flint

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

129

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Glycoside hydrolases that degrade plant cell walls have complex molecular architectures in which one or more catalytic modules are appended to noncatalytic carbohydrate-binding modules (CBMs). CBMs promote binding to polysaccharides and potentiate enzymic hydrolysis. Although there are diverse sequence-based families of xylan-binding CBMs, these modules, in general, recognize both decorated and unsubstituted forms of the target polysaccharide, and thus the evolutionary rationale for this diversity is unclear. Using immunohistochemistry to interrogate the specificity of six xylan-binding CBMs for their target polysaccharides in cell walls has revealed considerable differences in the recognition of plant materials between these protein modules. Family 2b and 15 CBMs bind to xylan in secondary cell walls in a range of dicotyledon species, whereas family 4, 6, and 22 CBMs display a more limited capability to bind to secondary cell walls. A family 35 CBM, which displays more restricted ligand specificity against purified xylans than the other five protein modules, reveals a highly distinctive binding pattern to plant material including the recognition of primary cell walls of certain dicotyledons, a feature shared with CBM15. Differences in the specificity of the CBMs toward walls of wheat grain and maize coleoptiles were also evident. The variation in CBM specificity for ligands located in plant cell walls provides a biological rationale for the repertoire of structurally distinct xylanbinding CBMs present in nature, and points to the utility of these modules in probing the molecular architecture of cell walls.

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Xylan and xylan derivatives - biopolymers with valuable properties, 1. Naturally occurring xylans structures, isolation procedures and properties

Cited by 781 publications

References 114 publications

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Effects of whey, molasses and exogenous enzymes on the ensiling characteristics, nutrient composition and aerobic stability of maize cobs

Composite Films of Arabinoxylan and Fibrous Sepiolite: Morphological, Mechanical, and Barrier Properties

Differential recognition of plant cell walls by microbial xylan-specific carbohydrate-binding modules

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