Role of Acetyl Substitution in Hardwood Xylan

Gröndahl, Maria; Gatenholm, Paul

doi:10.1201/9781420030822.ch20

Cited by 16 publications

(15 citation statements)

References 8 publications

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“…Both the room temperature- and 70 °C-extracted samples were water soluble, providing further evidence of the presence of acetyl groups on the isolated xylans, as acetylation is known to provide for water solubilization of xylans (Grondahl and Gatenholm 2005; Gabrielii et al 2000). Figure 4 shows the mass spectra comparison between xylan extracted at room temperature and xylan extracted at 70 °C.…”

Section: Resultsmentioning

confidence: 83%

Efficient extraction of xylan from delignified corn stover using dimethyl sulfoxide

et al. 2013

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Xylan can be extracted from biomass using either alkali (KOH or NaOH) or dimethyl sulfoxide (DMSO); however, DMSO extraction is the only method that produces a water-soluble xylan. In this study, DMSO extraction of corn stover was studied at different temperatures with the objective of finding a faster, more efficient extraction method. The temperature and time of extraction were compared followed by a basic structural analysis to ensure that no significant structural changes occurred under different temperatures. The resulting data showed that heating to 70 °C during extraction can give a yield comparable to room temperature extraction while reducing the extraction time by ~90 %. This method of heating was shown to be the most efficient method currently available and was shown to retain the important structural characteristics of xylan extracted with DMSO at room temperature.

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Section: Resultsmentioning

confidence: 83%

Efficient extraction of xylan from delignified corn stover using dimethyl sulfoxide

et al. 2013

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“…1(b)), which benefits subsequent enzymatic hydrolysis of xylan. 43,66 The higher extraction yield and xylan purity obtained with the Hoije method could be attributed to the inclusion of the HCl pretreatment of biomass, for the removal of waxes and fats, and the separation of delignification and the xylan solubilization processes. The delignification of the xylan prior to solubilization process likely exposed the xylan to the solubilization chemicals, thereby improving extraction yield and product purity.…”

Section: Xylan Content and Extraction Efficiencymentioning

confidence: 94%

Isolation, characterization and enzymatic modification of water soluble xylans from Eucalyptus grandis wood and sugarcane bagasse

Chimphango

Zyl

Görgens

2012

J of Chemical Tech & Biotech

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BACKGROUND: There is growing interest in utilizing xylans as biodegradable polymers to replace synthetic additives, coatings and encapsulation matrices. However, techniques are required to reduce the water solubility of the xylan for such applications. The study objective was to isolate and characterize water soluble xylans from Eucalyptus grandis wood and sugarcane (Saccharum officinarum L) bagasse for subsequent precipitation in water by enzymatic modification.

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“…This suggests that the extraction procedure is specific for lignin despite the fact that the extraction yielded only 23% (i.e., X/XL). It is important to point out that the alkaline extraction of the starting material removes the native acetyl groups on the 4-O-methyl glucuronoxylan, which decreases the solubility of the polymers (Gröndahl and Gatenholm 2005).…”

Section: Characterization Of Fractionsmentioning

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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Role of Acetyl Substitution in Hardwood Xylan

Cited by 16 publications

References 8 publications

Efficient extraction of xylan from delignified corn stover using dimethyl sulfoxide

Efficient extraction of xylan from delignified corn stover using dimethyl sulfoxide

Isolation, characterization and enzymatic modification of water soluble xylans from Eucalyptus grandis wood and sugarcane bagasse

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

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