Characterization and molecular weight distribution of carbohydrates isolated from the autohydrolysis extract of mixed southern hardwoods

Tunç, Mehmet; Heiningen, A. R. P. Van

doi:10.1016/j.carbpol.2010.07.015

Cited by 51 publications

(22 citation statements)

References 19 publications

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“…For this reason, the increased extraction yield with increasing EtOH temperature (from 150 o C to 160 o C) of water-pretreated SHM was probably due to the increased dissolution of carbohydrates in the EtOH extract at higher temperatures. These carbohydrates are presumably in the form of lignin-carbohydrate complexes (LCCs) (Tunc et al 2010, Tunc andvan Heiningen 2011), because pure oligomeric saccharides are rather insoluble in ethanol-water. The severity factor (Overend et al 1987) of the present autohydrolysis of 160 °C for 90 min is 3.72.…”

Section: Optimum Conditions For Etoh Extraction Of Two-stage Wood Framentioning

confidence: 99%

“…Therefore, the present finding that no precipitates are seen in the FA extract or following EtOH extract is highly significant. The amount of xylan dissolved in the EtOH extract was higher than that dissolved during FA extraction up to an FA temperature of 150 o C. The likely explanation is that xylan in the EtOH extract was removed with lignin in the form of lignin carbohydrate complexes (LCCs) (Tunc et al 2010, Tunc andvan Heiningen 2011). At higher FA extraction temperatures, the chemical bond between xylan and lignin was progressively broken, which led to more xylan in the FA extract and correspondingly less in the EtOH extract.…”

Section: Effect Of Formic Acid Extraction Temperaturementioning

confidence: 99%

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Two-Stage Fractionation of Hardwoods

Tunç¹,

Chheda²,

Heide³

et al. 2013

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A two-stage lignocellulosic biomass fractionation process consisting of a formic-or acetic acid-reinforced wood autohydrolysis step followed by an ethanol-water treatment was applied to a mixture of Southern hardwood chips. The wood products in the hydrolysate were mostly monomeric xylose, other monomeric sugars, polymeric hemicelluloses, acetic acid, and a relatively small amount of lignin. The second step mostly dissolves sulfur-free lignin, while the fibrous residue consists mainly of cellulose fibers, which may be used for liquid fuels or pulp production. The yield composition, and quality of these products were determined as a function of treatment conditions, with the aim to develop an economic and robust biorefinery fractionation technology.

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Section: Optimum Conditions For Etoh Extraction Of Two-stage Wood Framentioning

confidence: 99%

Section: Effect Of Formic Acid Extraction Temperaturementioning

confidence: 99%

Two-Stage Fractionation of Hardwoods

Tunç¹,

Chheda²,

Heide³

et al. 2013

BioResources

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“…It is generally accepted that free lignin in precipitates hemicelluloses, which are extracted with solvent, such as dioxane, at less than 1.0% (w/w) based on dry precipitates. Tunk and van Heiningen (2011) showed that the free lignin content increased from 0.2% (w/w) to 0.8% (w/w) in the precipitates when temperature increased from 130 °C to 170 °C. During the first 40 min hydrolysis at 160 °C, all lignin-free xylan is removed, and from then on all xylan dissolved is in the form of lignin-carbohydrate complexes (Chen et al 2010).…”

Section: Component Analysis and Characterization Of Precipitatesmentioning

confidence: 99%

Comparative Study on the Yield and Characterization of Hemicelluloses Isolated with Hydrothermal Extract and Catalyzed by Acetic Acid from Acacia Wood

et al. 2017

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aTo utilize hemicelluloses from biomass as a feedstock to produce various value-added products, the soluble hemicelluloses must be isolated from the liquid phase with a high yield and purity. In this study, acacia wood was extracted by hydrothermal treatment, catalyzed by acetic acid at 170 °C for different lengths of time, and then precipitated after concentration and mixing with ethanol. Acetic acid led to faster hydrolysis of hemicelluloses, a process that was confirmed by a larger amount of total saccharides than the controlled results. A yield of more than 90% oligosaccharides was achieved in the hydrolysate with 1% (w/w) acetic acid. The maximum precipitate yield obtained was reduced, but a faster increase was observed in the first 30 min at 170 °C depending on the utilization of acetic acid. Analysis of 13 C nuclear magnetic resonance ( 13 C NMR) confirmed that the side chains, such as arabinose linked on the xylan chain, were severely broken down, and more dissolved hemicelluloses bonded with lignin (LCC) were present in the precipitates with 1% (w/w) acetic acid. Based on gel permeation chromatography (GPC), a molecular weight of not less than 1900 is suggested when ethanol is used to precipitate the oligosaccharides from hydrolysate. Keywords INTRODUCTIONThe chemical pulping industry is one of the largest manufacturers of lignocellulosic material, from which high strength and whiteness fibers are produced to make various grades of end-use papers. However, due to the increased capacity of the pulp and paper industry, the profitability of this industry is decreasing. Biorefining has been proposed to reshape the pulping industry by utilizing biomass resources more effectively and producing a variety of products (Vila et al. 2011;Liu et al. 2015). In kraft pulping, about 20% of biomass, mainly hemicelluloses, are dissolved in the black liquor along with lignin and then burned in the recovery cycle to produce energy for the process. However, the heating value of hemicelluloses is half that of lignin (13.6 MJ/kg) (Tunc and van Heiningen 2008). Therefore, instead of burning the hemicelluloses with black liquor, hemicellulose extraction prior to chemical pulping has been widely discussed as a practical approach in the implementation of a pulp mill-based biorefinery. There is great potential for the conversion of hemicelluloses derivatives into high-value added products such as fuels, films, health products, and polymers (Vila et al. 2011).Hydrothermal pretreatment (hot water treatment or autohydrolysis) is widely used to extract hemicelluloses from biomass for producing fermentable sugars and PEER-REVIEWED ARTICLE bioresources.com Shi et al. (2017). "Hemicelluloses from Acacia," BioResources 12(3), 6094-6108. 6095oligosaccharides (Ertas et al. 2014;Batalha et al. 2015;Cuevas et al. 2015). This method is a simple, low-cost, and attractive technology for extracting lignocelluloses in the kraft pulping (Deb et al. 2016), soda, soda-anthraquinone, and soda ethylenediamine processes for producing dissolving pulp (...

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“…That soluble fraction is composed from a variety of non-precipitated carbohydrates and especially carbohydrate degradation products such as monocarboxylic and dicarboxylic hydroxy acids, together with formic and acetic acids, and lignin fragments. Also, during the alkaline treatment, the carbohydrate components in wood are subjected to degradation through the hydrolysis of acetyl groups, the dissolution of low weight carbohydrates, peeling reaction, and alkaline hydrolysis (Tunc and van Heiningen 2011;Sjöström 1993).…”

Section: Characterization Of Ethanol Precipitated Materials (Epm)mentioning

confidence: 99%

Ethanol Precipitation of Hetero-Polysaccharide Material from Hardwood by Alkaline Extraction Prior to the Kraft Cooking Process

et al. 2013

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aHemicellulose material is an abundant and relatively under-utilized hetero-polysaccharide material present in lignocellulosic materials. In this study, an alkaline treatment was applied to sweetgum and Eucalyptus globulus chips to extract hemicelluloses prior to kraft pulping to subsequently evaluate the final product and process. An alkaline extraction (10 and 50% NaOH by weight on wood) for 60 min at 100 °C followed by precipitation in ethanol recovered 4.3% of the biomass as a predominantly xylan material (sweetgum 50% NaOH) with an average degree of polymerization around 250 and functional groups similar to a commercial xylan (sweetgum 10% NaOH). This process in comparison to autohydrolysis (water extraction at 100 °C) produced a much higher molecular weight and more pure hemicellullose. The results obtained indicate a promising combination between the effective extraction of hemicellulose from wood and a distillation process that recovers the ethanol, which may be an attractive alternative to recover liquor and ethanol after hemicellulose precipitation. Hemicellulose from sweetgum showed more thermal stability with high molecular weight compared to the hemicellulose extracted from Eucalyptus globulus. An attractive alternative looks to be to recover liquor and ethanol after hemicellulose precipitation.

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Characterization and molecular weight distribution of carbohydrates isolated from the autohydrolysis extract of mixed southern hardwoods

Cited by 51 publications

References 19 publications

Two-Stage Fractionation of Hardwoods

Two-Stage Fractionation of Hardwoods

Comparative Study on the Yield and Characterization of Hemicelluloses Isolated with Hydrothermal Extract and Catalyzed by Acetic Acid from Acacia Wood

Ethanol Precipitation of Hetero-Polysaccharide Material from Hardwood by Alkaline Extraction Prior to the Kraft Cooking Process

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