Changes in Cellulose Crystallinity During Kraft Pulping. Comparison of Infrared, X-ray Diffraction and Solid State NMR Results

Evans, R. Douglas; Newman, Roger H.; Roick, Ute C.; Suckling, Ian D.; Wallis, A. F. A.

doi:10.1515/hfsg.1995.49.6.498

Cited by 107 publications

(62 citation statements)

References 10 publications

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“…This could be due to the presence of glucomannan in the differentiated secondary cell walls. The peak at 1370 cm -1 was identified to be from crystalline cellulose (Evans et al 1995). The peak at 1730 cm -1 observed in differentiated cells could be assigned to the acetyl group from glucomannan (Carpita et al 2001).…”

Section: Resultsmentioning

confidence: 94%

Developing a model system in vitro to understand tracheary element development in Douglas-fir (Pseudostuga mensziesii)

Pillai

McDonald

Wagner

2011

Maderas, Cienc. tecnol.

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Callus cells were initiated on cambial strips obtained from 4 to 8 y old Douglas-fir (Pseudostuga menziesii) trees, cultured on solidified Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxyaceticacid (2,4-D) and benzylaminopurine (BA). The cultures could be maintained by sub-culturing on fresh medium every four weeks. When the callus cells were subsequently transferred to liquid MS medium supplemented with different phytohormones, suspension cultures could be initiated and maintained by periodic sub-culture. Approximately 65% of the callus cells cultured on liquid MS medium supplemented with 2,4-D, when maintained for 6-7 weeks without sub-culture, differentiated to tracheary element (TE) like cells. The formation of TE like cells was confirmed histochemically by staining with phloroglucinol-HCl. Secondary thickening of the cell walls were confirmed by polarized light microscopy, which showed strong birefringence of the cell wall due the presence of crystalline cellulose. The presence of lignin was determined by pyrolysis-GC-MS and FTIR spectroscopy. The lignin content in differentiated cell wall samples was quantified at 21% by the lignothioglycolic acid assay. Analysis of monosaccharide composition of cell wall samples after acid hydrolysis showed that the percentage of glucose, xylose and mannose had increased in the differentiated cell walls. These increases correspond to the formation of cellulose, glucomannan and xylan, primarily associated with secondary cell walls.

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Section: Resultsmentioning

confidence: 94%

Developing a model system in vitro to understand tracheary element development in Douglas-fir (Pseudostuga mensziesii)

Pillai

McDonald

Wagner

2011

Maderas, Cienc. tecnol.

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“…Evans et al 29 observed an increase in the cellulose CrI as kraft pulping proceeded due to preferential removal of the less ordered carbohydrates. A similar result was reported in other alkaline pretreatment (lime) where the CrI increased slightly 30 .…”

Section: Resultsmentioning

confidence: 99%

“…The saccharification yields are just slightly higher for the pulps pretreated at 165°C than those pretreated at 155°C, for both AA concentrations (Table 2). Cellulose enzymatic hydrolysis is a complex process and a structural characteristic may not by itself adequately explain differences in the hydrolysis 29 . Digestibility of lignocellulosic biomass is affected by the structural properties of cell-wall components such as lignin/hemicellulose association, cellulose crystallinity index CrI and polymerization degree DP The results indicate that all the kraft pretreatment conditions employed in this study effectively improve the enzymatic digestibility of material.…”

Section: Enzymatic Hydrolysable Carbohydrates In the Pretreated Materialsmentioning

confidence: 99%

Kraft Pulping of Eucalyptus Globulus as a Pretreatment for Bioethanol Production by Simultaneous Saccharification and Fermentation

Monrroy

García²,

Mendonça³

et al. 2012

J. Chil. Chem. Soc.

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The kraft pulping process was evaluated in this study as a pretreatment of Eucalyptus globulus for bioethanol production. Wood chips were pretreated under different pulping conditions (155°C and 165°C; 15 and 20 % alkali active AA, 15-60 min). A total of 12 pulps were obtained, with pulp yields ranging from 49 to 57%. Glucan remained in pulps were from 77% and 90%, while 50% of the hemicelluloses were solubilized. Lignin removal increased with increased severity of cooking (high active alkali charge, pretreatment time and temperature) reaching delignification over 78%. The enzymatic hydrolysis of kraft pulps with cellulase presented a rapid glucan conversion rate to glucose with values over 90%. Lignin, hemicellulose removal, as well as, cellulose polymerization degree showed an effect on the increment of enzymatic hydrolysis. The degree of crystallinity increased slightly between 1-5%, having no effect on the enzymatic hydrolysis. The simultaneous saccharification and fermentation was performed (SFS) at 10% substrate consistency with a production at 30-38 g ethanol/L. The maximum amount of ethanol that could be produced from E. globulus is 258 g ethanol/kg wood, assuming total glucose conversion into ethanol. The amounts of ethanol obtained from the different pulps varied between 168-202 g ethanol/kg wood. The ethanol yields obtained from kraft pulps varied between 65 and 78% (wood basis). The maximum ethanol yield was 78% at 155°C, 15% AA and 60 min reaction, while the yield was 74% at 165°C, 15% AA and 30 min of reaction time. Results showed that an efficient enzymatic hydrolysis at low enzyme loads could be obtained from kraft pulps employing less severe conditions than those used to produce bleachable -grade pulps.

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“…Therefore, NMR crystallinity index reflects the amount of total cellulose within crystallite interiors, rather than the total amount of crystalline cellulose. Consequently, the NMR crystallinity depends on the size of crystallites (Evans et al 1995). WAXS crystallinity presents the mass fraction of crystalline material in the sample, but if the crystallite size is small, the separation of the amorphous background becomes difficult lowering the accuracy of the crystallinity value.…”

Section: Discussionmentioning

confidence: 99%

Studies of crystallinity of Scots pine and Norway spruce cellulose

Andersson

Wikberg

Pesonen

et al. 2004

Trees - Structure and Function

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The variation in the mass fraction of crystalline cellulose (crystallinity of wood), the intrinsic crystallinity of cellulose, and the thickness of cellulose crystallites in early wood of Norway spruce [Picea abies (L.) Karst.], and Scots pine (Pinus sylvestris L.) grown in Finland were studied using wide angle X-ray scattering and nuclear magnetic resonance spectroscopy. The mass fraction of crystalline cellulose in wood increased slightly with the distance from the pith and was about 30€4% in mature wood of both species. The crystallinity of cellulose and the thickness of cellulose crystallites were almost constant for both species. The crystallinity of cellulose was 52€3% for both species and the average thickness of the cellulose crystallites was 32€1 and 31€1 for Norway spruce and Scots pine, respectively. The mass fraction of cellulose in wood, calculated from the crystallinity values, increased with the distance from the pith for both species.

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Changes in Cellulose Crystallinity During Kraft Pulping. Comparison of Infrared, X-ray Diffraction and Solid State NMR Results

Cited by 107 publications

References 10 publications

Developing a model system in vitro to understand tracheary element development in Douglas-fir (Pseudostuga mensziesii)

Developing a model system in vitro to understand tracheary element development in Douglas-fir (Pseudostuga mensziesii)

Kraft Pulping of Eucalyptus Globulus as a Pretreatment for Bioethanol Production by Simultaneous Saccharification and Fermentation

Studies of crystallinity of Scots pine and Norway spruce cellulose

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