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Arthur J Ragauskas - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Cellulose Structure of Populus plants modified in candidate Cellulose biosynthesis genes
Biomass and Bioenergy, 2016Co-Authors: Garima Bali, Ratayakorn Khunsupat, Hannah Akinosho, Raja S. Payyavula, Reichel Samuel, Gerald A. Tuskan, Udaya C. Kalluri, Arthur J RagauskasAbstract:Here, the recalcitrant nature of lignocellulosic biomass is a combined effect of several factors such as high crystallinity and high degree of polymerization of Cellulose, lignin content and Structure, and the available surface area for enzymatic degradation (i.e., accessibility). Genetic improvement of feedstock cell wall properties is a path to reducing recalcitrance of lignocellulosic biomass and improving conversion to various biofuels. An advanced understanding of the Cellulose biosynthesis pathway is essential to precisely modify Cellulose properties of plant cell walls. Here we report on the impact of modified expression of candidate Cellulose biosynthesis pathway genes on the ultra-Structure of Cellulose, a key carbohydrate polymer of Populus cell wall using advanced nuclear magnetic resonance approaches. Noteworthy changes were observed in the cell wall characteristics of downregulated KORRIGAN 1 (KOR) and KOR 2 transgenic plants in comparison to the wild-type control. It was observed that all of the transgenic lines showed variation in Cellulose ultraStructure, increase in Cellulose crystallinity and decrease in the Cellulose degree of polymerization. Additionally, the properties of Cellulose allomorph abundance and accessibility were found to be variable. Application of such Cellulose characterization techniques beyond the traditional measurement of Cellulose abundance to comprehensive studies of Cellulose properties in largermore » transgenic and naturally variable populations is expected to provide deeper insights into the complex nature of lignocellulosic material, which can significantly contribute to the development of precisely tailored plants for enhanced biofuels production.« less
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The effect of alkaline pretreatment methods on Cellulose Structure and accessibility.
ChemSusChem, 2014Co-Authors: Garima Bali, Xianzhi Meng, Jacob I. Deneff, Qining Sun, Arthur J RagauskasAbstract:The effects of different alkaline pretreatments on Cellulose structural features and accessibility are compared and correlated with the enzymatic hydrolysis of Populus. The pretreatments are shown to modify polysaccharides and lignin content to enhance the accessibility for cellulase enzymes. The highest increase in the Cellulose accessibility was observed in dilute sodium hydroxide, followed by methods using ammonia soaking and lime (Ca(OH)2 ). The biggest increase of Cellulose accessibility occurs during the first 10 min of pretreatment, with further increases at a slower rate as severity increases. Low temperature ammonia soaking at longer residence times dissolved a major portion of hemiCellulose and exhibited higher Cellulose accessibility than high temperature soaking. Moreover, the most significant reduction of degree of polymerization (DP) occurred for dilute sodium hydroxide (NaOH) and ammonia pretreated Populus samples. The study thus identifies important Cellulose structural features and relevant parameters related to biomass recalcitrance.
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Comparison of laboratory delignification methods, their selectivity, and impacts on physiochemical characteristics of cellulosic biomass.
Bioresource technology, 2012Co-Authors: Rajeev Kumar, Arthur J Ragauskas, Christopher A. Hubbell, Charles E. WymanAbstract:Two established delignification methods employing sodium chlorite-acetic acid (SC/AA) and peracetic acid (PAA) are often used, and are reportedly highly selective. However, these reports are mostly for highly recalcitrant and unpretreated softwoods and hardwoods species, and information for less recalcitrant lignocellulosic feedstocks and pretreated biomass is scarce. Furthermore, the effects on Cellulose Structure are not documented. Thus, in this study, delignification kinetics and selectivity were evaluated when SC/AA and PAA were applied to untreated switchgrass, poplar, corn stover, and pine sawdust; poplar subjected to AFEX, controlled pH, lime, and SO(2) pretreatments; and the Cellulose model compounds. Both methods proved effective in removing >90% lignin, but selectivity for lignin and carbohydrates removal was substrate and pretreatment dependent. For untreated biomass, PAA was more selective in removing lignin than SC/AA; however, both methods were less selective for pretreated solids. Cellulose characterizations revealed that PAA had less pronounced impacts on Cellulose Structure.
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effects of organosolv pretreatment and enzymatic hydrolysis on Cellulose Structure and crystallinity in loblolly pine
Carbohydrate Research, 2010Co-Authors: Poulomi Sannigrahi, Stephen J Miller, Arthur J RagauskasAbstract:Abstract Ethanol organosolv pretreatment was performed on Loblolly pine to enhance the efficiency of enzymatic hydrolysis of Cellulose to glucose. Solid-state 13C NMR spectroscopy coupled with line shape analysis was used to determine the Structure and crystallinity of Cellulose isolated from pretreated and enzyme-hydrolyzed Loblolly pine. The results indicate reduced crystallinity of the Cellulose following the organosolv pretreatment, which renders the substrate easily hydrolyzable by cellulase. The degree of crystallinity increases and the relative proportion of para-crystalline and amorphous Cellulose decreases after enzymatic hydrolysis, indicating preferential hydrolysis of these regions by cellulase. The structural and compositional changes in this material resulting from the organosolv pretreatment and cellulase enzyme hydrolysis of the pretreated wood were studied with solid-state CP/MAS 13C NMR spectroscopy. NMR spectra of the solid material before and after the treatments show that hemiCelluloses and lignin are degraded during the organosolv pretreatment.
Pekka Saranpaa - One of the best experts on this subject based on the ideXlab platform.
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Cellulose Structure and lignin distribution in normal and compression wood of the Maidenhair tree（Ginkgo biloba L.）
Journal of Integrative Plant Biology, 2015Co-Authors: Seppo Andersson, Raili Pönni, Tuomas Hanninen, Marko Mononen, Ritva Serimaa, Yurong Wang, Pekka SaranpaaAbstract:We studied in detail the mean microfibril angle and the width of Cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree (Ginkgo biloba L.). The orientation of Cellulose microfibrils with respect to the cell axis and the width and length of Cellulose crystallites were determined using X-ray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean microfibril angle, varying between 19° and 39° in the S2 layer, and the average width of Cellulose crystallites was 3.1–3.2 nm. Mild compression wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2L layer confirmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The microfibril angle remained large over the 14 annual rings. The entire stem disc, with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the Cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.
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Cellulose Structure and lignin distribution in normal and compression wood of the maidenhair tree ginkgo biloba l
Journal of Integrative Plant Biology, 2015Co-Authors: Seppo Andersson, Raili Pönni, Tuomas Hanninen, Marko Mononen, Ritva Serimaa, Yurong Wang, Pekka SaranpaaAbstract:We studied in detail the mean microfibril angle and the width of Cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree (Ginkgo biloba L.). The orientation of Cellulose microfibrils with respect to the cell axis and the width and length of Cellulose crystallites were determined using X-ray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean microfibril angle, varying between 19° and 39° in the S2 layer, and the average width of Cellulose crystallites was 3.1–3.2 nm. Mild compression wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2L layer confirmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The microfibril angle remained large over the 14 annual rings. The entire stem disc, with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the Cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.
Seong H Kim - One of the best experts on this subject based on the ideXlab platform.
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Does Cellulose II exist in native alga cell walls? Cellulose Structure of Derbesia cell walls studied with SFG, IR and XRD
Cellulose, 2015Co-Authors: Yong Bum Park, Christopher M Lee, Kabindra Kafle, Daniel J Cosgrove, Seong H KimAbstract:In nature, algae produce Cellulose I where all glucan chains are aligned parallel. However, the presence of Cellulose II with anti-parallel glucan chains has been reported for certain Derbesia (Chlorophyceae algae) cell walls; if this is true, it would mean a new biological process for synthesizing Cellulose that has not yet been recognized. To answer this question, we examined Cellulose Structure in Derbesia cell walls, intact as well as treated with Cellulose isolation procedures, using sum-frequency-generation spectroscopy, infrared (IR) spectroscopy and X-ray diffraction (XRD). Derbesia walls contain large amounts of mannan and small amounts of crystalline Cellulose. Evidence for Cellulose II in the intact cell walls was not found, whereas Cellulose II in the trifluoroacetic acid (TFA) treated cell wall samples were detected by IR and XRD. A control experiment conducted with ball-milled Avicel Cellulose samples showed that Cellulose II Structure could be formed as a result of TFA treatment and drying of amorphous Cellulose. These data suggest that the Cellulose II Structure detected in the TFA-treated Derbesia gametophyte wall samples is most likely due to reorganization of amorphous Cellulose during the sample preparation. Our results contradict the previous report of Cellulose II in native alga cell walls. Even if the crystalline Cellulose II exists in intact Derbesia gametophyte cell walls, its amount would be very small (below the detection limit) and thus biologically insignificant.
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effects of plant cell wall matrix polysaccharides on bacterial Cellulose Structure studied with vibrational sum frequency generation spectroscopy and x ray diffraction
Biomacromolecules, 2014Co-Authors: Yong Bum Park, Christopher M Lee, Kabindra Kafle, Sunkyu Park, Daniel J Cosgrove, Seong H KimAbstract:The crystallinity, allomorph content, and mesoscale ordering of Cellulose produced by Gluconacetobacter xylinus cultured with different plant cell wall matrix polysaccharides were studied with vibrational sum frequency generation (SFG) spectroscopy and X-ray diffraction (XRD). Crystallinity and ordering were assessed as the intensity of SFG signals in the CH/CH2 stretch vibration region (and confirmed by XRD), while Iα content was assessed by the relative intensity of the OH stretch vibration at 3240 cm–1. A key finding is that the presence of xyloglucan in the culture medium greatly reduced Iα allomorph content but with a relatively small effect on Cellulose crystallinity, whereas xylan resulted in a larger decrease in crystallinity with a relatively small decrease in the Iα fraction. Arabinoxylan and various pectins had much weaker effects on Cellulose Structure as assessed by SFG and XRD. Homogalacturonan with calcium ion reduced the SFG signal, evidently by changing the ordering of Cellulose microfibr...
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Characterization of crystalline Cellulose in biomass: Basic principles, applications, and limitations of XRD, NMR, IR, Raman, and SFG
Korean Journal of Chemical Engineering, 2013Co-Authors: Seong H Kim, Christopher M Lee, Kabindra KafleAbstract:Cellulose is among the most important and abundant biopolymers in biosphere. It is the main structural component of a vast number of plants that carries vital functions for plant growth. Cellulose-based materials have been used in a variety of human activities ranging from papers and fabrics to engineering applications including production of biofuels. However, our understanding of the Cellulose Structure in its native form is quite limited because the current experimental methods often require separation or purification processes and provide only partial information of the Cellulose Structure. This paper aims at providing a brief background of the Cellulose Structure and reviewing the basic principles, capabilities and limitations of the Cellulose characterization methods that are widely used by engineers dealing with biomass. The analytical techniques covered in this paper include x-ray diffraction, nuclear magnetic resonance, and vibrational spectroscopy (infrared, Raman, and sum-frequency-generation). The scope of the paper is restricted to the application of these techniques to the structural analysis of Cellulose.
Seppo Andersson - One of the best experts on this subject based on the ideXlab platform.
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Cellulose Structure and lignin distribution in normal and compression wood of the Maidenhair tree（Ginkgo biloba L.）
Journal of Integrative Plant Biology, 2015Co-Authors: Seppo Andersson, Raili Pönni, Tuomas Hanninen, Marko Mononen, Ritva Serimaa, Yurong Wang, Pekka SaranpaaAbstract:We studied in detail the mean microfibril angle and the width of Cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree (Ginkgo biloba L.). The orientation of Cellulose microfibrils with respect to the cell axis and the width and length of Cellulose crystallites were determined using X-ray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean microfibril angle, varying between 19° and 39° in the S2 layer, and the average width of Cellulose crystallites was 3.1–3.2 nm. Mild compression wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2L layer confirmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The microfibril angle remained large over the 14 annual rings. The entire stem disc, with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the Cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.
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Cellulose Structure and lignin distribution in normal and compression wood of the maidenhair tree ginkgo biloba l
Journal of Integrative Plant Biology, 2015Co-Authors: Seppo Andersson, Raili Pönni, Tuomas Hanninen, Marko Mononen, Ritva Serimaa, Yurong Wang, Pekka SaranpaaAbstract:We studied in detail the mean microfibril angle and the width of Cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree (Ginkgo biloba L.). The orientation of Cellulose microfibrils with respect to the cell axis and the width and length of Cellulose crystallites were determined using X-ray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean microfibril angle, varying between 19° and 39° in the S2 layer, and the average width of Cellulose crystallites was 3.1–3.2 nm. Mild compression wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2L layer confirmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The microfibril angle remained large over the 14 annual rings. The entire stem disc, with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the Cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.
Lars Berglund - One of the best experts on this subject based on the ideXlab platform.
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Preserving Cellulose Structure: Delignified Wood Fibers for Paper Structures of High Strength and Transparency.
Biomacromolecules, 2018Co-Authors: Xuan Yang, Fredrik Berthold, Lars BerglundAbstract:To expand the use of renewable materials, paper products with superior mechanical and optical properties are needed. Although beating, bleaching, and additives are known to improve industrially produced Kraft pulp papers, properties are limited by the quality of the fibers. While the use of nanoCellulose has been shown to significantly increase paper properties, the current cost associated with their production has limited their industrial relevance. Here, using a simple mild peracetic acid (PAA) delignification process on spruce, we produce hemiCellulose-rich holoCellulose fibers (28.8 wt %) with high intrinsic strength (1200 MPa for fibers with microfibrillar angle smaller than 10°). We show that PAA treatment causes less Cellulose/hemiCellulose degradation and better preserves Cellulose nanoStructure in comparison to conventional Kraft pulping. High-density holoCellulose papers with superior mechanical properties (Young’s modulus of 18 GPa and ultimate strength of 195 MPa) are manufactured using a wate...