Effects of Delignification on Crystalline Cellulose in Lignocellulose Biomass Characterized by Vibrational Sum Frequency Generation Spectroscopy and X-ray Diffraction

Kafle, Kabindra; Lee, Christopher; Shin, Heenae; Zoppe, Justin Orazio; Johnson, David K.; Kim, Seong H.; Park, Sunkyu

doi:10.1007/s12155-015-9627-9

Cited by 37 publications

(25 citation statements)

References 47 publications

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“…The increase in NaOH concentration boosted the crystal form transformation of cellulose was boosted, and subsequently promoted the separation of the remaining lignin and cellulose in the plant cell wall through enzymatic hydrolysis1415. In addition, although the relative content of cellulose in the preswelled samples increased after alkaline pretreatment, its absolute quality was decreasing, which was caused by the peeling reaction of terminal glucose in alkaline conditions1617.…”

Section: Resultsmentioning

confidence: 99%

Effect of alkaline preswelling on the structure of lignins from Eucalyptus

Chen

Yang

Zhang

et al. 2017

Sci Rep

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A clear elucidation of structural feature of whole lignin in plant cell wall is of great importance for understanding lignin biosynthesis mechanism and developing lignin based chemicals or materials under the current biorefinery scenario. Swollen residual enzyme lignin (SREL) has been identified as an ideal representative for native lignin in the plant walls. To investigate the influence of preswelling conditions on the structural features, the SREL obtained through preswelling the ball-milled Eucalyptus wood powder in 2, 4 and 8% NaOH solutions and subsequent in-situ enzymatic hydrolysis were thoroughly characterized. A cellulolytic enzyme lignin (CEL) was also prepared as a comparison. The quantitative NMR analyses indicated that the relative contents of β-O-4′ linkages in SRELs were higher than that in CEL. The lignin structure tended to undergo more destruction with the elevated NaOH concentration. A relatively low NaOH concentration (2% in this study), which could be applied to effectively remove hemicelluloses and transform cellulose structure from cellulose I to cellulose II, was competent to prepare SREL as an ideal representative for the protolignin. An optimization of SREL preparation was essential for a better understanding of the whole protolignin.

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Section: Resultsmentioning

confidence: 99%

Effect of alkaline preswelling on the structure of lignins from Eucalyptus

Chen

Yang

Zhang

et al. 2017

Sci Rep

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“…Treatments with alkali effectively dissolve hemicellulose, but other processes are necessary to hydrolyze lignin. Lignocellulose delignification via sodium chlorite (NaClO 2 ) bleaching has been traditionally used, but this process has been replaced with more environmentally friendly methods such as thermochemical reactions based on oxygen [27] and hydrogen peroxide (H 2 O 2 ) [28]. Therefore, new methodologies are welcome to obtain nanocellulose via more environmentally friendly processes, making the product a more attractive material for commercial applications.…”

Section: Introductionmentioning

confidence: 99%

Using Commercial Enzymes to Produce Cellulose Nanofibers from Soybean Straw

Martelli‐Tosi¹,

Torricillas²,

Martins

et al. 2016

Journal of Nanomaterials

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This study used commercial enzymes to isolate cellulose nanofibrils (CN) and produce sugars from chemically pretreated soybean straw (SS) (stem, leaves, and pods) by alkali (NaOH 5 or 17.5% v/v at 90°C for 1 h or at 30°C for 15 h) and bleaching (NaClO23.3% or H2O24%) pretreatments. Depending on the pretreatment applied to the soybean straw, the yield of CN varied from 6.3 to 7.5 g of CN/100 g of SS regardless of the concentration of the alkaline solution (5 or 17.5%). The CN had diameter of 15 nm, measured over 300 nm in length, and had high electrical stability (zeta potentials ranged from −20.8 to −24.5). Given the XRD patterns, the crystallinity index (CrI) of CN ranged from 45 to 68%, depending on the chemical pretreatment the starting material was submitted to. CN obtained from SS treated with NaOH 17.5% and H2O2(CrI = 45%) displayed better thermal stability probably because a lignin-cellulose complex emerged. The soluble fraction obtained in the first step of CN production contained a large amount of reducing sugars (11.2 to 30.4 g/100 g of SS). SS seems to be a new promising industrial source to produce CN via enzymatic-mechanical treatment, leading to large amounts of reducing sugars for use in bioenergy production.

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“…In order to improve the accessibility of enzymes to the cellulose substrate, lignocellulose biomass is typically pretreated via various methods such as dilute acid, autohydrolysis, alkaline, or steam explosion pretreatment 9 10 . However, aggregation of cellulose microfibrils could occur after removal of lignin and matrix polymers during pretreatments 11 12 13 . The aggregation of cellulose microfibrils might negatively affect the surface accessibility 14 15 .…”

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confidence: 99%

Progressive structural changes of Avicel, bleached softwood and bacterial cellulose during enzymatic hydrolysis

Kafle

Shin

Lee

et al. 2015

Sci Rep

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A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellulose—to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlate with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. It was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component.

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Effects of Delignification on Crystalline Cellulose in Lignocellulose Biomass Characterized by Vibrational Sum Frequency Generation Spectroscopy and X-ray Diffraction

Cited by 37 publications

References 47 publications

Effect of alkaline preswelling on the structure of lignins from Eucalyptus

Effect of alkaline preswelling on the structure of lignins from Eucalyptus

Using Commercial Enzymes to Produce Cellulose Nanofibers from Soybean Straw

Progressive structural changes of Avicel, bleached softwood and bacterial cellulose during enzymatic hydrolysis

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