Effect of autohydrolysis of Eucalyptus globulus wood on lignin structure. Part 1: Comparison of different lignin fractions formed during water prehydrolysis

Holzforschung ◽  
2008 ◽  
Vol 62 (6) ◽  
Author(s):  
Moritz Leschinsky ◽  
Gerhard Zuckerstätter ◽  
Hedda K. Weber ◽  
Rudolf Patt ◽  
Herbert Sixta
Keyword(s):  
Nmr Spectroscopy ◽  
Eucalyptus Globulus ◽  
Lignin Degradation ◽  
Degradation Products ◽  
Chemical Properties ◽  
Size Exclusion ◽  
Strong Increase ◽  
Hydroxyl Groups ◽  
Aryl Ether ◽  
Wood Residue

Abstract The effect of autohydrolysis of Eucalyptus globulus wood was studied with regard to conditions applied in a prehydrolysis-kraft process on the physico-chemical properties of lignin obtained in both the wood residue and hydrolysate. As a reference, milled wood lignin (MWL) was isolated from native wood and compared to three lignin fractions formed during prehydrolysis: 1) lignin from the wood residue isolated as MWL, 2) lignin precipitated from the prehydrolysate during cooling and separated by centrifugation, and 3) lignin degradation products soluble in the prehydrolysate extracted with ethylacetate. All lignin fractions were subjected to Fourier transform infrared (FTIR) spectroscopy, methoxy group determination, elemental analysis, size exclusion chromatography and quantitative nuclear magnetic resonance (NMR) spectroscopy. The results indicate that extensive lignin degradation occurs during prehydrolysis through homolytic cleavage of the aryl-ether bonds resulting in a substantial molecular weight loss of the residual lignin in the treated wood and in the lignin fractions isolated from the prehydrolysate. The aryl-ether cleavage is coupled with a strong increase in phenolic hydroxyl groups and a decrease in aliphatic hydroxyl groups. Indication for condensation reactions were found by NMR spectroscopy.

Isolation and characterization of lignins from Eucalyptus grandis Hill ex Maiden and Eucalyptus globulus Labill. by enzymatic mild acidolysis (EMAL)

Holzforschung ◽  
2008 ◽  
Vol 62 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Anderson Guerra ◽  
Lucian A. Lucia ◽  
Dimitris S. Argyropoulos
Keyword(s):  
Eucalyptus Globulus ◽  
Eucalyptus Grandis ◽  
Raw Material ◽  
Size Exclusion ◽  
Hydroxyl Groups ◽  
Aryl Ether ◽  
Isolation And Characterization ◽  
White Fir ◽  
Exclusion Chromatography

Abstract Despite the growing importance of Eucalyptus wood as raw material for pulp and paper, there is a lack of knowledge on the chemistry of their macromolecular components. The present paper addresses this issue by applying the recently developed protocol for isolating enzymatic mild acidolysis lignins (EMAL) from Eucalyptus grandis, Eucalyptus globulus and the softwood species Douglas fir and white fir, which were used for comparative purposes. The structures of EMALs were investigated by quantitative 31P NMR, DFRC/31P NMR (derivatization followed by reductive cleavage followed by quantitative 31P NMR) and size exclusion chromatography (SEC). Overall, the yields of EMALs isolated from Eucalyptus were higher than those from the softwoods examined. Lignin from E. globulus was found to contain higher contents of arylglycerol-β-aryl ether structures, free phenolic hydroxyl groups and syringyl-type units than lignin from E. grandis. New insights provided by the DFRC/31P NMR revealed that up to 62.2% of arylglycerol-β-aryl ether structures in E. globulus are uncondensed, while in E. grandis the amount of such uncondensed structures was found to be lower than 48%. SEC analyses showed that lignins from E. grandis and softwoods associate in greater extension than lignin from E. globulus.

Elucidation of LCC bonding sites via γ-TTSA lignin degradation: crude milled wood lignin (MWL) from Eucalyptus globulus for enrichment of lignin xylan linkages and their HSQC-NMR characterization

Holzforschung ◽  
2016 ◽  
Vol 70 (6) ◽  
pp. 489-494 ◽  
Author(s):  
Daisuke Ando ◽  
Fumiaki Nakatsubo ◽  
Toshiyuki Takano ◽  
Hiroyuki Yano
Keyword(s):  
Eucalyptus Globulus ◽  
Lignin Degradation ◽  
Degradation Products ◽  
Alkali Treatment ◽  
Milled Wood Lignin ◽  
Precise Information ◽  
Lignin Removal ◽  
Nmr Characterization ◽  
Cleavage Method

Abstract The selective lignin degradation in a LCC was proceeded with the γ-TTSA method, which is a selective cleavage method for β-O-4 linkages in lignins, in order to obtain more precise information concerning LCC bonding sites. To this purpose, crude MWL from Eucalyptus globulus, containing lignin and xylan, was treated by the γ-TTSA method. This approach consists of four steps: (1) γ-tosylation, (2) thioetherification, (3) sulfonylation, and (4) mild alkali treatment. The degradation products were extracted consecutively with Et2O, EtOAc, and THF for the lignin removal, and thus the residue was enriched in LCCs. The residue was characterized by HSQC-NMR. Results indicated that the residue contained xylan and β-β substructures, although lignin was degraded. It can be concluded that the β-β substructures play an important role in the bonding sites between lignin and xylan of Eucalyptus globulus.

Effect of autohydrolysis of Eucalyptus globulus wood on lignin structure. Part 2: Influence of autohydrolysis intensity

Holzforschung ◽  
2008 ◽  
Vol 62 (6) ◽  
Author(s):  
Moritz Leschinsky ◽  
Gerhard Zuckerstätter ◽  
Hedda K. Weber ◽  
Rudolf Patt ◽  
Herbert Sixta
Keyword(s):  
Molecular Weight ◽  
Eucalyptus Globulus ◽  
Condensation Reaction ◽  
Insoluble Fraction ◽  
High Reactivity ◽  
Reactor Wall ◽  
Hydroxyl Groups ◽  
Wood Residue ◽  
Fragmentation Reactions ◽  
P Factor

Abstract Three different levels of autohydrolysis intensity, expressed as the prehydrolysis (P)-factor, were applied to Eucalyptus globulus wood at a liquor/wood ratio of 5:1. Lignin fractions were isolated from the wood residue as milled wood lignin (MWL), from the hydrolysate by centrifugation (insoluble fraction) and by ethyl acetate extraction (soluble fraction), and from the reactor wall as precipitate. With increasing autohydrolysis duration, a decrease in the content of aliphatic hydroxyl groups and of β-O-4 structures was detected in all lignin fractions, whereas the content of phenolic hydroxyl groups increased in the same order. MWL isolated from wood residue after autohydrolysis at the highest P-factor contained only half the β-O-4 structures contained in native lignin. Molecular weight distribution measurements revealed that fragmentation reactions dominated over condensation reactions in all lignin samples investigated. However, low-molecular-weight lignin dissolved in autohydrolysate exhibited extremely high reactivity towards acid-catalysed condensation reaction, which inevitably leads to the formation of sticky precipitates during storage at elevated temperature under the acid conditions prevailing.

scholarly journals Potential of Biochar Derived from Agricultural Residues for Sustainable Management

2021 ◽  
Vol 13 (15) ◽  
pp. 8147
Author(s):  
Sasiwimol Khawkomol ◽  
Rattikan Neamchan ◽  
Thunchanok Thongsamer ◽  
Soydoa Vinitnantharat ◽  
Boonma Panpradit ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Agricultural Residues ◽  
Hydroxyl Groups ◽  
Asian Countries ◽  
Heating Value ◽  
Coconut Husk ◽  
High Heating Value ◽  
Horizontal Drum ◽  
Physical And Chemical ◽  
And Chemical Properties

A horizontal drum kiln is a traditional method widely used in Southeast Asian countries for producing biochar. An understanding of temperature conditions in the kiln and its influence on biochar properties is crucial for identifying suitable biochar applications. In this study, four agricultural residues (corncob, coconut husk, coconut shell, and rice straw) were used for drum kiln biochar production. The agricultural residues were turned into biochar within 100–200 min, depending on their structures. The suitability of biochar for briquette fuels was analyzed using proximate, ultimate, and elemental analysis. The biochar’s physical and chemical properties were characterized via bulk density, iodine number, pHpzc, SEM, and FTIR measurements. All biochars had low O/C and H/C ratios and negative charge from both carbonyl and hydroxyl groups. Coconut husk and shell biochar had desirable properties such as high heating value and a high amount of surface functional groups which can interact with nutrients in soil. These biochars are thus suitable for use for a variety of purposes including as biofuels, adsorbents, and as soil amendments.

scholarly journals Fibrillar pharmacology of functionalized nanocellulose

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sam Wong ◽  
Simone Alidori ◽  
Barbara P. Mello ◽  
Bryan Aristega Almeida ◽  
David Ulmert ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Fluorescent Dyes ◽  
Pharmacokinetic Profile ◽  
Water Soluble ◽  
Size Exclusion ◽  
Hydroxyl Groups ◽  
Target Tissue ◽  
Exclusion Chromatography ◽  
Specific Accumulation

AbstractCellulose nanocrystals (CNC) are linear organic nanomaterials derived from an abundant naturally occurring biopolymer resource. Strategic modification of the primary and secondary hydroxyl groups on the CNC introduces amine and iodine group substitution, respectively. The amine groups (0.285 mmol of amine per gram of functionalized CNC (fCNC)) are further reacted with radiometal loaded-chelates or fluorescent dyes as tracers to evaluate the pharmacokinetic profile of the fCNC in vivo. In this way, these nanoscale macromolecules can be covalently functionalized and yield water-soluble and biocompatible fibrillar nanoplatforms for gene, drug and radionuclide delivery in vivo. Transmission electron microscopy of fCNC reveals a length of 162.4 ± 16.3 nm, diameter of 11.2 ± 1.52 nm and aspect ratio of 16.4 ± 1.94 per particle (mean ± SEM) and is confirmed using atomic force microscopy. Size exclusion chromatography of macromolecular fCNC describes a fibrillar molecular behavior as evidenced by retention times typical of late eluting small molecules and functionalized carbon nanotubes. In vivo, greater than 50% of intravenously injected radiolabeled fCNC is excreted in the urine within 1 h post administration and is consistent with the pharmacological profile observed for other rigid, high aspect ratio macromolecules. Tissue distribution of fCNC shows accumulation in kidneys, liver, and spleen (14.6 ± 6.0; 6.1 ± 2.6; and 7.7 ± 1.4% of the injected activity per gram of tissue, respectively) at 72 h post-administration. Confocal fluorescence microscopy reveals cell-specific accumulation in these target tissue sinks. In summary, our findings suggest that functionalized nanocellulose can be used as a potential drug delivery platform for the kidneys.

Chemical characterization and in vitro fermentation ofBrassicastraw treated with the aerobic fungus,Trametes versicolor

2011 ◽  
Vol 91 (4) ◽  
pp. 695-702 ◽  
Author(s):  
J. E. Ramirez-Bribiesca ◽  
Y. Wang ◽  
L. Jin ◽  
T. Canam ◽  
J. R. Town ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Trametes Versicolor ◽  
Lignin Degradation ◽  
Volatile Fatty Acids ◽  
Degradation Products ◽  
Chemical Characterization ◽  
Gas Production ◽  
In Vitro Fermentation ◽  
Lignin Degradation Products

Ramirez-Bribiesca, J. E., Wang, Y., Jin, L., Canam, T., Town, J. R., Tsang, A., Dumonceaux, T. J. and McAllister, T. A. 2011. Chemical characterization and in vitro fermentation of Brassica straw treated with the aerobic fungus, Trametes versicolor . Can. J. Anim. Sci. 91: 695–702. Brassica napus straw (BNS) was either not treated or was treated with two strains of Trametes versicolor; 52J (wild type) or m4D (a cellobiose dehydrogenase-deficient mutant) with four treatments: (i) untreated control (C-BNS), (ii) 52J (B-52J), (iii) m4D (B-m4D) or (iv) m4D+glucose (B-m4Dg). Glucose was provided to encourage growth of the mutant strain. All treatments with T. versicolor decreased (P<0.05) neutral-detergent fibre and increased (P<0.05) protein and the concentration of lignin degradation products in straw. Ergosterol was highest (P<0.05) in straw treated with B-52J, suggesting it generated the most fungal biomass. Insoluble lignin was reduced (P<0.05) in straw treated with B-52J and B-m4D, but not with B-m4Dg. Mannose and xylose concentration were generally higher (P<0.05) in straw treated with fungi, whereas glucose and galactose were lower as compared with C-BNS. The four treatments above were subsequently assessed in rumen in vitro fermentations, along with BNS treated with 2 mL g−1of 5 N NaOH. Concentrations of total volatile fatty acids after 24 and 48h were lower (P<0.05) in incubations that contained BNS treated with T. versicolor as compared with C-BNSor NaOH-treated BNS. Compared with C-BNS, in vitrodry matter disappearance and gas production were increased (P<0.05) by NaOH, but not by treatment with either strain of T. versicolor. Although treatment with T. versicolor did release more lignin degradation products, it did not appear to provide more degradable carbohydrate to in vitro rumen microbial populations, even when a mutant strain with compromised carbohydrate metabolism was utilized. Production of secondary compounds by the aerobic fungi may inhibit rumen microbial fermentation.

Effect of High-Temperature Defibration on the Chemical Structure of Hardwood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 51-59 ◽  
Author(s):  
P. Widsten ◽  
J.E. Laine ◽  
P. Qvintus-Leino ◽  
S. Tuominen
Keyword(s):  
High Temperature ◽  
Lignin Content ◽  
Bulk Composition ◽  
Chemical Properties ◽  
Water Extract ◽  
Fiber Surface ◽  
Phenolic Hydroxyl ◽  
Hydroxyl Groups ◽  
Surface Chemical ◽  
Alkyl Aryl

Summary The present paper aims at elucidating the effect of high-temperature defibration at different temperatures on the bulk and surface chemical properties of defibrated birch, aspen and eucalypt. The results indicate that defibration of these hardwoods results in partial depolymerization of fiber lignin via (homolytic) cleavage of interunit alkyl-aryl (β-O-4) ether bonds. This increases the phenolic hydroxyl content and produces relatively stable (phenoxy) radicals. Syringyl-type lignin is more extensively depolymerized than guaiacyl-type lignin. Defibration generates water-extractable material, which is enriched in hemicellulose-derived carbohydrates and has a substantial content of aromatic compounds rich in phenolic hydroxyl groups. The amount of water-extract and the extent of lignin interunit ether bond cleavage increase with an increase in defibration temperature. The differences between various hardwood species in this respect are small. The surface chemical composition of the fibers differs considerably from their bulk composition, but is not significantly influenced by variations in defibration temperature. Lipophilic extractives cover a large portion of the fiber surface, while the lignin content of lipophilic extractives-free fiber surfaces is 2–3 times as high as the bulk lignin content of the fibers.

scholarly journals Comparison of Three Complementary Analytical Techniques for the Evaluation of the Biosimilar Comparability of a Monoclonal Antibody and an Fc-Fusion Protein

2021 ◽  
Vol 9 ◽  
Author(s):  
Alice Demelenne ◽  
Arij Ben Yahia ◽  
Delphine Lempereur ◽  
Jacques Crommen ◽  
Anne-Catherine Servais ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Fusion Protein ◽  
Method Development ◽  
Reference Product ◽  
Degradation Products ◽  
Stress Conditions ◽  
Size Exclusion ◽  
Mild Stress ◽  
Molecular Weight Determination ◽  
Fc Fusion Protein

In this work, a monoclonal antibody, adalimumab, and an Fc-fusion protein, etanercept, were studied and compared to one of their biosimilars. Samples submitted to stress conditions (agitation and high temperature) were used for method development. The developed methods were also applied to samples reduced by beta-mercaptoethanol to evaluate their capability to distinguish the expected species. Capillary gel electrophoresis (CGE), reversed-phase liquid chromatography (RPLC), and size-exclusion chromatography (SEC) methods coupled with UV detection were used to analyze the biopharmaceuticals. Their complementarity was investigated. For further molecular weight determination, SEC-multi angle light scattering and RPLC-quadrupole time-of-flight were occasionally used. For adalimumab, a larger amount of fragments and aggregates was observed in the biosimilar compared with the reference product. For etanercept, more related species were found in the reference product. Those three separation techniques showed good complementarity. Indeed, RPLC enabled the separation of hydrophilic and hydrophobic degradation products. CGE provided good selectivity for several adalimumab fragments, and SEC was useful for the analysis of aggregates and certain fragments that cannot be separated by the other approaches. Moreover, those formulations were submitted to mild stress conditions (30°C, 300 rpm for 4 h) that mimic shipping conditions. No additional peak was found under these conditions for the two studied biopharmaceuticals.

scholarly journals Synthesis of monoketo and monohydroxy eicosanoic acids and esters with substituents at odd-numbered (3-13) carbons

2002 ◽  
Vol 67 (7) ◽  
pp. 473-480 ◽  
Author(s):  
Hulya Çelik
Keyword(s):  
Nmr Spectroscopy ◽  
High Purity ◽  
1H Nmr Spectroscopy ◽  
Methyl Esters ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Keto Acids ◽  
Physical And Chemical ◽  
Derivatives Of ◽  
And Chemical Properties

In this study, monoketo and monohydroxy eicosanoic acids and their methyl esters with the position of the substituent on odd numbered carbon atoms from 3 to 13 were synthesized with high purity. Furthermore, the semicarbazone and anilide derivatives of the obtained keto acids were prepared. They were characterized by TLC, IR and 1H-NMR spectroscopy and their physical and chemical properties were established.

scholarly journals Synthesis of L-DOPA Based Melanins with Reproducible Physic-Chemical Properties

2018 ◽  
Author(s):  
Koen Vercruysse ◽  
Jayla Moore
Keyword(s):  
Ir Spectroscopy ◽  
Enzymatic Synthesis ◽  
Chemical Properties ◽  
Size Exclusion ◽  
Synthesis Methods ◽  
Ongoing Research ◽  
Vis Spectroscopy ◽  
Exclusion Chromatography ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

This report expands our ongoing research efforts into the non-enzymatic synthesis of melanins. We have explored four different methods for the synthesis of L-DOPA based melanins and evaluated the reproducibility of some of their physic-chemical properties. The melanins were synthesized through the addition of NaOH, tyrosinate or Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>. Two different approaches for the reactions involving Fe<sup>2+</sup> and H<sub>2</sub>O<sub>2</sub> were tested: a) addition of H<sub>2</sub>O<sub>2</sub> spread out over multiple days or b) addition of H<sub>2</sub>O<sub>2</sub> in one fraction at the start of the reaction. The physic-chemical properties of the melanins explored involved: 1) retention on size exclusion chromatography column, 2) FT-IR spectroscopy, 3) UV-Vis spectroscopy and 4) the capacity to reduce a redox dye, dichlorophenolindophenol. Overall the results obtained indicated that 1) the various synthesis methods lead to melanins with reproducible physic-chemical properties, 2) that the melanins synthesized in the presence of Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub> are distinctly different from the melanins synthesized in the presence of NaOH or tyrosinate and 3) that no distinctly different melanins were generated when comparing the two different synthesis approaches involving Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>. Only the melanins synthesized in the presence of Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub> appeared to possess the capacity to reduce dichlorophenolindophenol.

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