A critical review on the analysis of lignin carbohydrate bonds

Giummarella, Nicola; Pu, Yunqiao; Ragauskas, Arthur J.; Lawoko, Martin

doi:10.1039/c8gc03606c

Cited by 236 publications

(158 citation statements)

References 134 publications

Supporting

Mentioning

147

Contrasting

Order By: Relevance

“…61 Covalent bonding may occur between the polysaccharide chains and lignin residues, creating lignincarbohydrate complexes (LCC). [61][62][63] These may either originate from native structures in wood or form through reactions that occur during the extraction process.…”

Section: Hemicellulosesmentioning

confidence: 99%

Strategies for structuring diverse emulsion systems by using wood lignocellulose-derived stabilizers

Mikkonen

2020

Green Chem.

View full text Add to dashboard Cite

Wood biomass is an abundant renewable source of materials, but due to the accelerating depletion of natural resources, it is important to explore new ways to use it in a more sustainable manner. Modern technologies enable the recovery and valorization of the main components of wood-namely, cellulose, lignin, and hemicelluloses-contributing to sustainability. However, the method of isolation and resulting structure and purity of lignocellulosic materials determine their functionality and applicability. This review discusses the properties of all three main wood-based compounds that can stabilize emulsions, a class of industrial dispersions that are widely used in life science applications and chemicals. Due to the multibillion-dollar annual market for hydrocolloids, the food, pharmaceutical, cosmetic, coating, and paint industries are actively seeking new sustainable emulsion stabilizers that fulfill the demanding requirements regarding safety and functionality. Wood-derived stabilizers facilitate various mechanisms involved in emulsion stabilization: (1) development of amphiphilic structures that decrease interfacial tension, (2) stabilization of interfaces by particles according to the Pickering theory, and (3) increase in the viscosity of emulsions' continuous phase. This review presents pathways for treating cellulose, lignin, and hemicelluloses to achieve efficient stabilization and provides suggestions for their broad use in emulsions.

show abstract

Section: Hemicellulosesmentioning

confidence: 99%

Strategies for structuring diverse emulsion systems by using wood lignocellulose-derived stabilizers

Mikkonen

2020

Green Chem.

View full text Add to dashboard Cite

show abstract

“…The HSQC spectra for GGM and GX are presented in Figures 4, 5, respectively. The spectra of samples dissolved in d 6 -DMSO were tentatively identified based on existing data for GGM (Hannuksela and Hervé du Penhoat, 2004;Kim and Ralph, 2014;Berglund et al, 2019), for GX (Teleman et al, 2000(Teleman et al, , 2002Rencoret et al, 2012;Kim and Ralph, 2014), for lignin (Liitiä et al, 2003), and for LCC γ-ester (Giummarella et al, 2019), combined with the HSQC-TOCSY NMR spectra (presented in Figures S1A,B). Furthermore, the centrifuged fractions GGMphe and GX-phe were acetylated prior to analysis to improve solubility in d 6 -DMSO.…”

Section: Structural Characterization Of Starting Hemicelluloses Ggm Amentioning

confidence: 99%

“…The starting hemicelluloses also contained -CH 2 -protons connected to ester functionality. For GX (Figure 5), the signal at 4.30/62.92 ppm was assigned to the γ-proton of the β-O-4-structure linked to MeGlcA through an ester bond, which is also known as the γ-ester type LCC bond (Li and Helm, 1995; Giummarella et al, 2019). In addition, the signal at 4.30/83.46 ppm was assigned to the β-proton belonging to the same LCC-bonding pattern type, confirming that γ-ester LCC bonds must be rather frequent in GX hemicelluloses produced by the PHWE process.…”

Section: Structural Characterization Of Starting Hemicelluloses Ggm Amentioning

confidence: 99%

“…In addition, the signal at 4.30/83.46 ppm was assigned to the β-proton belonging to the same LCC-bonding pattern type, confirming that γ-ester LCC bonds must be rather frequent in GX hemicelluloses produced by the PHWE process. According to model compound studies using smaller synthesized molecules, as well as to those using lignin dehydropolymer (DHP), urunosyl units can migrate to the γ-position (Li and Helm, 1995;Giummarella et al, 2019), FIGURE 7 | Chemical structures identified by NMR. The symbols and abbreviations used in NMR spectra are G (Glc), M (Man), MGA (MeGlcA), X (Xyl), A (β-O-4/β-aryl ether), B (β-β/resinol), C (β-5/phenyl coumaran), A Est (β-O-4 connected with MeGlcA by γ-ester bond), Est (acyl ester), G Ar (guaiacyl), and S Ar (syringyl).…”

Section: Structural Characterization Of Starting Hemicelluloses Ggm Amentioning

confidence: 99%

“…In addition to non-covalent interactions, the presence of covalently bound lignin-carbohydrate complexes (LCCs) was suggested decades ago (Fengel and Wegener, 1983). However, even today, unequivocal proof of different types of LCCs is lacking, because these structures have low frequencies and because structural modifications may occur during their isolation for characterization (Giummarella et al, 2019). Recently, isolation and characterization of the α-ether type LCC was successfully performed (Nishimura et al, 2018) and was made possible by the development of a methodology for enriching LCCs and characterizing by nuclear magnetic resonance (NMR) spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Lignin-Rich PHWE Hemicellulose Extracts Responsible for Extended Emulsion Stabilization

et al. 2019

View full text Add to dashboard Cite

Wood hemicelluloses have an excellent capacity to form and stabilize oil-in-water emulsions. Galactoglucomannans (GGM) from spruce and glucuronoxylans (GX) from birch provide multifunctional protection against physical breakdown and lipid oxidation in emulsions. Phenolic residues, coextracted with hemicelluloses using the pressurized hot water (PHWE) process, seem to further enhance emulsion stability. According to hypothesis, phenolic residues associated with hemicelluloses deliver and anchor hemicelluloses at the emulsion interface. This study is the first to characterize the structure of the phenolic residues in both GGM-and GX-rich wood extracts and their role in the stabilization of emulsions. PHWE GGM and GX were fractionated by centrifugation to obtain concentrated phenolic residues as one fraction (GGM-phe and GX-phe) and partially purified hemicelluloses as the other fraction (GGM-pur and GX-pur). To evaluate the role of each fraction in terms of physical and oxidative stabilization, rapeseed oil-in-water emulsions were prepared using GGM, GX, GGM-pur, and GX-pur as stabilizers. Changes in droplet-size distribution and peroxide values were measured during a 3-month accelerated storage test. The results for fresh emulsions indicated that the phenolic-rich fractions in hemicelluloses take part in the formation of emulsions. Furthermore, results from the accelerated storage test indicated that phenolic structures improve the long-term physical stability of emulsions. According to measured peroxide values, all hemicelluloses examined inhibited lipid oxidation in emulsions, GX being the most effective. This indicates that phenolic residues associated with hemicelluloses act as antioxidants in emulsions. According to chemical characterization using complementary methods, the phenolic fractions, GGM-phe and GX-phe, were composed mainly of lignin. Furthermore, the total carbohydrate content of the phenolic fractions was clearly lower compared to the starting hemicelluloses GGM and GX, and the purified fractions GGM-pur and GX-pur. Apparently, the phenolic structures were enriched in the GGM-phe and GX-phe fractions, which was confirmed by NMR spectroscopy as well as by other characterization methods. The frequency of the main bonding pattern in lignins, the β-O-4 structure, was clearly very high, suggesting that extracted lignin remains in native form. Furthermore, the lignin carbohydrate complex of γ-ester type was found, which could explain the excellent stabilizing properties of PHWE hemicelluloses in emulsions.

show abstract

Pulp

Brännvall¹

2020

Kirk-Othmer Encyclopedia of Chemical Technology

View full text Add to dashboard Cite

Global virgin pulp production in 2017 was 196 million tonnes. Combined with recycled fibers, the global paper and paperboard production was 413 million tonnes with packaging paper being dominant. The two major chemical processes, kraft and sulfite, cook wood chips at high temperature and pressure to liberate fibers after about 90% of the lignin is dissolved to allow the release of pulp fibers without mechanical force. The mass yield of chemical pulp is 45–55% because most hemicelluloses and some cellulose are also dissolved. Kraft pulp represented 83% of a total chemical pulp production of 123 million tonnes in 2018. Mechanical pulp fibers are obtained by pure mechanical action such as grinding and refining and are called groundwood pulp (GWP) and thermomechanical pulp (TMP), respectively. However, because of its global dominance, this article focuses on kraft chemical pulp. The wood anatomy and chemical composition and fiber dimensions and properties of different species are described. The ultrastructure of pulp fibers and cell walls is interpreted in terms of their relevance for lignin removal during pulping and the structural properties of the final chemical pulp, respectively. Flow sheets for the production of softwood and hardwood bleached kraft and sulfite pulps are presented. Different unit operations of chemical pulping and the governing physical and chemical phenomena are described. The article reviews the mechanisms and kinetics of delignification and carbohydrate degradation and retention that occur inside the wood chips during impregnation with and subsequent pulping in cooking liquor. Oxygen delignification and pulp bleaching conclude this article.

show abstract

A critical review on the analysis of lignin carbohydrate bonds

Abstract: This review highlights the challenges of analyzing lignin–carbohydrate bonds, which are hypothesized to contribute to the recalcitrance in biomass fractionation.

Cited by 236 publications

References 134 publications

Strategies for structuring diverse emulsion systems by using wood lignocellulose-derived stabilizers

Strategies for structuring diverse emulsion systems by using wood lignocellulose-derived stabilizers

Lignin-Rich PHWE Hemicellulose Extracts Responsible for Extended Emulsion Stabilization

Pulp

Contact Info

Product

Resources

About