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In this work, sodium lignosulfonate (SL) was introduced in the hydrothermal preparation of phenol-formaldehyde (PF) resin sphere that was subsequently used as a green reducer and support for synthesis of Ag nanoparticles (Ag NPs). The results showed that the addition amount of SL had a remarkable effect on the size of the SL incorporated PF (SLPF) spheres and the smallest particle size was obtained when 20% of SL (based on phenol mass) was added. The addition of SL increased the surface area and negative charge of SLPF spheres, which enhanced the Ag NPs loading amount accordingly. Moreover, SL also prevented Ag NPs from aggregating effectively, resulting in the high-density loading of small size Ag NPs on the SLPF spheres. Therefore, the as-prepared Ag@SLPF composites exhibited significantly enhanced catalytic activities in the 4-nitrophenol reduction than that of SL-free Ag@PF. Besides, the Ag@SLPF catalyst demonstrated superior recyclability owing to strong anchoring between the Ag NPs and the support. Consequently, the work demonstrates the incorporation of SL enables the green formation of high-density and tunable Ag NPs on the SLPF support and then endows the composite catalyst with enhanced catalytic performance, which presents a promising value-added application of lignosulfonate for functional catalyst preparation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Hypothesis: Amphiphilic character of surfactants drives them at the interface of dispersed systems, such as emulsions. Hemicellulose-rich wood extracts contain assemblies (lignin-carbohydrate complexes, LCC) with natural amphiphilicity, which is expected to depend on their chemical composition resulting from the isolation method. Lignin-derived phenolic residues associated with hemicelluloses are hypothesized to contribute to emulsions' interfacial properties and stability., Experiments: We investigated the role of phenolic residues in spruce hemicellulose extracts in the stabilization of oil-in-water emulsions by physical and chemical approach. Distribution and changes occurring in the phenolic residues at the droplet interface and in the continuous phase were studied during an accelerated storage test. Meanwhile, the physical stability and lipid oxidation in emulsions were monitored., Findings: Naturally associated lignin residues in GGM act as vehicles for anchoring these hemicelluloses into the oil droplet interface and further enable superior stabilization of emulsions. By adjusting the isolation method of GGM regarding their phenolic profile, their functionalities, especially interfacial behavior, can be altered. Retaining the native interactions of GGM and phenolic residues is suggested for efficient physical stabilization and extended protection against lipid oxidation. The results can be widely applied as guidelines in tailoring natural or synthetic amphiphilic compounds for interfacial stabilization., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Pyrolysis was demonstrated to investigate the thermal decomposition characteristics and potential of lignin-rich cotton by-products cotton exocarp (CE) and spent mushroom substrate consisted of cotton by-products (MSC) for biorefineries. The chemical component and structure alteration of CE and MSC was found to affect their thermochemical behaviors. The bio-oil yield from CE was 58.13wt% while the maximum yield from MSC was 45.01% at 600°C. The phenolic compounds obtained from CE and MSC were 33.9% and 39.2%, respectively. The yield of acetic acid from MSC between 400 and 600°C was about 30-38% lower than that from CE, which suggests the high quality of bio-oil was obtained. Biochar from MSC via slow pyrolysis had a high mass yield (44.38wt%) with well-developed pore structure., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this study, the adsorption and desorption characteristics of six macroporous resins including XAD-7HP, XAD-16, HP-20, HP-2MGL, SP-207 and SP-825 for enrichment of adlay bran free phenolics were studied. XAD-16, SP-207 and SP-825 were chosen for further study due to their strong adsorption and desorption capacities. XAD-16, SP-207 and SP-825 had similar phenolics adsorption/desorption behaviors. Pseudo-second-order kinetics model and Freundlich isotherm model were suitable for describing the whole exothermic and physical adsorption processes of adlay bran free phenolics on XAD-16, SP-207 and SP-825. After treatment with gradient elution on XAD-16 resin column, the free phenolics were mostly enriched (from 89.61 to 1015.26mg/100g) in 50% ethanol fraction. The oxygen radical absorbance capacity of 50% ethanol fraction was eight times higher than that of the crude extract. Therefore, the production of highly concentrated phenolics might expand the application of adlay bran used as a bioactive ingredient in functional food., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

This study investigated the thermal decomposition characteristics and pyrolytic products of anaerobic digested rice straw (ADRS) by thermogravimetric (TG) and pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS) analysis. Compared with the raw rice straw (RS), the thermal decomposition temperature of ADRS was shifted to higher temperature zone and the second decomposition zone of cellulose (Toffset(c)-Tpeak) became narrower (14 °C less), which indicated that the composition of rice straw were changed significantly by the anaerobic digestion pretreatment. Py-GC/MS analysis showed that the quality of the bio-oil and the selectivity of pyrolytic products could be obviously improved by anaerobic digestion. The total yields of alcohols, acids, aldehydes, furans, anhydrosugars, and ketones pyrolysis substances decreased, while the yield of phenols increased. The yield of 4-Vinylphenol (4-VP) increased from 29.33%, 8.21% and 5.76% to 34.93%, 12.46% and 7.68% at 330, 450 and 650 °C, respectively, after anaerobic digestion., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The specific elimination of lignin derivatives from wood hydrolysate without sugar loss has great practical significance to biorefinery and bioenergy. In the present study, a process consisting of calcium hydroxide and anion exchange resin treatments was developed for the purpose of selective removal of lignin from wood prehydrolysis liquor (PHL). Particular emphasis was made on the ionization of phenolic lignin, and the subsequent binding to metallic salts. It was observed that phenolic hydroxyl groups (PhOH) in lignin played an important role in lignin removal. The results showed that up to 95.2% lignin was removed from PHL with 78.8% sugar recovery. This suggested that the proposed process is highly specific to lignin, and therefore can be envisaged as a great contribution to wood-sugar production or bioenergy conversion., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

With the growing attention on estrogenic effect of Bisphenol A (BPA), the application of BPA derivatives like Bis-GMA in dental materials has also been doubted. In this research, new BPA free dental resin systems were prepared with synthesized dendritic macromer G-IEMA, UDMA, and TEGDMA. Physicochemical properties, such as double bond conversion, polymerization shrinkage, flexural strength and modulus, fracture energy, water sorption and solubility of BPA free resin formulations were investigated. Bis-GMA/TEGDMA resin system was used as a control. Results showed that the prepared BPA free resins could have higher double bond conversion, comparable or lower polymerization shrinkage and water sorption, and lower water solubility, when compared with Bis-GMA/TEGDMA resin. Though flexural strength and modulus of prepared BPA free polymers were lower than those of Bis-GMA/TEGDMA polymer, BPA free polymers had higher fracture energies and showed plastic deformation prior to fracture, all of these two phenomena showed that BPA free polymers in this research might have higher fracture toughness which would be good for the service life of dental materials., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Pinoresinol structures, featuring a β-β'-linkage between lignin monomer units, are important in softwood lignins and in dicots and monocots, particularly those that are downregulated in syringyl-specific genes. Although readily detected by NMR spectroscopy, pinoresinol structures largely escaped detection by β-ether-cleaving degradation analyses presumably due to the presence of the linkages at the 5 positions, in 5-5'- or 5-O-4'-structures. In this study, which is aimed at helping better understand 5-linked pinoresinol structures by providing the required data for NMR characterization, new lignin model compounds were synthesized through biomimetic peroxidase-mediated oxidative coupling reactions between pre-formed (free-phenolic) coniferyl alcohol 5-5'- or 5-O-4'-linked dimers and a coniferyl alcohol monomer. It was found that such dimers containing free-phenolic coniferyl alcohol moieties can cross-couple with the coniferyl alcohol producing pinoresinol-containing trimers (and higher oligomers) in addition to other homo- and cross-coupled products. Eight new lignin model compounds were obtained and characterized by NMR spectroscopy, and one tentatively identified cross-coupled β-O-4'-product was formed from a coniferyl alcohol 5-O-4'-linked dimer. It was demonstrated that the 5-5'- and 5-O-4'-linked pinoresinol structures could be readily differentiated by using heteronuclear multiple-bond correlation (HMBC) NMR spectroscopy. With appropriate modification (etherification or acetylation) to the newly obtained model compounds, it would be possible to identify the 5-5'- or 5-O-4'-linked pinoresinol structures in softwood lignins by 2D HMBC NMR spectroscopic methods. Identification of the cross-coupled dibenzodioxocin from a coniferyl alcohol 5-5'-linked moiety suggested that thioacidolysis or derivatization followed by reductive cleavage (DFRC) could be used to detect and identify whether the coniferyl alcohol itself undergoes 5-5'-cross-linking during lignification., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Selective production of 4-ethylphenolics from lignin via mild hydrogenolysis was reported in this short communication. The hydrogenolysis of lignin was carried out in an autoclave with 65 vol.% ethanol/water as solvent, with 5% Ru/C, Pd/C and Pt/C as catalysts. The influences of catalysts, lignin species, and reaction conditions including reaction temperature, reaction time, and initial H(2) pressure on yield of target compounds were investigated. 3.1% 4-Ethylphenol and 1.3% 4-ethylguaiacol based on lignin could be obtained simultaneously from hydrogenolysis of corn stalk lignin, which is approximate to the yield obtained from petrochemical route. The results of this work showed that this novel method is a quite promising technique for the substitution of petrochemical route., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A new biotechnological procedure using laccase in combination with a hydrophobic phenolic compound (lauryl gallate) for the hydrophobization of cellulose fibres and internal sizing of paper was developed. Cellulose fibres from hardwood kraft pulp were incubated with laccase (Lac), in combination with lauryl gallate (LG). The Lac-LG treatment resulted in the internal sizing of paper, and also in significantly reduced water penetration in the handsheets and wettability of the paper surface. Paper was found not to be effectively rendered hydrophobic by LG alone. SEM images of the fibre network revealed the presence of the sizing agent: a product of the reaction between laccase and lauryl gallate. Binding of lauryl gallate to cellulose fibres was suggested by the increase in kappa number of the pulp and further confirmed by IR spectroscopy., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Study on the EtOAc soluble fraction from the bark of Populus ussuriensis Kom. resulted in the isolation of three phenolic glycosides, including populoside (1), 7-O-ρ-coumaroylsalirepin (2) and 7-O-caffeoylsalirepin (3), among which 3 is a new compound. The structures of these compounds were elucidated on the basis of spectroscopic evidence. Phenolic glycosides 1-3 exhibited excellent antioxidant activity, evaluated in the ABTS⁺ radical scavenging assay.

The antioxidant activity of the phenolic compounds present in industrial black liquors obtained from the two cooking processes (kraft and sulphite) used in Portugal to produce Eucalyptus globulus pulp was evaluated. The black liquors treated at several pH values were extracted with ethyl acetate. Phenolic fractions were further separated by liquid chromatography of the crude extracts of kraft liquor at pH = 6 and sulphite liquor at the original pH. Total phenolic content was determined in terms of gallic acid equivalents (Folin-Ciocalteu colorimetric method), and the antioxidant activity in the crude extracts at several pH values and in the separated fractions was measured using the DPPH test for radical scavenging capacity. The total phenolic content of crude extracts and separated fractions ranged from 92.7 to 181.6 and from 91.6 to 1,099.6 mg GAE/g, respectively, while the antioxidant activity index (AAI) ranged from 2.20 to 3.41 and from 2.21 to 11.47 respectively, showing very strong antioxidant activity in all studied cases. The fractions separated by column chromatography were submitted to mass spectrometry analysis and the results were compared to others in the literature of natural products, mainly from Eucalyptus, and the characteristic bands of functional groups were identified by ¹H-NMR and FTIR. These methods allowed the identification of 17 phenolic compounds.

Flax and sisal pulps were treated with two laccases (from Pycnoporus cinnabarinus, PcL and Trametes villosa, TvL, respectively), in the presence of different phenolic compounds (syringaldehyde, acetosyringone and p-coumaric acid in the case of flax pulp, and coniferaldehyde, sinapaldehyde, ferulic acid and sinapic acid in the case of sisal pulp). In most cases the enzymatic treatments resulted in increased kappa number of pulps suggesting the incorporation of the phenols into fibres. The covalent binding of these compounds to fibres was evidenced by the analysis of the treated pulps, after acetone extraction, by pyrolysis coupled with gas chromatography/mass spectrometry in the absence and/or in the presence of tetramethylammonium hydroxide (TMAH) as methylating agent. The highest extents of phenol incorporation were observed with the p-hydroxycinnamic acids, p-coumaric and ferulic acids. The present work shows for the first time the use of analytical pyrolysis as an effective approach to study fibre functionalization by laccase-induced grafting of phenols., (Copyright 2010 Elsevier Ltd. All rights reserved.)

The natural phenolic compounds syringaldehyde and vanillin were compared to the synthetic mediators 1-hydroxybenzotriazole, violuric acid and promazine in terms of boosting efficiency in a laccase-assisted biobleaching of eucalyptus kraft pulp. Violuric acid and 1-hydroxybenzotriazole revealed to be the most effective mediators of the bioprocess. Nevertheless, laccase-syringaldehyde system also improved the final pulp properties (28% delignification and 63.5% ISO brightness) compared to the process without mediator (23% and 61.5% respectively), in addition to insignificant denaturation effect over laccase. The efficiency of the biobleaching process was further related to changes in non-conventionally used optical and chromatic parameters of pulp, such as (L*), chroma (C*) and dye removal index (DRI) showing good correlation. Adverse coupling reactions of the natural phenolic mediators on pulp lignin were predicted by electrochemical studies, demonstrating the complexity of the laccase-mediator reaction on pulp.

Recently we demonstrated that in inflammatory bowel disease (IBD) macrophage-oxidative burst activity is increased and NADPH oxidase mRNA is induced. The herbal phenylethanoid acteoside isolated from Plantago lanceolata L. was shown to exhibit anti-oxidative potential. Using the dextran sulphate sodium (DSS)-induced colitis model, in this study we have assessed whether systemic application of acteoside affects colitis. Colitis was induced by DSS in Balb/c mice. Treatment with acteoside (120, 600 microg/mouse/day) was performed intraperitoneally. The colon lengths were determined. Colonic tissue was scored histologically (max. score 8) by a blinded investigator. T cells isolated from mesenteric lymph nodes (MLN) were stimulated with anti-CD3 antibody in the presence of interleukin (IL)-2 (final concentration 10 U/ml). After incubation for 24 h, IL-1beta, IL-6, IL-12 tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma levels in supernatants were analysed by the beadlyte cytokine detection system. Histological scoring of colonic tissue revealed that application of acteoside was followed by a significantly improved histological score. In acute colitis the histological score was 3.2 with acteoside versus 5.2 with phosphate-buffered saline (PBS) (P < 0.02). In chronic colitis both 120 microg (3.3 versus 5.2) or 600 microg acteoside (3.0 versus 5.2) significantly ameliorated colitis (both P < 0.02). Stimulated MLN from mice with chronic DSS-induced colitis treated with acteoside showed a significant down-regulation of IFN-gamma secretion (195 pg/ml with 600 microg acteoside versus 612 pg/ml with PBS, P < 0.02). Inhibition of oxidative burst activity with acteoside reduced mucosal tissue damage in DSS colitis and could be a therapeutic alternative for IBD treatment. Further studies of this agent are warranted.

Treatment of wheat straw with hot water at 80-95 degrees C for 0.5 h at pH 6.0-8.0 released 41.0-53.0% of the original lipophilic extractives. The chemical compositions of six lipophilic extractives were determined by GC on a medium-length high-temperature capillary column without derivatization, thus giving a method for direct determination of individual components of free fatty and resin acids, sterols, waxes, sterol esters, and triglycerides. The extracts contained 68.7-75.8% lipophilic substances, comprising mainly free fatty acids (25.8-48.4%), waxes (9.4-27.0%), sterols (4.1-8.0%), triglycerides (3.3-11.0%), and sterol esters (2.6-5.1%). Minor amounts of diglycerides (0.3-0.5%), resin acid (0.5-3.1%), and phenolic compounds (0.9-3.6%) were also quantitatively determined in the extractives.

In the presence of substrates such as Remazol Blue and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate) (ABTS), laccases Coriolus (Trametes) versicolor can also oxidize non-phenolic lignin model compounds. Veratryl alcohol (I) and 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-propane-1,3-diol (III) were oxidized by laccase and mediator to give the alpha-carbonyl derivatives. The beta-1 lignin model dimer, 1-(3,4-dimethoxyphenyl)-2-phenoxy-ethane-1,2-diol (II) was cleaved by laccase in the presence of ABTS to give veratraldehyde and benzaldehyde. On the basis of these observations, we propose that laccase is capable of oxidizing both phenolic and non-phenolic moieties of lignin but that the latter is dependent on the co-presence of primary laccase substrates.