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Hemicellulose extracted from ecalyptus APMP pulping waste liquor and undergoes etherification modification to produce carboxymethyl hemicellulose (CMHC). Subsequently, CMHC undergoes esterification reaction with p-hydroxybenzoic acid to synthesize a novel polysaccharide-based preservative known as carboxymethyl hemicellulose p-hydroxybenzoate (P-CMHC). The synthesis conditions of P-CMHC were optimized using the response surface methodology, resulting in an optimal esterification condition that achieved a degree of substitution of 0.232. P-CMHC exhibits excellent antioxidant activity, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activities. Additionally, it demonstrates favorable hygroscopic and moisturizing properties. Thiazole blue (MTT) experiments evaluating cell proliferation rate indicate that P-CMHC possesses negligible cytotoxicity, making it a promising, safe, and healthy preservative. Consequently, it can be considered as a new material for applications in the fields of biomedicine, food, and cosmetics., Competing Interests: Declaration of competing interest We wish to draw the attention of the Editor to the following facts which may be considered as potential conflicts of interest and to significant financial contributions to this work. We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us. We confirm that we have given due consideration to the protection of intellectual property associated with this work and that there are no impediments to publication, including the timing of publication, with respect to intellectual property. In so doing we confirm that we have followed the regulations of our institutions concerning intellectual property., (Copyright © 2023. Published by Elsevier Ltd.)

In this study, novel redox-sensitive nanoparticles based on xylan-lipoic acid (Xyl-LA) conjugate were developed for tumor targeted delivery of niclosamide (Nic) in cancer therapy. The niclosamide loaded xylan-lipoic acid conjugate nanoparticles (Xyl-LA/Nic NPs) showed redox responsive behaviour in presence of reductive glutathione (GSH), which indicate their suitability for intracellular drug release. The obtained Xyl-LA/Nic NPs exhibited uniform particle size (196 ± 1.64 nm), high loading capacity (~28.6 wt %) and excellent blood compatibility. The anticancer activity of the Niclosamide and the Xyl-LA/Nic NPs against the colon carcinoma cell lines (HCT-15, Colo-320) were evaluated by MTT assay and the overall results indicate that the Xyl-LA/Nic NPs significantly enhanced the therapeutic efficiency of niclosamide in cancer therapy., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This work presents a kinetic investigation of dilute sulfuric acid hydrolysis of bleached hardwood kraft pulp. The temperature-time dependence shows fast xylose extraction during the initial period of the process, while the glucose content increases slowly and permanently over the period. A conversion of xylose into furfural and furfural-derived chromophores is observed. It is established that only a low-brightness microcrystalline cellulose when a degree of polymerization below 300 can be obtained from hardwood pulp. The study of the acid hydrolysis kinetics, with respect to the degree of polymerization of microcrystalline cellulose, shows that the modified Prout-Tompkins equation describes most adequately the process. According to that kinetic model, the hydrolysis rate depends on a combination of chemical interaction and diffusion processes. It is evident that the activation energy does not change in the course of the process, i.e. the cellulose active centers do not change their activity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Diatoms secrete extracellular polymeric substances (EPS), or mucilage, around the cell wall that may serve to aid in motility and form a discrete layer that may help maintain thicker layers of EPS that have a greater role in adhesion. Mucilage molecules adhere to the diatom frustules, which are biosilica skeletons that develop from the diatom cell walls. Here, molecular dynamics methods were used to determine the characteristics of mucilage molecules as a function of pore size; notably 1,4-α-D-galacturonic acid, 1,4-β-glucuronic acid and 1,4-β-D-mannuronic acid. These uronic acids differ from each other in structure and extensibility as a function of their folding characteristics. Here, we find that when overlain upon a pore, mucilage molecules try to return to their native folded states but are restrained by their interactions with the silica surfaces. Furthermore, the extensibility of mucilage molecules over pore spaces affects the extent of mechanical energy required to straighten them. As such, different EPS molecules will affect sliding, friction and adhesion to subsequent layers of EPS in different ways. We conclude that higher EPS extensibility is homonymous with higher adhesive or frictive resistance since the molecules will be able to strain more before they reach the most extended (and thus rigid) conformation. The research herein is applicable to modern engineering as it yields insight into the biomimetic design of molecules and surfaces for improved adhesion or motility., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

N,N,N-trimethyl chitosan (TMC) is a quaternized chitosan derivative with excellent solubility in aqueous solutions. It has been extensively studied as an absorption enhancer, antibacterial agent and gene vector due to its ability to form complexes with anionic gels or macromoleculars. However, the research which describes the process of TMC preparation and its new applications has not been fully reviewed. In this paper, recent progress regarding different TMC preparation methods and its characterization and application in different fields is presented. Key findings are compared and summarized and some topics for further study are suggested., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In vivo generated deuterated bacterial cellulose, cultivated from 100% deuterated glycerol in D2O medium, was analyzed for deuterium incorporation by ionic liquid dissolution and (2)H and (1)H nuclear magnetic resonance (NMR). A solution NMR method of the dissolved cellulose was used to determine that this bacterial cellulose had 85% deuterium incorporation. Acetylation and (1)H and (2)H NMR of deuterated bacterial cellulose indicated near equal deuteration at all sites of the glucopyranosyl ring except C-6 which was partly deuterated. Despite the high level of deuterium incorporation no significant differences in the molecular and morphological properties were observed for the deuterated and protio bacterial cellulose samples. The highly deuterated bacterial cellulose presented here can be used as a model substrate for studying cellulose biopolymer properties via future small angle neutron scattering (SANS) studies., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

This work describes the structural changes of bagasse hemicelluloses during the cooking process involving active oxygen (O(2) and H(2)O(2)) and solid alkali (MgO). The hemicelluloses obtained from the bagasse raw material, pulp, and yellow liquor were analyzed by high-performance anion-exchange chromatography (HPAEC), gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), and (1)H-(13)C 2D hetero-nuclear single quantum coherence spectroscopy (HSQC). The results revealed that the structure of the bagasse hemicelluloses was L-arabino-(4-O-methylglucurono)-D-xylan. Some sugar units in hemicelluloses were oxidized under the cooking conditions. Additionally, the backbones and the ester linkages of hemicelluloses were heavily cleaved during the cooking process., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Norway spruce O-acetyl-galactoglucomannans (GGM) are water-soluble hemicelluloses that have potential to be produced in large scale as a side product of the mechanical pulping industry or by hot-water extraction of wood. Chemical modification is often needed to tailor such water-soluble polysaccharides into industrially valuable compounds. In this work, treatment of GGM with butyric and benzoic anhydride in pyridine/dimethylformamide rendered GGM derivatives, which were hydrophobic and partially soluble in organic solvents. The degree of substitution can be adjusted by varying the quantity of the reagent and reaction temperature. The dn/dc value for the benzoyl ester of GGM was determined in 0.05 M LiBr DMSO in order to obtain accurate molar mass analysis with SEC-MALLS-RI. Novel substances with adjusted hydrophobicity can thus be prepared on one step synthesis from natural hemicelluloses, which then showed a slight increase in the molar mass upon esterification., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Ru/MCM-41 catalyst prepared by an impregnation-formaldehyde reduction method showed higher catalytic activity and sorbitol selectivity than other catalysts in the hydrogenation of glucose. SEM and XRD indicated the partial surface properties of Ru/MCM-41. Moreover, Ru dispersion and Ru surface area of Ru/MCM-41 were determined by pulse chemisorption, and the result further proved that Ru/MCM-41 had higher catalytic activity. A catalyst recycling experiment demonstrated that Ru/MCM-41 was a better catalyst and it could be reused three or four times. A speculated mechanism was proposed to illustrate the detailed process of d-glucose hydrogenation to produce sorbitol., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The C-6 unit of methyl α-D-galactopyranoside was selectively modified by combining enzymatic oxidation with an indium-mediated allylation reaction. The Barbier-Grignard type reaction, where a carbonyl group reacts with an allyl halide, proceeds in aqueous solution, even with water as the only solvent; thus carbohydrates can be modified without the need for drying or protection-deprotection steps. The corresponding homoallyl alcohols are produced in high yields of >90% in the reactions with allyl bromide and cinnamyl chloride. The main products were isolated and characterized by GC-MS and NMR spectroscopy., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Acetylated galactoglucomannans (GGMs) are the main hemicellulose type in most softwood species and can be utilized as, for example, bioactive polymers, hydrocolloids, papermaking chemicals, or coating polymers. Acetylation of spruce GGM using acetic anhydride with pyridine as catalyst under different conditions was conducted to obtain different degrees of acetylation on a laboratory scale, whereas, as a classic method, it can be potentially transferred to the industrial scale. The effects of the amount of catalyst and acetic anhydride, reaction time, temperature and pretreatment by acetic acid were investigated. A fully acetylated product was obtained by refluxing GGM for two hours. The structures of the acetylated GGMs were determined by SEC-MALLS/RI, (1)H and (13)C NMR and FTIR spectroscopy. NMR studies also indicated migration of acetyl groups from O-2 or O-3 to O-6 after a heating treatment in a water bath. The thermal stability of the products was investigated by DSC-TGA., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

Hemicellulose-based hydrophobic biomaterials with degrees of substitution ranging from 0.46 to 1.54 were synthesized under mild conditions in homogeneous media (N,N-dimethylformamide-lithium chloride) by reacting the native wheat straw hemicellulosic polymers with lauroyl chloride using 4-dimethylaminopyridine as a catalyst. Other catalysts such as N-bromosuccinimide, N-methyl pyrrolidine, N-methyl pyrrolidinone, and pyridine were also investigated. Under optimum reaction conditions (2 equiv of lauroyl chloride and triethylamine per hydroxyl group, 5% 4-dimethylaminopyridine, 40 degrees C, 35 min), a high DS value of 1.54 was obtained. The biomaterials were characterized by FT-IR spectroscopy and (13)C NMR spectroscopy as well as by thermal analysis. The results showed that the lauroylation occurred preferably at the C-3 hydroxyl group of beta-D-Xylp units in the hemicelluloses, and the thermal stability of the hydrophobic polymers increased by esterification.

A series of novel water-soluble hemicellulosic derivatives, containing carbamoylethyl and carboxyethyl groups, were heterogeneously synthesized from wheat-straw hemicelluloses with acrylamide (AA) under alkaline conditions. The factors such as reaction temperature, reaction time, molar ratio of catalysis to xylose unit in hemicelluloses and molar ratio of acrylamide to xylose unit in hemicelluloses, were investigated. The average degree of substitution (DS) was calculated by (1)H NMR spectroscopy. DS values up to 0.23 in a one-step synthesis of hemicelluloses derivatives were obtained. Under optimum conditions (60°C, NaOH to xylose unit in hemicelluloses molar ratio of 0.8, AA to xylose unit in hemicelluloses molar ratio of 8.0, reaction time of 1h) an expected ratio of carbamoylethyl group to carboxyethyl group of 4.8 in the hemicellulosic derivatives was obtained. The structural features of the hemicellulosic derivatives were characterized by FTIR, NMR spectroscopy, and by elemental analysis. The current work provides a facile method for the synthesis of hemicellulose derivatives with bifunctional groups, which could be used as wet-end additives in the papermaking industry.

The homogeneous chemical modification of sugarcane bagasse cellulose with succinic anhydride using 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid as a reaction medium was studied. Parameters investigated included the molar ratio of succinic anhydride/anhydroglucose units in cellulose in a range from 2:1 to 14:1, reaction time (from 30 to 160min), and reaction temperature (between 60 and 110 degrees C). The succinylated cellulosic derivatives were prepared with a low degree of substitution (DS) ranging from 0.071 to 0.22. The results showed that the increase of reaction temperature, molar ratio of SA/AGU in cellulose, and reaction time led to an increase in DS of cellulose samples. The products were characterized by FT-IR and solid-state CP/MAS (13)C NMR spectroscopy, and thermal analysis. It was found that the crystallinity of the cellulose was completely disrupted in the ionic liquid system under the conditions given. The data also demonstrated that homogeneous modification of cellulose with succinic anhydride in AmimCl resulted in the production of cellulosic monoester. The thermal stability of the succinylated cellulose decreased upon chemical modification.

In this study, we investigated the physicochemical properties of the cellulosic preparations obtained from both untreated perennial ryegrass leaves and de-juiced leaves. It was found that treatment at 22 degrees C with 18% NaOH and 18% KOH for 2h, and 10% NaOH and 10% KOH for 16 h yielded 28.2%, 28.8%, 22.7%, 23.4%, respectively, of 'cellulose' residue from untreated ryegrass leaves and 35.7%, 36.8%, 32.8% and 34.6%, respectively, from the de-juiced leaves. For each cellulosic fraction, the glucose content was 71.6%, 69.6%, 67.8%, 66.7%, 69.7%, 68.6%, 63.9% and 61.7%, respectively. The structure of the cellulose samples was examined using FTIR and CP/MAS (13)C NMR spectroscopy and X-ray diffraction. The cellulosic preparations were free of bound lignin except for noticeable amounts of residual hemicelluloses (28.4-38.3%), and had intrinsic viscosities between 275.1 and 361.0 mL/g, along with molecular weights from 144,130 to 194,930 g/mol. This study found that the cellulose samples isolated from both de-juiced ryegrass leaves and the untreated leaves had a much lower percent crystallinity (33.0-38.6%) than that from wood-based fibres (60-70%) and had much shorter fibres (0.35-0.49 mm) than those of either cereal straws, bagasse or wood. In addition, a partial disruption of the hydrogen bonds and microfibrils may occur during the de-juicing process by mechanical activity, which results in a decreased cellulose crystallinity and fibre length. These findings are significant in relation to hydrolysing ryegrass cellulose for bio-ethanol production.

Fully bleached softwood kraft pulps were hydrolyzed with cellulase (1,4-(1,3:1,4)-beta-D-glucan 4-glucano-hydrolase, EC 3.2.1.4) from Trichoderma reesei. Supra-molecular structural features of cellulose during enzymatic hydrolysis were examined by using CP/MAS 13C NMR spectra in combination with line-fitting analysis. Different types of cellulose allomorphs (cellulose I(alpha), cellulose I(beta), para-crystalline) and amorphous regions were hydrolyzed to a different extent by the enzyme used. Also observed was a rapid initial phase for hydrolysis of regions followed by a slow hydrolysis phase. Cellulose I(alpha), para-crystalline, and non-crystalline regions of cellulose are more susceptible to enzymatic hydrolysis than cellulose I(beta) during the initial phase. After the initial phase, all the regions are then similarly susceptible to enzymatic hydrolysis.

The nature of water sorption to different materials has always been a complex matter to address, partly due to the different possibilities of hydrogen-bond formation. For cellulosic materials this is extremely important for its product performance. In order to gain a deeper understanding of the moisture adsorption mechanisms of cellulose and hemicelluloses, the molecular interaction between moisture and paper and between moisture and some wood polymers was studied using FTIR spectroscopy under stable humid conditions. It was found that all the moisture-sorbing sites adsorbed moisture to the same relative degree, and that the rate of adsorption was the same for all these sites. It was also noticed that the moisture is adsorbed in the form of clusters. A direct relationship was found between the moisture weight gain and the increase in the absorbance peaks for humidities up to 50% relative humidity after which the moisture gain increased faster, a fact that still remains to be explained.

The cellulose structure is a factor of major importance for the strength properties of wood pulp fibers. The ability to characterize small differences in the crystalline structures of cellulose from fibers of different origins is thus highly important. In this work, dynamic FT-IR spectroscopy has been further explored as a method sensitive to cellulose structure variations. Using a model system of two different celluloses, the relation between spectral information and the relative cellulose Ialpha content was investigated. This relation was then used to determine the relative cellulose Ialpha content in different pulps. The estimated cellulose I allomorph compositions were found to be reasonable for both unbleached and bleached chemical pulps. In addition, it was found that the dynamic FT-IR spectroscopy technique had the potential to indicate possible correlation field splitting peaks of cellulose Ibeta.

Partially depolymerized, water-soluble hemicelluloses were solubilized from flax shive employing hydrothermal microwave treatment and thereafter subjected to ion-exchange chromatography, enzymatic purification and/or size-exclusion chromatography (SEC). The oligo- and polysaccharide fractions thus obtained were characterized with respect to molar mass, molar mass distribution, degree of polymerization (DP) and degree of substitution with acetyl moieties (DSAc) by employing SEC in combination with MALDI-TOF mass spectrometry. The major portion of the water-soluble flax hemicellulose consisted of an O-acetyl-4-O-methylglucuronoxylan exhibiting a DPp value (i.e., peak-average DP) of 28. When the DSAc for this O-acetyl-4-O-methylglucuronoxylan was calculated on the basis of the MALDI-MS spectra obtained without and following deacetylation, a value of 0.7 was obtained. In addition, an O-acetyl-glucomannan (DPp=9, DS=0.4) and minor quantities of small neutral O-acetyl-xylooligosaccharides were also isolated from the mixture of water-soluble hemicelluloses released from the flax shive by microwave treatment.

O-acetylated glucomannans were isolated from aspen and birch wood employing two different procedures and thereafter subjected to carbohydrate analysis by NMR spectroscopy and MALDI mass spectrometry. In one of the isolation procedures, acetone-extracted aspen or birch wood meal was extracted with dimethyl sulfoxide and then with hot water. Fractionation of the hemicellulose-containing extracts by size-exclusion chromatography was subsequently performed. In the other procedure, fractional precipitation with ethanol was used to isolate glucomannans from lyophilized process water produced by mechanical pulping of aspen. The aspen and birch glucomannans are O-acetylated at the C-2 or C-3 position of some of the mannose residues (random distribution), with a degree of acetylation of approx 0.3. In both cases the degree of polymerization was approx 16, indicating that low-molecular mass fractions of the glucomannans in hardwood have been isolated here.

Partly depolymerized hemicelluloses isolated from wood chips of spruce and aspen employing microwave treatment were resolved using size-exclusion chromatography (SEC) into oligo- and polysaccharide fractions containing components with a narrow range of sizes, as determined by MALDI mass spectroscopy. The degree of substitution with acetyl moieties (DS) was also calculated on the basis of the MALDI-MS spectra obtained prior to and following deacetylation. For spruce hemicelluloses, the low molecular mass fraction contained small arabino-4-O-methylglucuronoxylan oligosaccharides, with DP values ranging from 4 to approximately 20, separated primarily on the basis of their charge density. The fraction eluted last consisted of an O-acetyl-(galacto)glucomannan polysaccharide of peak-average DP value (DP(p)) 14. The degree of substitution with acetyl groups (DS) decreased with decreasing DP, a value DS of 0.39 being obtained for the fraction with DP(p) 12. For the aspen hemicelluloses, the SEC fractions eluted first contained an acidic O-acetyl-4-O-methylglucuronoxylan polysaccharide with DP ranging from 10 to approximately 28 and an average DS of approximately 0.75. The fractions eluted last consisted of oligosaccharide mixtures composed primarily of small neutral O-acetyl-xylooligosaccharides (DP(p) 6, DS 0.41), together with minor quantities of an O-acetyl-glucomannan.

The structures of water-soluble birch and beech xylans, extracted from holocellulose using dimethyl sulfoxide, were determined employing 1H and 13C NMR spectroscopy together with chemical analysis. These polysaccharides were found to be O-acetyl-(4-O-methylglucurono)xylans containing one 4-O-methylglucuronic acid substituent for approximately every 15 D-xylose residues. The average degree of acetylation of the xylose residues in these polymers was 0.4. The presence of the structural element -->4)[4-O-Me-alpha-D-GlcpA-(1-->2)][3-O-Ac]-beta-D-Xylp-(1--> was demonstrated. Additional acetyl groups were present as substituents at C-2 and/or C-3 of the xylopyranosyl residues. Utilizing size-exclusion chromatography in combination with mass spectroscopy, the weight-average molar masses (and polydispersities) were shown to be 8000 (1.09) and 11,100 (1.08) for birch and beech xylan, respectively.

Sulfated beta-(1-->4)-galacto-oligosaccharides were prepared from an arabino-galacto-rhamno-galacturonan from Lupinus polyphyllus Lindl. by successive partial hydrolysis and SO3-pyridine sulfation in DMF. The resulting oligosaccharide polysulfates were analyzed by analytical GPC and the sulfate content was determined by ion chromatography. DP 5 and higher showed a pronounced antiangiogenic effect with scores of 0.9-1.2 for DP 7-9 using the CAM-assay. An interaction with the fibroblast growth factor FGF-2 was noticed for DP 4-12 depending on the degree of sulfation using the FGF-2-trypsin assay.

Water-soluble hemicelluloses were extracted from milled aspen wood (Populus tremula) employing microwave oven treatment at 180 degrees C for 10 min. The final pH of this extract was 3.5. From this extract oligo- and polysaccharides were isolated and subsequently fractionated by size-exclusion chromatography. The structures of the saccharides in three of the fractions obtained were determined by 1H and 13C NMR spectroscopy, using homonuclear and heteronuclear two-dimensional techniques. The polysaccharides present in the two fractions eluted first were O-acetyl-(4-O-methylglucurono)xylans. The average degree of acetylation of the xylose residues in these compounds was 0.6. The structural element -->4)[4-O-Me-alpha-D-GlcpA-(1-->2)][3-O-Ac]-beta-D-Xylp-(1 --> could also be identified. On the average, these two xylans were composed of the following (1-->4)-linked beta-D-xylopyranosyl structural elements: unsubstituted (50 mol%), 2-O-acetylated (13 mol%), 3-O-acetylated (21 mol%), 2,3-di-O-acetylated (6 mol%) and [MeGlcA alpha-(1-->2)][3-O-acetylated] (10 mol%). Most of the 4-O-methylglucuronyl and acetyl substituents in the isolated polysaccharides survived the microwave oven treatment. The third fraction, eluted last, contained acetylated xylo-oligosaccharides, with minor contamination by an acetylated mannan. In the case of these xylo-oligosaccharides, the average degree of acetylation was 0.3.

Neutral and acidic oligosaccharides were obtained from an unbleached birch kraft pulp by treatment with a Trichoderma reesei endoxylanase pI 9 and subsequently characterized using capillary zone electrophoresis (CZE) and matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). The borate complexes of unsaturated acidic oligosaccharides having a 4-deoxy-beta-L-threo-hex-4-enopyranosyluronic acid (4 delta UA) residue linked to a beta-D-(1-->4)-xylooligosaccharide backbone were separated by CZE and detected by their UV absorption at 232 nm without prior derivatization. Pre-column derivatization with the chromophore 6-aminoquinoline (6-AQ) followed by CZE in alkaline borate buffer using detection based on absorption at 245 nm was used in the case of neutral xylosaccharides. Furthermore, MALDI-TOF-MS was employed to determine the molecular masses of both unsaturated and saturated acidic oligosaccharides. The acidic oligosaccharides released upon endoxylanase treatment of the birch kraft pulp were a (4 delta UA)-beta-D-xylotetraose, a (4 delta UA)-beta-D-xylopentaose, a (4-O-methyl-alpha-D-glucurono)-beta-D-xylotetraose, and a (4-O-methyl-alpha-D-glucurono)-beta-D-xylopentaose. Analysis after enzymatic hydrolysis with beta-xylosidase and alpha-glucuronidase from Trichoderma reesei strongly indicated that the uronic acid residue in these acidic oligosaccharides was linked to the D-xylose unit adjacent to the non-reducing D-xylose unit. The neutral xylosaccharides obtained after endoxylanase treatment of the pulp sample were D-xylose, beta-(1-4)-D-xylobiose and beta-(1-4)-D-xylotriose.