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Fluorescence labeling with N -(1-naphthyl)ethylenediamine is highly effective for quantifying oxidized reducing end groups (REGs) in cellulosic materials. When combined with size exclusion chromatography in DMAc/LiCl, along with fluorescence / multiple-angle laser light scattering / refractive index detection, a detailed profile of C1-oxidized REGs relative to the molecular weight distribution of the cellulosic material can be obtained. In this work, the derivatization process was extensively optimized, to be carried out heterogeneously in the solvent N -methyl-2-pyrrolidone. Furthermore, we show that to achieve high selectivity for carboxyl groups at the C1 position, keto and aldehyde groups need to be selectively reduced (e.g., by NaBH 4), and carboxyl groups other than at C1 need to be blocked (e.g., by methylation with (trimethylsilyl)diazomethane) prior to fluorescence labeling of carboxyl groups at C1 position. Finally, we demonstrate the practical value of the analytical method by measuring the content of the C1-oxidized REGs in cellulose samples after chemical (by Pinnick oxidation) or enzymatic (by treatment with C1-oxidizing LPMO enzymes) oxidation of various pulp samples. [Display omitted] [ABSTRACT FROM AUTHOR]

The deconstruction and valorization of chitinous biomass from crustaceans is a promising route for sustainable bioproduct development alternative to petroleum-based materials. However, chitin nanocrystal and chitin nanofibril isolation from crustacean shells is often subjected to extensive processing, compromising their environmental and cost sustainability. To address the sustainability challenge that chitin valorization presents, herein we introduce a mild fibrillation route to generate "chitin pulp"; where a careful control of the macro- and micro-fibrillated chitin with protein and mineral components yields tailored properties. Films produced from protein-rich chitin pulp showed ultimate strength of up to 93 ± 7 MPa. The surface energy and wetting behavior, going from hydrophilic to nearly-hydrophobic, could be tailored as a function of pulp composition. Life cycle assessment of the protein-rich chitin pulps demonstrated that the global warming potential of chitin pulp is reduced by 2 to 3 times when compared to chitin nanocrystals. Overall, this work presents a new and potentially scalable route for the generation of chitin-based materials having a reduced environmental footprint compared to nanochitins and chitosan, thus opening a new route for the valorization of chitin beyond nanochitin for the development of environmentally and economically sustainable materials. [Display omitted] [ABSTRACT FROM AUTHOR]

To investigate the polysaccharides of cubiu ( Solanum sessiliflorum D.) fruits, pulp and peel were subjected to sequential extractions using different solvents, giving rise to pectins heterogeneous with respect to their structural characteristics, xylan, arabinogalactoxyloglucans and glucomannans. Chemical, physicochemical and spectroscopic analyses were used to characterize the polysaccharides obtained. Pectins with uronic acid content of commercial grade were obtained from the peel of cubiu fruits using water (25 °C and 100 °C) and EDTA and from its pulp using water (100 °C). The fraction with the highest yield (9.6%) and uronic acid content (79.0%) extracted from the peel using water at 100 °C was chemically and structurally characterized. This fraction consists predominantly of a mixture of a homogalacturonan (degree of methyl-esterification 56.9%) and a small amount of rhamnogalacturonan I branched by type I and type II arabinogalactans. The results suggest that cubiu is a promising source of pectins with high uronic acid content extractable by cheaper and environmentally friendly method. [ABSTRACT FROM AUTHOR]

Cellulose, the major component of secondary cell walls, is the most abundant renewable long-chain polymer on earth. Nanocellulose has become a prominent nano-reinforcement agent for polymer matrices in various industries. We report the generation of transgenic hybrid poplar overexpressing the Arabidopsis gibberellin 20-oxidase1 gene driven by a xylem-specific promoter to increase gibberellin (GA) biosynthesis in wood. X-ray diffraction (XRD) and sum frequency generation spectroscopic (SFG) analyses showed that cellulose in transgenic trees was less crystalline, but the crystal size was larger. The nanocellulose fibrils prepared from transgenic wood had an increased size compared to those from wild type. When such fibrils were used as a reinforcing agent in sheet paper preparation, the mechanical strength of the paper was significantly enhanced. Engineering the GA pathway can therefore affect nanocellulose properties, providing a new strategy for expanding nanocellulose applications. [ABSTRACT FROM AUTHOR]

Nanocellulose was successfully isolated from Gelidium elegans red algae marine biomass. The red algae fiber was treated in three stages namely alkalization, bleaching treatment and acid hydrolysis treatment. Morphological analysis was performed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). TEM results revealed that the isolated nanocellulose had the average diameter and length of 21.8 ± 11.1 nm and of 547.3 ± 23.7 nm, respectively. Fourier transform infrared (FTIR) spectroscopy proved that the non-cellulosic polysaccharides components were progressively removed during the chemically treatment, and the final derived materials composed of cellulose parent molecular structure. X-ray diffraction (XRD) study showed that the crystallinity of yielded product had been improved after each successive treatments subjected to the treated fiber. The prepared nano-dimensional cellulose demonstrated a network-like structure with higher crystallinity (73%) than that of untreated fiber (33%), and possessed of good thermal stability which is suitable for nanocomposite material. [ABSTRACT FROM AUTHOR]

The study investigated the feasibility of co-production of nanocellulose crystal (CNC) and ethanol using the bleached pine kraft pulp (BPKP) as a substrate by enzymatic hydrolysis. An engineering strain Penicillum oxalicum cEES-XM was constructed to produce suitable cellulase used in enzymatic hydrolysis of BPKP for preparing CNC. The cellulase from Trichoderma reesei SCB18 was used for simultaneous saccharification and fermentation of residues and hydrolysates from enzymatic hydrolysis for producing ethanol. The result showed that the CNC yield reached 7.35 % (w/w) by hydrolysis at 10 % solid content, and the final ethanol concentration was 13.27 mg/mL in fermentation liquor. Using SEM, XRD, TGA, and DLS methods, the characteristics of CNC including, morphology, crystallinity, thermal stability and particle size distribution, were also examined. This work provided a reference for realizing high-efficient application of cellulose in the pulp. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: In this work, highly accessible cellulose microfibers produced from kraft wood pulp by a novel method based on a single mechanical treatment with a wet stirred media mill were characterized. The high mechanical stress of milling resulted in the complete disintegration of the fiber cell wall and produced cellulose microfibers with a length of below 50μm and diameter ranging from a few hundred nanometers to 1μm after only 5min of milling. The noticeable increase in BET (Brunauer, Emmett, Teller-method) surface area from the initial value of 2.2m2/g to 25–60m2/g and decrease in crystallinity index from 65% to 20–30% during milling (5–60min) indicated that microfibers possessed a highly accessible surface area and a large number of amorphous sites. This was also supported by the significantly increased reactivity of the microfibers compared to the reference pulp in the periodate oxidation reaction of cellulose to dialdehyde cellulose. [ABSTRACT FROM AUTHOR]

Abstract: The composition of cell wall polysaccharides of pitaya (Hylocereus sp.) fruit pulp was studied with the aim of designing proper maceration processes for the fruit processing industry. Therefore, the degree of esterification of pectin was determined through a potentiometric titration and the consistency with a Bostwick consistometer. Moreover, the alcohol insoluble residue (AIR) was extracted and subsequently fractionated into water-, oxalate-, acid- and alkali-soluble pectins, hemicellulose and cellulose. Each fraction was analyzed for its neutral sugar composition by gas chromatography. Additionally, the AIR uronic content was measured by the m-hydroxydiphenyl (MHDP) assay. Pectin fractions in the analyzed fruit pulp were composed mainly of arabinose and galactose, while the hemicellulose fraction consists mainly of glucose, xylose and galactose. Considering the limited uronic acid content (32.3%) in the AIR and the high esterification degree of pectin, the high viscous consistency of this fruit pulp might not be highly attributed to pectin fractions. [Copyright &y& Elsevier]

Abstract: The soda pulping of brewer''s spent grain (BSG) pretreated with dilute-acid was studied. A first-order full-factorial design was used to evaluate the effect of the operational variables: soda concentration (1–2%), temperature (80–120°C) and pulping time (30–90min), on the properties of the pulp (cellulose and lignin contents) obtained from BSG. The factorial design permitted to identify the optimum operating conditions for BSG soda pulping. Equations relating the responses (properties of the pulp) to the operational variables were thus proposed, and fitted the experimental results at 99 and 90% confidence levels, for the cellulose and lignin contents, respectively. The best pulping conditions (2% soda concentration, 120°C, 90min) led to a pulp containing 72.1% w/w cellulose and low residual lignin content (10.4% w/w). [Copyright &y& Elsevier]

Abstract: Extraction of peeled fruits of Opuntia ficus indica afforded with 3.8% yield a mucilage, which contained 23.4% of galacturonic acid. Total hydrolysis of a mucilage and gas–liquid chromatographic analysis of the derived alditol acetates indicated the presence of arabinose, rhamnose, xylose and galactose in the molar ratio 1.0:1.7:2.5:4.1. Gel permeation chromatography on Sepharose CL-4B showed the polysaccharide to be composed of at least five fractions. Treatment with cetrimide allowed the separation of an insoluble fraction (44.3% yield), which contained 28.0% of uronic acid. This fraction contained xylose, rhamnose and galactose in the molar ratio 1.0:2.5:2.8. The fraction soluble in cetrimide (15.6% yield) contained 16.0% uronic acid, and arabinose and galactose in the molar ratio of 1:2.2. It is composed of two main subfractions as shown by gel permeation chromatography. These results indicate that the mucilage from fruits O. ficus indica is a complex mixture of polysaccharides, less than 50% corresponding to a pectin-like polysaccharide. [Copyright &y& Elsevier]

The efficiency of acid methanolysis toward cleavage of glucuronosyl linkages in hemicelluloses and pectins was studied. Two aldo-uronic acids (a dimer and a tetramer) were submitted to methanolysis with different acidic strength and methanolysis time. The aldo-uronic acid tetramer was only affected by the acidity of the medium, whereas the dimer was sensitive towards both reaction time and acidity. It was concluded that methanolysis of 0.5–1 mg of model compounds with 2 ml of 2 M HCl/MeOH at 100°C for 3–5 h was the best compromise between good cleavage of the glucuronosyl bonds (≈70%, mol/mol) and little degradation of the uronic acid released (below 20%, mol/mol). The acid methanolysis of reference oligo- and polysaccharides verified the good accuracy of the method. The application of acid methanolysis on mechanical pulp fibres was tested on a thermomechanical pulp. [Copyright &y& Elsevier]

• Cellulose-based solutions can improve environmental performance of food packaging. • Food products require specific barrier functions from cellulose-based packaging. • Eco-design enables quantifying environmental performance and identifying trade-offs. • Fulfilling the barrier requirements for food product packaging is crucial. This short communication describes the climate change impacts of using cellulose, and more precisely cellulosic fiber-based materials, in food packaging, representing current and emerging industrial state of the art technology, without specific reference to current scientific advances. First, the different types of cellulosic fiber-based packaging materials, which can be used to replace fossil-based packaging materials, are presented for flexible and rigid applications. The focus is on technological solutions with packaging properties that enable the protection of commonly sold food products. The manufacturing processes associated with these cellulosic fiber-based materials is described and the environmental impact assessment of 4 selected case studies presented: stand-up pouches, flexible flow wraps, frozen or chilled food trays, and molded pulp lids. A simplified eco-design Life Cycle Assessment (LCA) was then performed to compare each solution with its fossil-based counterpart. Differences and similarities between the various cellulosic solutions have been identified. Furthermore, the assessment confirms that cellulosic fiber-based materials have reduced environmental impacts as compared to fossil-based counterparts, if a similar packaging weight is obtained. Indeed, all impacts of plastics are between 3 and 5 kg CO 2 eq/kg, while all impacts of cellulosic fiber-based materials are below 1.5 kg CO 2 eq/kg. [ABSTRACT FROM AUTHOR]

• Residual nitrogen in cellulosics comes from bound amines from processing or washing. • The bound amines originate, e.g., from cellulose solvents, swelling agents or enzymes. • 2,5-Dihydroxy-[1,4]-benzoquinone (DHBQ) is a cellulose key chromophore formed upon aging. • DHBQ has a high affinity to amines and binds them covalently. • DHBQ is a major cause of nitrogen fixation in aged cellulosics. • There is a direct, linear relationship between formed DHBQ and bound amine traces. Cellulosic material is capable of permanently retaining nitrogen compounds (mostly having amino functions), which is reflected in a residual nitrogen content (in the low per mille range to the low percent range) of some pulps and certain lab samples. Merely adsorptively bound compounds can be removed by mild acidic washing, but part of the nitrogen seems to be resistant and very tightly bound, and thus not accessible for removal by washing. Tertiary and aromatic amines are not retained in this way, but only primary and secondary amines. There is only a weak correlation between the "firmly bound nitrogen" and the carbonyl content in cellulosics (because of oxidative damage), so that possible aminal, Schiff base and enamine structures can hardly be relevant as major nitrogen sources. However, there is a very good linear correlation between the ISO brightness (chromophore content) in aged pulps and the residual nitrogen content. In particular the concentration of the cellulosic key chromophore 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) determines the permanent N -binding capacity of the pulp. DHBQ reacts very readily with primary and secondary amines under ambient conditions to 2,5-diamino-substituted [1,4]-benzoquinones, which have very low solubility (because of zwitterionic resonance contributions) and thus remain on/in the pulp. Examples of nitrogen fixation in pulps are the binding of piperidine (a common amine catalyst in derivatization reactions), amine degradation products of the cellulose solvent NMMO, dimethylamine in materials processed from the cellulose solvent DMAc/LiCl, imidazole (a degradation product of 1-alkyl-3-methylimidazolium ionic liquids), and of amino groups in proteins after enzymatic treatment. The nature of the respective DHBQ-amine addition compound has been verified by complete structure determination. [ABSTRACT FROM AUTHOR]