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The first goal of this study was to determine the polysaccharide composition of Pinus brutia wood and how this composition changes during kraft pulping. The second goal was to determine the effect of the stem height on chemical composition. The content of hemicelluloses was about 280 mg/g at a height of 1.3 m, whereas the content was about 300 mg/g at the top of the stem (4.3 m). The main sugars in the wood of P. brutia were mannose (102 mg/g dw), xylose (69 mg/g dw), and glucose (44 mg/g dw). During kraft pulping, 52% of the total hemicelluloses were degraded. Glucose and xylose were more stable than mannose. The total amounts of cellulose in the wood and in the kraft pulp of P. brutia were determined to be 330 mg/g and 661 mg/g, respectively, at 1.3 m. [ABSTRACT FROM AUTHOR]

Background: In the production of biofuels from lignocellulosic material, biocrude plays a key role. The present work deals with the biocrude production through hydrothermal liquefaction (HTL) of birch wood in supercritical ethanol over 5 wt% Fe‐H‐Beta‐150 (SiO2 to Al2O3 ratio of 150) or 5 wt% Fe‐SiO2 catalyst. Results: The liquid and solid products were characterized with various analytical techniques such as gas chromatography mass spectrometry (GC–MS), gas chromatography with a flame ionization detector (GC‐FID), size exclusion chromatography (SEC), inductively‐coupled plasma mass spectrometry (ICP‐MS), powder X‐ray diffraction (p‐XRD), scanning electron microscopy (SEM), and solid‐state carbon‐13 magic angle spinning nuclear magnetic resonance (13C‐MAS‐NMR), respectively. The results revealed that 5 wt% Fe‐H‐Beta‐150, a strongly Brønsted acidic catalyst, enhanced the biocrude formation when compared with a non‐acidic 5 wt% Fe‐SiO2 catalyst. Hemicellulose and lignin degradation occurred resulting in formation of mainly sugars, acids‐esters and phenolic compounds in the liquid phase. The gaseous atmosphere of hydrogen also enhanced the degradation of biomass. The biocrude yield from birch was 25 wt% over 5 wt% Fe‐H‐Beta‐150. The Brønsted acidic catalyst gave higher dissolution efficiency and its clear catalytic effect was observed in comparison to non‐acidic 5 wt% Fe‐SiO2. The degradation level of lignin in the presence of 5 wt% Fe‐H‐Beta‐150 was high 68 wt% aromatic products were formed, while only 38 wt% was obtained with 5 wt% Fe‐SiO2. Conclusions: Hydrogen atmosphere enhances the fractionation of birch wood when compared to argon atmosphere. The 5 wt% Fe‐H‐Beta‐150 catalyst enhanced very strongly the degradation of hemicellulose and lignin in biomass to sugars and acid‐esters as well as phenolic compounds, respectively, compared to the non‐acidic 5 wt% Fe‐SiO2 catalyst. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Hemicellulose O-acetyl-galactoglucomannan (GGM) is the main noncellulosic water-soluble polysaccharide in the coniferous softwood Norway spruce, consisting of anhydro-galactose, -glucose, and -mannose. Acid hydrolysis of GGM has been studied in a continuous tube reactor to obtain these sugars under industrially relevant conditions. The reaction was performed under atmospheric pressure at 90°C and 95°C, and hydrochloric acid (HCl) served as catalyst. The influence of the reaction parameters, such as acid concentration (pH), temperature, concentration of the substrate, as well as catalyst and reactant flow rates, has been studied on the conversion efficiency and product distribution. Continuous production of monomeric sugars was achieved without formation of low-molecular by-products. The GGM conversion was high with HCl as catalyst, at 95°C, and a pH of 0.3. The main hydrolysis products were mannose, glucose, and galactose monomers. Minor amounts of sugar dimers were detected among the products. The experimental results are described with a laminar flow model for the continuous reactor. [ABSTRACT FROM AUTHOR]

Various lignin determination methods have been applied to hemicellulose-rich wood extracts obtained after pressurized hot-water extraction (PHWE) and membrane ultrafiltration (UF). In focus were the chlorine number (Cl no.) method, the acetyl bromide method, and the four modifications of the Klason lignin determination, such as the KCL, TAPPI, LAP, and Goldschmid methods. The furfural (F) and hydroxymethylfurfural (HMF) concentrations in the acid hydrolysates were also determined. The mass balances of the fraction were calculated with respect to the contents of dry solids and lignin, including the acid-soluble lignin. The reliability of the methods was evaluated based on the lignin mass balances and the gross chemical composition of the extracts. Although the results were dependent on the method applied, the lignin mass balance calculations yielded similar results in general. [ABSTRACT FROM AUTHOR]

A major enhancement of grease and water vapor barrier properties was accomplished with a 1-10 g/m coating of O-acetyl galactoglucomannan (GGM) ester or with GGM coatings applied as water dispersions on cartonboard. GGMs were esterified with phthalic and benzoic anhydrides, respectively. The novel phthalic esters of GGM (GGM-Ph) were characterized with HPLC, NMR, and matrix-assisted laser desorption/ionization with mass spectrometry (MALDI-TOF-MS). The degree of substitution of GGM-Ph was obtained by H NMR, C NMR, and HPLC. The GGM esters and GGM were coated onto cartonboard, and they demonstrated good moisture and very good grease resistance even with thin 1-3 g/m coatings. The time for penetration of 0.1 % rapeseed oil was 54 h with the 2.4 g/m coating thickness. The lowest water vapor transmission value was 39 g/m/24 h with 9.7 g/m coating. The GGM esters had clearly higher water resistance and slightly higher grease barrier values than native GGM. High-molar-mass-based GGM (50 kg/mol) and GGM-Ph rendered better water vapor and grease barrier properties than low-molar-mass GGM (9 kg/mol) and GGM-Ph. The GGM-based coatings can be safely used on an industrial scale as water was used as a solvent. As obtained from non-food-based side-stream wood-based resources, GGM and GGM esters project a sustainable and modern conception for barrier purposes in food packaging. [ABSTRACT FROM AUTHOR]

The production of biofuels and other chemicals from lignocellulosic biomass is limited by the inefficiency of enzymatic hydrolysis. Here a biomimetic composite material consisting of bacterial cellulose and wood-based hemicelluloses was used to study the effects of hemicelluloses on the enzymatic hydrolysis with a commercial cellulase mixture. Bacterial cellulose synthesized in the presence of hemicelluloses, especially xylan, was found to be more susceptible to enzymatic hydrolysis than hemicellulose-free bacterial cellulose. The reason for the easier hydrolysis could be related to the nanoscale structure of the substrate, particularly the packing of cellulose microfibrils into ribbons or bundles. In addition, small-angle X-ray scattering was used to show that the average nanoscale morphology of bacterial cellulose remained unchanged during the enzymatic hydrolysis. The reported easier enzymatic hydrolysis of bacterial cellulose produced in the presence of wood-based xylan offers new insights to overcome biomass recalcitrance through genetic engineering. [ABSTRACT FROM AUTHOR]

Highlights • Hemicelluloses were obtained via alternative wood biorefining strategies. • Hemicelluloses were compared as biobased emulsion stabilizers. • Sustainable alkyd paint emulsions were characterized. • Natural hemicellulose-rich isolates showed promising functionality. • The crude technical hemicellulose fractions were the most efficient stabilizers. Abstract Wood biorefining currently involves large-scale industrial processes where a notable portion of raw materials, namely hemicelluloses and lignin, are either lost with the process water, degraded, or burnt for energy. Value-added utilization of polymeric hemicelluloses is challenging due to their intermediate molar mass and the presence of other wood components, such as phenolic residues or wood extractives. Oil-in-water (O/W) emulsions represent a diverse and abundant class of applications in which the natural properties of wood hemicelluloses are beneficial. In the current work, we present highly promising new technical alkyd paint emulsion systems stabilized with hardwood glucuronoxylans (GX) and softwood galactoglucomannans (GGM). Samples from three isolation methods and their further fractionation by ethanol precipitation were systematically compared with regard to hemicellulose composition, interfacial activity, and functionality in emulsions. Emulsification of alkyd resins was successful with both GX and GGM obtained by various biorefining strategies. The highest emulsion stability over storage was achieved using crude non-purified GX and GGM fractions, and was correlated with the presence of phenolic compounds and extractives, interfacial activity, and small droplet size. Hardwood GX and softwood GGM are envisioned as natural emulsifiers of alkyd O/W emulsions, which are examples of diverse and abundantly-used technical dispersions. This study can be utilized as a guideline for targeted extraction of hemicelluloses with desired functionality, and as a protocol for developing environmentally-compatible industrial dispersions. [ABSTRACT FROM AUTHOR]

Hemicelluloses, the second most abundant polysaccharide right after cellulose, are in practice still treated as a side-stream in biomass processing industries. In the present study, we report an approach to use a wood-derived and side-stream biopolymer, spruce wood hemicellulose (galactoglucomannan, GGM) to partially replace the synthetic PLA as feedstock material in 3D printing. A solvent blending approach was developed to ensure the even distribution of the formed binary biocomposites. The blends of hemicellulose and PLA with varied ratio up to 25% of hemicellulose were extruded into filaments by hot melt extrusion. 3D scaffold prototypes were successfully printed from the composite filaments by fused deposition modeling 3D printing. Combining with 3D printing technique, the biocompatible and biodegradable feature of spruce wood hemicellulose into the composite scaffolds would potentially boost this new composite material in various biomedical applications such as tissue engineering and drug-eluting scaffolds. [ABSTRACT FROM AUTHOR]

The influence of oxygen (0–50 bar) on the molar mass and composition of hemicelluloses after hydrothermal treatment of spruce chips was studied in a batch reactor setup at 130 °C–160 °C. Purified galactoglucomannan was studied as a reference. The dissolved oxygen enhanced significantly the depolymerization of hemicelluloses from over 15,000 g/mol to 180 g/mol (monomers) as well as promoted acids formation from the monosaccharides. About 2–3 times faster depolymerization was observed already with rather low amounts of oxygen (2–8 bar), while the kinetics of depolymerization was significantly slower in inert atmosphere. The decrease in pH from neutral to as low as 2.5 lead to an autocatalytic effect on the polysaccharide hydrolysis and the consecutive reactions of monosaccharides. The results emphasize the importance of performing hydrothermal treatment under inert atmosphere if large polymeric hemicellulsoses are desired or if monosaccharides are targeted in hydrolysis of hemicelluloses. If autocatalysis begins, it is difficult to stop. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: 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 0.05M 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 &y& Elsevier]