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The cell walls of cereals are rich sources of polysaccharide β-glucan. In this study, the β-glucan was extracted from oat bran using the hot-water extraction method and dried in a pure powder form. The concentration of the β-glucan in the extract was determined using the l-cysteine sulfuric acid method. The results showed that the yield of β-glucan using the hot-water extraction method is the highest compared to its yield achieved by enzymatic, acid, and alkaline methods. In this paper, the usage of the β-glucan as a coating material for a water-insoluble carotenoid is considered. This study demonstrates for the first time the encapsulation of β-carotene with modified octanoic acid β-glucan. It implements to obtain a stable encapsulated polysaccharide-carotenoid system, which has been studied by a set of physicochemical methods and a cytotoxic analysis was performed on the HCT-116 cell line. The SEM image of the resulting encapsulated system is perfectly correlated with the DLS data, which has determined the size of MG capsules at 200 nm. The cytotoxic analysis demonstrates that the cell viability was more than 70%, which indicates its potential using in the food industry. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was aimed to compare the antioxidant and cytoprotective effects of hot‐water and enzyme‐extracted constituents of Protaetia brevitarsis seulensis powder. The products of enzymatic extraction had 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH)‐radical‐scavenging activity, cytotoxic effects, and provided cytoprotection against H2O2 and intracellular reactive oxygen species. Enzymatic extraction improved DPPH‐radical‐scavenging activity relative to hot‐water extraction (P < 0.05), with inhibition rates of 33% at 500 μg/mL and 35% at 1000 μg/mL. Cell viability ranged from 100 to 122%, and was higher for hot‐water than for enzymatic extraction (P > 0.05). Hot‐water extraction achieved greater cytoprotection against H2O2 than enzymatic extraction. However, enzymatic extraction achieved greater antioxidant and cytoprotective activity against reactive oxygen species than hot‐water extraction. These results provide evidence of the antioxidant and cytoprotective effects produced by enzymatic extraction of the active ingredients from Protaetia brevitarsis seulensis powder. [ABSTRACT FROM AUTHOR]

A blend of commercial willow cultivars (Salix spp.) was subjected to hydrothermal pretreatment: hot‐water extraction in a pilot plant 65‐ft3 digester. Lignin recovered from the autohydrolyzate (willow lignin, WL) was used to produce hydrogels and thermoplastic blends. Lignin‐kaolin‐acrylamide (WL 10.7 % w/w) and lignin‐poly(ethylene)glycol diglycidyl ether (WL 66.7 % w/w) hydrogels exhibited favorable adsorption and absorption properties, respectively. Dye adsorption kinetics, swelling capacities, fragrance emanation, and compression moduli were measured for the hydrogels, along with SEM characterization. Additionally, WL was esterified by acetylation (C2, WAc) and acylation with lauroyl chloride (C12, WFAE and WFAEH). The crude and esterified lignin samples were blended (1–12 % w/w) with polylactic acid (PLA) via lab‐scale melt extrusion to produce thermoplastic blends. The physicochemical properties of the blends were evaluated. They exhibited an increase in degradation temperature and UV absorbance with potential to hinder photodegradation of PLA and may be leveraged in packaging applications. [ABSTRACT FROM AUTHOR]

The objective of the study was to investigate the water vapour sorption behaviour of thermally modified (TM) wood powder, e.g. ground wood prepared from waste streams of TM solid wood, and wood powder that was extracted in pressurised hot water. Solid spruce wood was TM in steam conditions (210°C for 3 h), milled and hot-water-extracted (HWE) at elevated pressure (140°C for 1 h). The results evidence that the hot-water extraction reduced the water sorption and the accessible hydroxyl group concentration by the removal of amorphous carbohydrates. In contrast, the enhanced cross-linking of the cell wall matrix and the annealing of amorphous matrix polymers during thermal modification reduced the sorption behaviour of wood additionally, without further reducing the hydroxyl accessibility. These additional effects of thermal modification were at least partially cancelled by hot-water extraction. The results bring novel insights into the mechanisms that reduce the water vapour sorption of wood by compositional and structural changes induced by heating. [ABSTRACT FROM AUTHOR]

Untreated and hot-water-extracted (HWE) Norway spruce (Picea abies) sawdust was cooked using the sulfur-free oxygen-alkali (OA) method under the following conditions: temperature, 170 °C; liquor-to-wood ratio, 5:1 L/kg; and NaOH charge, 19% on the oven-dry sawdust. In comparison with earlier studies conducted with birch sawdust, the spruce cooking yield data, together with the amount of the pulp rejects (78% to 86% for reference pulps from the initial feedstock and 73% to 83% for pulps from the HWE feedstock), revealed that the pretreatment stage prior to spruce OA pulping caused different effects on pulping performance. The analyses of the three main compound groups (i.e., lignin, volatile acids, and hydroxy acids) in black liquor indicated that slightly higher contents (25.5 to 45.9 g/L) of dissolved lignin were detected in black liquors originating from the HWE sawdust than in the black liquors from the reference material (27.2 to 39.6 g/L). In contrast, considerably lower (~20% decrease) volatile acid contents and similar or slightly decreased hydroxy acids contents were detected in the black liquors from the HWE sawdust.

Agricultural residues, such as corn stover, wheat straw, and nut shells show promise as feedstocks for lignocellulosic biorefinery due to their relatively high polysaccharide content and low or no nutritional value for human consumption. Apricot pit shells (APS) were studied in this work to assess their potential for use in a biorefinery. Hot water extraction (HWE; 160 °C, 2 h), proposed to remove easily accessible hemicelluloses, was performed to evaluate the susceptibility of APS to this mild pretreatment process. The chemical composition of APS before and after HWE (EAPS) was analyzed by standard methods and 1H-NMR. A low yield of the remaining HW-extracted APS (~59%) indicated that APS are highly susceptible to this pretreatment method. 1H-NMR analysis of EAPS revealed that ~77% of xylan present in raw APS was removed along with ~24% of lignin. The energy of combustion of APS was measured before and after HWE showing a slight increase due to HWE (1.61% increase). Near infrared radiation spectroscopy (NIRS), proposed as a quick non-invasive method of biomass analysis, was performed. NIRS corroborated results of traditional analysis and 1H-NMR. Determination of antioxidizing activity (AOA) of APS extracts was also undertaken. AOA of organic APS extracts were shown to be more than 20 times higher than that of a synthetic antioxidizing agent.

Lignin recovered from the hot-water extract of sugar maple (Acer saccharum) is used in this study to synthesize adhesive blends to replace phenol-formaldehyde (PF) resin. Untreated lignin is characterized by lignin content and nuclear magnetic resonance (NMR) analysis. The molecular weight distribution of the lignin and the blends are characterized by size exclusion chromatography (SEC). The effect of pH (0.3, 0.65 and 1), ex situ furfural, and curing conditions on the tensile properties of adhesive reinforced glass fibers is determined and compared to the reinforcement level of commercially available PF resin. The adhesive blend prepared at pH = 0.65 with no added furfural exhibits the highest tensile properties and meets 90% of the PF tensile strength.

Hot water extraction of aspen woodchips was treated at about 160 °C for 2 h with a liquor-to-solid ratio of 4.76:1 in a 1.84 m3 batch reactor with external liquor circulation. Both five-carbon and six-carbon sugars are obtained in the extraction liquor. Xylose and xylooligomers are the main five-carbon sugar in the hot water extract, which reached a maximum concentration of 0.016 mol/L, and 0.018 mol/L, respectively. Minor monosaccharides including galactose, mannose, rhamnose, glucose, and arabinose are also obtained during the hot water extraction. Rhamnose is the main six-carbon sugar in the extraction liquor, which has a maximum concentration of 0.0042 mol/L. The variations of acetyl groups and formic acid are investigated due to their catalytic effect on the extraction reactions. Zeroth-order kinetics models are found to be adequate in describing the dissolved solids, acids, xylose, and xylooligomers.

Abstract The thermochemical behavior of various samples of okra (Abelmoschus esculentus) and miscanthus (Miscanthus x giganteus) stalks (initial, hot-water-extracted, and those from sulfur-free delignification) were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). In all cases, major GC-amenable condensable products were measured semi-quantitatively and classified into several product groups. The formation of these product groups from different feedstock samples with varying mass portions of their structural constituents (carbohydrates and lignin) was investigated at 500 °C and 700 °C with a residence time of 5 s and 20 s. The main product groups were aliphatic compounds, such as lactone, furan, and cyclopentenone derivatives from carbohydrates (mainly hemicelluloses) and aromatic compounds, such as guaiacol, phenol, and syringol derivatives from lignin. Additionally, the formation of aliphatic and aromatic products (e.g., the ratio of aliphatic compounds to aromatic compounds) was found to be characteristically dependent on feedstock composition and pyrolysis conditions. This kind of approach is of practical importance concerning efforts not only to uncover new integrated biorefinery possibilities to manufacture value-added products but also to develop rapid characterization tools for lignocellulosics. Highlights • Solid organic fractions from hot-water-extraction of targeted non-wood feedstocks were pyrolyzed. • Fast pyrolysis has been utilized in the integrated biorefinery concept. • The ratio aliphatic/aromatic pyrolysis compounds characteristically depends on feedstock composition and pyrolysis conditions. • A basis of a rapid characterization method for lignocellulosics has been developed. [ABSTRACT FROM AUTHOR]

Wheat straw and okra stalk were studied to evaluate their potential use for integrated lignocellulosic biorefining. Besides chemical pulp, a wide spectrum of value-added by-products were prepared by hot-water extraction of the feedstocks under varying conditions (140 °C for 60 and 240 min and 150 °C for 25 and 100 min) prior to sulfur-free soda-anthraquinone (AQ) pulping (NaOH charge 15 and 20% by weight on o.d. feedstock for wheat straw and okra stalk, respectively, with an AQ charge of 0.05% by weight on o.d. for both feedstocks). During the hot-water pre-treatment, the most significant mass removal, respectively, 12% (w/w) and 23% (w/w) of the initial wheat straw and okra stalk was obtained at 150 °C with a treatment time of 100 min. The hydrolysates were characterized in terms of pH and the content of carbohydrates (6-20% (w/w) of the initial amount), volatile acids (acetic and formic acids), and furans. The pre-treatment stage also facilitated the delignification stage, and, for example, the pulp yields (w/w), 57% (145 °C, 15 min, and kappa number 18) and 41% (165 °C, 180 min, and kappa number 32) were obtained for the pre-treated (150 °C, P200) wheat straw and okra stalk, respectively. Results clearly indicated that both non-wood materials were suitable for this kind of biorefining approach. [ABSTRACT FROM AUTHOR]

A hardwood-based biorefinery process starting with hot-water extraction (HWE) is recommended in order to remove most of the hemicelluloses/xylans before further processing. HWE may be followed by delignification in acetone/water in the presence of oxygen (AWO) for the production of cellulose and lignin. In this study, the HWE-AWO sequence was evaluated for its effectiveness at removing lignin from the fast-growing species Paulownia tomentosa (PT) and Paulownia elongata (PE), in comparison with the reference species, sugar maple (Acer saccharum, SM). HWE might lead to a remarkable increase in lignin accessibility, and as a result, a greater AWO delignification degree was observed for extracted PT, PE, and SM than for unextracted ones. Organosolv lignin was recovered from the spent liquor of AWO delignification of PT with/without prior HWE and characterized to evaluate the benefits of HWE on the lignin structure and purity. The lignin recovered from the spent liquor of HWE-AWO sequence is of higher purity and lighter color than that recovered from the AWO spent liquor. These properties along with low sulfur content are desirable for lignin high-value applications.

The thermochemical behavior of birch ( Betula pendula ) sawdust both untreated and after various chemical treatments (hot-water extraction, delignification, and hot-water extraction followed by delignification) was investigated by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). In each case, major GC-amenable condensable products were classified into several compound groups, and the formation of these monomer-related fragments from feedstock samples with varying mass portions of the structural constituents (cellulose, hemicelluloses, and lignin) were determined at 500 °C and 700 °C at hold times of 5 s and 20 s. The formation of pyrolysis products was shown to be characteristically dependent on feedstock composition as well as on pyrolysis conditions. This kind of approach was of practical importance with respect to efforts not only to develop rapid characterization tools for lignocellulosics, but also to new biorefinery possibilities to produce bio-oils, for example, enriched either with aliphatic or aromatic constituents. [ABSTRACT FROM AUTHOR]

Moso bamboo (Phyllostachys edulis) is one of the widely growing bamboo species in Asia. Because of its fast growth and aggressive rhizomes, it is reported to invade other forests and reduce the biodiversity of forest ecosystems. To determine the changes in soil nutrient conditions due to moso bamboo invasion, this research measured the difference in soil labile carbon (C) and nitrogen (N) contents in a Japanese cedar (Cryptomeria japonica) forest invaded by moso bamboo in central Taiwan. The content of soluble organic C (SbOC), measured by both KCl and hot-water extraction methods, was lower in bamboo than cedar soils. This observation agreed with the finding that the more easily decomposed SbOC could be lost with bamboo invasion. In addition, both SbOCKCl and SbOCHW contents were positively correlated with microbial biomass C content, so the decreased labile organic C content in bamboo soils may reduce microbial biomass production. Principal component analysis revealed soil organic C content (total organic C, SbOC and acid-hydrolysable C) as the most important soil parameter affected by the bamboo invasion, followed by microbial biomass N and NO3 􀀀 contents in soils. The soil quality index model also agreed with the degraded soil quality with bamboo invasion. In conclusion, the invasion of moso bamboo reduced the C and N pools in bamboo soil and degraded the overall soil quality. [ABSTRACT FROM AUTHOR]

It was recently proposed that boron might be the most important nutrient structuring tree species distributions in tropical forests. Here we combine observational and experimental studies to test this hypothesis for lowland tropical forests of Panama., Plant-available boron is uniformly low in tropical forest soils of Panama and is not significantly associated with any of the > 500 species in a regional network of forest dynamics plots. Experimental manipulation of boron supply to seedlings of three tropical tree species revealed no evidence of boron deficiency or toxicity at concentrations likely to occur in tropical forest soils. Foliar boron did not correlate with soil boron along a local scale gradient of boron availability., Fifteen years of boron addition to a tropical forest increased plant-available boron by 70% but did not significantly change tree productivity or boron concentrations in live leaves, wood or leaf litter. The annual input of boron in rainfall accounts for a considerable proportion of the boron in annual litterfall and is similar to the pool of plant-available boron in the soil, and is therefore sufficient to preclude boron deficiency., We conclude that boron does not influence tree species distributions in Panama and presumably elsewhere in the lowland tropics. [ABSTRACT FROM AUTHOR]

Hot-water extraction of hemicelluloses, especially galactoglucomannans, from fractions of ground spruce wood with different particle sizes was studied at 170°C with extraction times up to 60 min. Extraction of spruce sapwood, heartwood, and thermomechanical pulp (TMP) was also compared at 160 to 180°C. Static batch extractions were carried out in an accelerated solvent extractor (ASE). The extracted hemicelluloses were characterized by sugar unit analysis and determination of acetyl groups and molar masses. The particle size significantly affected the extraction of ground wood. The total extraction yield, as well as the yields of hemicelluloses and monosaccharides, was the highest from the finest ground wood fraction (< 0.1 mm). The release of acetic acid, average molar mass of extracted hemicelluloses, and end-pH of the extracts were also dependent of the particle size, although to a lower extent. Irrespectively of the ground wood particle size, the yield of hemicelluloses reached a plateau after 40 min extraction at 170°C. The results indicate that extraction of hemicelluloses is limited mainly by the diffusion in the fiber wall, and for coarse wood shives also by the mass transfer in the wood matrix. There were only small differences in the hot-water extraction yields of hemicelluloses from spruce sapwood, heartwood, and TMP, considering both poly- and monosaccharides.

Untreated and hot-water-extracted (HWE) Norway spruce (Picea abies) sawdust was cooked using the sulfur-free oxygen-alkali (OA) method under the following conditions: temperature, 170 °C; liquor-to-wood ratio, 5:1 L/kg; and NaOH charge, 19% on the oven-dry sawdust. In comparison with earlier studies conducted with birch sawdust, the spruce cooking yield data, together with the amount of the pulp rejects (78% to 86% for reference pulps from the initial feedstock and 73% to 83% for pulps from the HWE feedstock), revealed that the pretreatment stage prior to spruce OA pulping caused different effects on pulping performance. The analyses of the three main compound groups (i.e., lignin, volatile acids, and hydroxy acids) in black liquor indicated that slightly higher contents (25.5 to 45.9 g/L) of dissolved lignin were detected in black liquors originating from the HWE sawdust than in the black liquors from the reference material (27.2 to 39.6 g/L). In contrast, considerably lower (~20% decrease) volatile acid contents and similar or slightly decreased hydroxy acids contents were detected in the black liquors from the HWE sawdust. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Southern Agriculture is the property of Journal of Southern Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pre-extraction of hemicelluloses from lignocellulosic feedstock has been a research focus during the last decade within the context of lignocellulosic biorefineries. In this study, the effect of hot-water extraction (HWE) on the topochemistry and ultrastructure of poplar wood (Populus sp.) was investigated based on scanning electron microscopy (SEM) and transmission electron microscopy (TEM) paired with immunogold labeling of the hemicelluloses. The cell walls of HWE wood (HWEW) differ significantly in their ultrastructure from neat wood, i.e., there are many distorted cells and agglomerations of lignin and extractives agglomerations in the cell lumina. Results ofimmunogold labeling indicate that different types of hemicelluloses are extracted at different stages and both their concentration and distribution within the wood cell wall layers are affected by the HWE. Hemicelluloses more closely associated with lignin appear to be more easily removed by HWE. Lignins are also extracted partially and altered. Results provide a holistic view of chemical and ultrastructural changes including the associated changes in hemicelluloses and lignin distribution in HWEW. The obtained data could be helpful to understand better the mechanical properties and adhesion related issues of HWEW for wood composite production. [ABSTRACT FROM AUTHOR]

In order to preserve the polymeric structure and the acetylation degree of extracted galactoglucomannans and, at the same time, achieve high yield, ground spruce wood was subjected to a series of sequential two-stage extractions with an Accelerated Solvent Extraction (ASE) apparatus using plain water at 170°C. The total combined extraction time was one hour in all the extractions. The total yield of the dissolved material after 1 h extraction was almost the same, about 25% of the wood, irrespective of the time ratios between the first and the second extractions. The yield of hemicellulose high polymers with the weight average molar mass of 8–10 kDa during the first extraction had a maximum at 20 min extraction time, amounting to about 7% on dry wood basis, and comprising about half of the total extract. Along with the progress of the extraction, the molar mass of the hemicelluloses decreased and hemicellulose-derived low polymers with the weight average molar mass of 6–2 kDa became dominating. The extracted substances were fractionated, mainly according to their molar mass, by sequential precipitation with ethanol, acetone, and methyltert-butyl ether (MTBE). The hemicelluloses with some amount of pectins comprised 83–90% of the precipitated polymeric material and the content of galactoglucomannans was about 80%. [ABSTRACT FROM PUBLISHER]

Miscanthus (Miscanthus sp. Family: Poaceae) was hot-water extracted (two h, at 160 °C) at three scales: laboratory (Parr reactor, 300 cm3), intermediate (M/K digester, 4000 cm3), and pilot (65 ft3-digester, 1.841 × 106 cm3). Hot-water extracted miscanthus, hydrolyzate, and lignin recovered from hydrolyzate were characterized and evaluated for potential uses aiming at complete utilization of miscanthus. Effects of scale-up on digester yield, removal of hemicelluloses, deashing, delignification degree, lignin recovery and purity, and cellulose retention were studied. The scale-dependent results demonstrated that before implementation, hot-water extraction (HWE) should be evaluated on a scale larger than a laboratory scale. The production of energy-enriched fuel pellets from hot-water extracted miscanthus, especially in combination with recovered lignin is recommended, as energy of combustion increased gradually from native to hot-water extracted miscanthus to recovered lignin. The native and pilot-scale hot-water extracted miscanthus samples were also subjected to enzymatic hydrolysis using a cellulase-hemicellulase cocktail, to produce fermentable sugars. Hot-water extracted biomass released higher amount of glucose and xylose verifying benefits of HWE as an effective pretreatment for xylan-rich lignocellulosics. The recovered lignin was used to prepare a formaldehyde-free alternative to phenol-formaldehyde resins and as an antioxidant. Promising results were obtained for these lignin valorization pathways.

Extraction of ground spruce sapwood with pressurized hot water in an accelerated solvent extractor (ASE) at 170°C during 20, 60, and 100 min resulted in isolation of galactoglucomannans and aromatic substances, including lignin. The isolated lignin preparations were characterized by spectrometric (UV, FT-IR,1H NMR, liquid and solid-state13C NMR), chromatographic (RP-HPLC, HP-SEC, GC-FID, and GC-MS), conventional pyrolysis, thermally assisted hydrolysis, and methylation techniques in tandem with GC-MS, and classical wet chemistry (methoxyl groups, total and phenolic hydroxyl groups, derivatization followed by reductive cleavage—DFRC). The content ofβ-O-4 bonds in isolated lignins was similar to that in MWL and their proportion decreased with extraction time. The oxidation of isolated lignins and content of total hydroxyl groups were significantly increased with extraction time. The lignin structure underwent condensation and demethylation reactions during hot-water extraction. The induction of new phenylcoumaran substructures was proposed in isolated lignins. [ABSTRACT FROM AUTHOR]

Ground spruce wood was extracted with pressurized hot water in an accelerated solvent extractor (ASE) at 170°C during 20, 60, and 100 min. Released aromatic substances (from 2.2 to 2.5% on wood basis) were isolated on XAD-7 resin and fractionated into lignin, oligomeric aromatic substances (OAS), and compounds insoluble in methanol (IMC). The separated aromatic fractions, and the ground wood before and after extraction, were characterized by physico-chemical methods (GC, GC-MS, HPLC-SEC, TG, DSC). The major part of the aromatic substances was oligomeric aromatic substances (OAS). This fraction increased significantly with the extraction time, while the yield of dissolved lignin increased only slightly with extraction time. Isolated lignins had a lower molar mass and differed considerably from spruce milled wood lignin (MWL). The isolated lignins were more stable against oxidative thermodegradation than spruce MWL. The UV-extinction coefficients at 280 nm were lower for the isolated lignins than for MWL. [ABSTRACT FROM AUTHOR]

Agricultural residues, such as corn stover, wheat straw, and nut shells show promise as feedstocks for lignocellulosic biorefinery due to their relatively high polysaccharide content and low or no nutritional value for human consumption. Apricot pit shells (APS) were studied in this work to assess their potential for use in a biorefinery. Hot water extraction (HWE; 160 °C, 2 h), proposed to remove easily accessible hemicelluloses, was performed to evaluate the susceptibility of APS to this mild pretreatment process. The chemical composition of APS before and after HWE (EAPS) was analyzed by standard methods and 1H-NMR. A low yield of the remaining HW-extracted APS (~59%) indicated that APS are highly susceptible to this pretreatment method. 1H-NMR analysis of EAPS revealed that ~77% of xylan present in raw APS was removed along with ~24% of lignin. The energy of combustion of APS was measured before and after HWE showing a slight increase due to HWE (1.61% increase). Near infrared radiation spectroscopy (NIRS), proposed as a quick non-invasive method of biomass analysis, was performed. NIRS corroborated results of traditional analysis and 1H-NMR. Determination of antioxidizing activity (AOA) of APS extracts was also undertaken. AOA of organic APS extracts were shown to be more than 20 times higher than that of a synthetic antioxidizing agent. [ABSTRACT FROM AUTHOR]

Lignin recovered from the hot-water extract of sugar maple (Acer saccharum) is used in this study to synthesize adhesive blends to replace phenol-formaldehyde (PF) resin. Untreated lignin is characterized by lignin content and nuclear magnetic resonance (NMR) analysis. The molecular weight distribution of the lignin and the blends are characterized by size exclusion chromatography (SEC). The effect of pH (0.3, 0.65 and 1), ex situ furfural, and curing conditions on the tensile properties of adhesive reinforced glass fibers is determined and compared to the reinforcement level of commercially available PF resin. The adhesive blend prepared at pH = 0.65 with no added furfural exhibits the highest tensile properties and meets 90% of the PF tensile strength. [ABSTRACT FROM AUTHOR]

Temperature-driven models of soil respiration (SR) are crucial for estimating C-balances of arable soils. However, model construction may be severely influenced by tillage operations. The impact of tillage on the temperature dependence of SR was studied to reveal the temporal patterns of model quality of temperature-driven SR-models. To obtain SR, CO 2 fluxes were measured with a dynamic chamber technique in treatments of an energy crop rotation amended with biogas residues (BR) and mineral fertiliser (MF). Measurements were performed with short intervals during the first three days after tillage operations, then with extending intervals between measurements up to 35 days after tillage. Additionally, soil concentrations of hot-water extractable organic carbon (HWC) were determined before and during the experiment. Overall, in all treatments individual CO 2 fluxes were affected by the extent of soil disturbance and fertiliser treatment. The highest tillage-induced fluxes where observed after disking in MF treatment. Tillage also induced an immediate increase of HWC, indicating additional labile C and a fast response of microbial activity. However, the change of HWC lasted only one day and approximated the pre-tillage values within a week. Even though BR soil had a higher HWC content, the increased C mineralisation in one repetition of MF suggests that buried plant residues might have a higher influence on SR after tillage than the type of fertiliser. Directly after soil disturbance by tillage it was impossible to construct temperature-driven models for SR in all treatments. Assuming that the coefficient of determination is appropriate with R 2 ≥ 0.5 and the model quality is good with NRMSE ≤ 0.15, the qualities of the models increased continuously with time, but were unsatisfying for at least two weeks. During this time, SR showed a high sensitivity to changing environmental influences like precipitation and soil moisture or available C for microbial turnover, rather than temperature. The treatment BR showed a less sensitive pattern, which might be attributed to an altered soil structure and microbial activity of soil after long-term application of an organic fertiliser like BR. Therefore, temperature-driven models for the prediction of soil derived CO 2 emissions should be applied carefully for the days and weeks after tillage and verification by measurements in shorter intervals is advisable. [ABSTRACT FROM AUTHOR]

Peatland soils are the most effective and important long-term terrestrial carbon (C) storages. To estimate potential C loss, a valid characterization of soil decomposability, in particular the labile fraction, is of great interest. One of the most labile fractions is hot-water-extractable organic matter (HWOM), often measured as hot-water-extractable carbon (Chwe) and nitrogen (Nhwe). Various studies describe different extraction procedures for mineral soils. Because of methodical differences, it is difficult to compare extracted HWOM amounts directly to each other. For peatland soils, few studies exist. The aim of the present study is the development of a standardized method for the hot-water extraction of peat materials. Therefore, we extracted HWOM in various replicates from different peats on the basis of a standardized extraction method for mineral soils (1 h extraction at 100 °C). We tested how differences in soil/water ratios, extract treatment (filtering vs. not filtering), and sample pretreatment (freeze drying vs. air drying) influence HWOM amounts. The results clearly illustrated the influence of changing soil/water ratios on HWOM amounts. Mean Chweconcentrations ranged between 8 and 34 g kg−1whereas Nhweranged between 0.2 and 2.6 g kg−1. We recommend the extraction under soil/water ratios of 1/800 to provide sufficient volume of solvent for Chwe.If relative differences for Nhweamounts are greater than 15 percent, samples should be extracted again under soil/water ratios greater than 1/300 to avoid analytical errors due to unintended dilution effects. Filtering of centrifuged and decanted extracts before analysis is not necessary. Peat material should be either air dried or freeze dried before extraction. [ABSTRACT FROM AUTHOR]

An in-line pH control system for hot-water extraction of wood was developed and tested for optimal extraction of high-molar-mass hemicelluloses from spruce wood. Automated alkali addition was achieved by combining a controller and HPLC pump with a solid ZrO 2 -based high-temperature and high-pressure pH electrode and a high-temperature and high-pressure Ag/AgCl reference electrode. Three different set points were tested; 600 mV, 575 mV and 550 mV corresponding to a pH at 170 °C of 4.3, 4.6, and 4.85, respectively. An extraction with no pH control was conducted for reference. The extracts were analyzed for total dissolved solids, non-cellulosic carbohydrates, monomeric sugars, average weight molar mass of the hemicelluloses and free acetic acid. The results show that higher extraction pH increases the molar mass but decreases the total yield of dissolved hemicelluloses and also inhibit sugar monomer formation. [ABSTRACT FROM AUTHOR]

Conversion of woody biomass to chemicals, materials and energy requires at least three steps: pretreatment, cracking and conversion. Size reduction is the minimum required pretreatment step prior to further processing. Cracking step is the middle step in woody biomass conversion whereby solid woody biomass is reduced to small building blocks (molecules) or intermediates. The last step in woody biomass conversion is the generation of desired products from the building blocks or intermediates. Reactions involve woody biomass usually as a solid. The (solid–liquid or solid–gas) surface reactions have an apparent zeroth order owing to the complete renewal of surfaces during the dissolution. A vast array of products (chemicals, energy and materials) can be produced from woody biomass based on its four major components: extractives, hemicellulose, lignin and cellulose. Each of these four components has a different degree of resistance to chemical, thermal and biological degradation. The pretreatment step is designed to improve the efficiency of the cracking step. Waste products are commonly produced during pretreatment step for a sugar-based biorefinery due in part to the desire to maximize (or degrade cellulose to) glucose production. Non cellulose components in a sugar-based biorefinery were commonly discarded, starting from the pretreatment step. A synergetic approach is to eliminate the waste generation in pretreatment and inserting a step to turn the otherwise waste into value-added product(s). Hot-water extraction can serve this purpose. With a hot-water extraction process as a pretreatment step, size reduction can be enhanced after the high pressure operation. Value-added products can be produced from the hot-water extraction and the treated woody biomass can be more efficiently transformed in the cracking step: either be sugar-based, or gasification, or pyrolysis, or direct conversion to solid wood products. The synergy stems from the selective separation/removal of components from woody biomass. The reaction of solid component dissolutions from the woody biomass is of zeroth order, following a surface renewal mechanism during the bulk of the hot-water extraction process. [ABSTRACT FROM AUTHOR]

The chemical composition of black liquors obtained from the soda-AQ pulping of birch ( Betula pendula) sawdust was studied as a function of cooking time, effective alkali content, and hot-water pretreatment of the sawdust prior to delignification. Special attention was paid on the formation of lignin-derived materials and low-molecular-mass carbohydrate-derived degradation products containing aliphatic carboxylic acids. In the case of the hot-water-pretreated feedstock, less acetic acid and formic acid and more nonvolatile hydroxy acids (especially monocarboxylic acids) were obtained. The observations can be interpreted as a result of the extensive removal of hemicelluloses during the hot-water pretreatment. [ABSTRACT FROM AUTHOR]

Hot-water extraction (HWE) is a biomass processing method that offers an excellent possibility to generate multiple value-added products. In this study, the pellets were produced from the original spruce sawdust and the sawdust after HWE. Two different arrangements to separate the extracted sawdust from the liquid phase (extract) were applied, namely a rapid solid-liquid separation at high temperature and a slow cooling of extracted sawdust along with the extract. Furthermore, the extracted sawdust was also used several times as an adsorbent to purify the extract from the HWE. The effect of binders (kraft lignin and corn starch) on the pellet properties was also evaluated. Fuel properties, mechanical characteristics and chemical composition of produced pellets were analyzed. The HWE improves the mechanical and energy properties by increasing the pellet's length (2–9% increase), particle and energy density (24% and 31% increase correspondingly) in comparison with the untreated sawdust pellets. Additionally, the pellets from the treated sawdust indicated reduced water absorption capacity and improved strength and durability characteristics compared to the untreated ones. The HWE modifies the lignocellulosic matrix of feedstock resulting in more significant modifications than in the case of binder added to the untreated sawdust. The method of residual sawdust separation from the extract had a pronounced effect on the pellet's characteristics, namely a slow cooling of extracted sawdust in mixture with liquid fraction resulted in a smaller amount of hemicelluloses and monosaccharides in the sawdust and more intensive release (up to 70%) of ash forming elements to the liquid phase. Hot-water extraction presents a beneficial path to valorize woody sawdust by producing several valuable streams, such as hemicelluloses, fuel pellet and biochemicals. [Display omitted] • Hot-water extraction (HWE) generates a range of high-value streams from biomass. • HWE improves the mechanical properties and energy content of pellets. • Slow cooling of extracted sawdust with liquid significantly decreased ash content. • The effect of binder addition is more pronounced for untreated sawdust pellets. • Combustion and pyrolysis reactivities of the pellets were slightly affected by HWE. [ABSTRACT FROM AUTHOR]

Integration of biomass pretreatment with pyrolysis offers an opportunity to improve end-product quality and conversion efficiency. In this study, sugar maple ( Acer saccharum ) was subjected to both hot-water extraction (HWE) at 160 °C (at residence times of 0.5 h, 1.0 h, and 2.0 h) and electron beam (EB) irradiation at a dose of 1000 kGy. Pyrolysis studies were then conducted on all the treated samples at 550 °C using a bench scale pyroprobe-gas chromatography–mass spectrometry (Py-GC/MS). The HWE samples were selected for further evaluation in catalytic pyrolysis using HZSM-5 catalysts for the production of aromatic hydrocarbons. Analysis of the hot-water treated sample at 160 °C for 2 h showed that HWE increased the volatile mater and decreased the fixed carbon and ash contents; also the glucan content increased by 24% and the xylan decreased by 54%. Derivative thermogravimetry (DTG) analysis indicated that EB irradiation reduced the crystallinity of the sugar based polymers while HWE solubilized the hemicellulose fraction. The pyrolysis results showed that EB irradiation increased the formation of furanic aldehydes (furfural and 5-hydroxymethylfurfural (5-HMF)) and decreased hydroxyacetaldehyde (HAA) and levoglucosan (LG). By contrast, HWE increased the yield of LG, HAA, 5-HMF and furfural; but, decreased the yields of acetic acid (HAc), hydroxyacetone, and other ketones. For the HWE-2 h sample, LG formation increased from 4.45 wt.% to 11.57 wt.% and HAc decreased from 4.87 wt.% to 2.40 wt.%. Catalytic pyrolysis of HWE samples with HZSM-5 zeolite showed that the carbon yields of monoaromatic hydrocarbons increased. HWE treatment at 160 °C for 2 h increased the yield of benzene by 46%, toluene by 35% and xylene by 26%. Pyrolysis-TGA also indicated that HWE decreased the formation of char/coke. Overall, the reduction in the formation of acids and ketones caused by HWE suggest that it could be used to improve bio-oil quality in non-catalytic pyrolysis whilst the increase in the yield of monoaromatic hydrocarbons indicate that HWE could be used to enhance the carbon efficiency in catalytic pyrolysis. [ABSTRACT FROM AUTHOR]

A high-temperature pH measuring system was developed, calibrated, and validated for measuring pH during hot-water extraction of hemicelluloses from wood. The aim was to measure in-line pH during extraction in order to control the extraction pH. An yttria-stabilized Zr/ZrO 2 electrode was used for measuring the potential. Phthalate and phosphate buffers were used to calibrate the system at 160, 170, and 180 °C. Also, different buffer concentrations were tested for stability. Tap water and different salt solutions were tested to investigate the system response to pure water and water solutions. Calibration curves were acquired from the calibration results and Nernst equation was used to calculate the in-line pH during wood extractions. The setup showed stable and reliable potential readings during both calibration tests and wood extractions. The in-line pH was found to be 0.35 pH units higher than when measured at room temperature with a conventional pH meter. [ABSTRACT FROM AUTHOR]

Highlights: [•] Xylans were extracted from sugarcane bagasse with hot-water and alkaline peroxide. [•] Xylose units in the main chain of xylans are substituted by arabinose at C2 and C3. [•] The arabinoxylans extracted with water at high temperature contained less arabinose. [•] The water-soluble arabinoxylans are more branched, acetylated and low-molar-mass. [•] Water-extracted hemicelluloses contain more lignin than alkaline peroxide extracted. [ABSTRACT FROM AUTHOR]

Highlights: [•] Different wood particle sizes were studied for hemicellulose extraction at 170°C. [•] Smaller particle sizes gives faster extraction and slightly better yield. [•] The reaction order was 1.5st for 0.5–2mm and pseudo-first for 2–12.5mm particles. [•] Hemicellulose molar-mass dropped rapidly during the first 10min of extraction. [•] For maximum yield of high-molar-mass hemicelluloses 20min extraction was optimal. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to further evaluate the viability of the integrated pulp mill biorefinery concept. On one side the properties of hot-water pre-extractions were studied, in order to determine the effect of extraction on soda pulping and bleachability. On the other side, the performance of two dry-strength agents on the paper properties obtained from extracted and un-extracted (control) samples were investigated. It was found that hemicelluloses removal of the depithed bagasse chips was 24.6% at 140°C for 10min with a solid to liquor ratio (S:L) of 1:8 (w/w), and that mass removal increased with extraction time and temperature. The hemicelluloses removal reached 65.5% at 170°C for 30min. The residual extracted bagasse were subjected to soda pulping at 160°C for 1h with 11, 14 and 17% active alkali charge and a S:L of 1:5 (w/w). Conventional elemental chlorine free bleaching (D 0 ED 1) sequence was also used to compare the results with the un-extracted ones. Compared with the control sample, the overall pulp yield for extracted bagasse increased considerably while Kappa number and rejects decreased moderately. In addition, yield and Kappa number of the pulps improved with increasing alkali charge from 11% to 17%. After pre-extraction, better brightness compared with the control pulp was also shown. However, hot-water extraction was found to negatively impact some pulp properties including decreases in burst and tensile indices while addition of chitosan and cationic starch could improve the strength properties. Overall, papers treated with chitosan gave superior mechanical properties compared to the papers treated with cationic starch. [Copyright &y& Elsevier]

Abstract: Two methods for separation of polymeric galactoglucomannans (GGMs) from a hot-water extract of spruce wood, i.e., membrane filtration and precipitation in ethanol–water, were compared. Filtration through a series of membranes with different pore sizes separated GGMs of different molar masses, from polymers to oligomers. Only polysaccharides were precipitated in ethanol–water. With the optimal water content of 5–15%, the precipitated amount was about 6% on wood basis. The average molar mass of the precipitated polysaccharides was 10–12kDa with a molar mass range of 4–20kDa. GGMs comprised about 80% of the precipitated hemicelluloses. Other precipitated polysaccharides were mainly arabinoglucuronoxylans and pectins (rhamnogalacturonans). Analysis of a lignin-free, ethanol-precipitated GGM preparation by 13C NMR spectroscopy verified that it was structurally almost identical with a GGM-rich ethanol precipitate obtained from spruce wood by extraction at much milder conditions, 90°C for 60min. [Copyright &y& Elsevier]

Abstract: Interactions of organic pollutants with soil organic matter can be studied by adsorption of the pollutants on well-characterized soil samples with constant mineralogy but different organic matter compositions. Therefore, the objectives of the current study are establishing a set of different, well-characterized soil samples by systematic modifications of their organic matter content and molecular composition and prove these modifications by advanced complementary analytical techniques. Modifications were done by off-line pyrolysis and removal/addition of hot-water extracted organic fraction (HWE) from/to the original soil sample. Both pyrolysis-field ionization mass spectrometry (Py-FIMS) and synchrotron-based C- and N- X-ray absorption near-edge structure spectroscopy (XANES) were applied to investigate the composition of the soil organic matter. These complementary analytical methods in addition to elemental analysis agreed in showing the following order of organic matter contents: pyrolyzed soil

Abstract: Woody biomass is renewable only if sustainable production is imposed. An optimum and sustainable biomass stand production rate is found to be one with the incremental growth rate at harvest equal to the average overall growth rate. Utilization of woody biomass leads to a sustainable economy. Woody biomass is comprised of at least four components: extractives, hemicellulose, lignin and cellulose. While extractives and hemicellulose are least resistant to chemical and thermal degradation, cellulose is most resistant to chemical, thermal, and biological attack. The difference or heterogeneity in reactivity leads to the recalcitrance of woody biomass at conversion. A selection of processes is presented together as a biorefinery based on incremental sequential deconstruction, fractionation/conversion of woody biomass to achieve efficient separation of major components. A preference is given to a biorefinery absent of pretreatment and detoxification process that produce waste byproducts. While numerous biorefinery approaches are known, a focused review on the integrated studies of water-based biorefinery processes is presented. Hot-water extraction is the first process step to extract value from woody biomass while improving the quality of the remaining solid material. This first step removes extractives and hemicellulose fractions from woody biomass. While extractives and hemicellulose are largely removed in the extraction liquor, cellulose and lignin largely remain in the residual woody structure. Xylo-oligomers, aromatics and acetic acid in the hardwood extract are the major components having the greatest potential value for development. Higher temperature and longer residence time lead to higher mass removal. While high temperature (>200°C) can lead to nearly total dissolution, the amount of sugars present in the extraction liquor decreases rapidly with temperature. Dilute acid hydrolysis of concentrated wood extracts renders the wood extract with monomeric sugars. At higher acid concentration and higher temperature the hydrolysis produced more xylose monomers in a comparatively shorter period of reaction time. Xylose is the most abundant monomeric sugar in the hydrolysate. The other comparatively small amounts of monomeric sugars include arabinose, glucose, rhamnose, mannose and galactose. Acetic acid, formic acid, furfural, HMF and other byproducts are inevitably generated during the acid hydrolysis process. Short reaction time is preferred for the hydrolysis of hot-water wood extracts. Acid hydrolysis presents a perfect opportunity for the removal or separation of aromatic materials from the wood extract/hydrolysate. The hot-water wood extract hydrolysate, after solid-removal, can be purified by Nano-membrane filtration to yield a fermentable sugar stream. Fermentation products such as ethanol can be produced from the sugar stream without a detoxification step. [Copyright &y& Elsevier]

Hot-water extraction (HWE) of hardwoods may be performed as a part of sequential disintegration of hardwoods in a biorefinery system. In this study, different sulfur-free delignification methods were investigated for their respective effectiveness in lignin removal from unextracted (SM) and hot-water-extracted sugar maple (SMHWE). Peracetic acid and tetrahydrofurfural alcohol were investigated as attractive delignification agents, which may be produced on site (biorefinery products). Oxygen was used in combination with the organic solvents acetone and ethanol, designed sugar fermentation products from hydrolyzed hot-water extracts. The delignification degree and delignification selectivity were compared for SM and SMHWE. SMHWE consistently showed a higher degree of delignification. Also, a higher selectivity was observed in delignification of SMHWE with all investigated agents except peracetic acid. Oxygen delignification in an acetone:water mixture was the most selective in delignification of SMHWE. The delignification results obtained using the acetone-water-oxygen system for sugar maple were confirmed using Eucalyptus (unextracted, Eu, and hot-water-extracted, EuHWE). These results indicate that the structural and chemical changes occurring during HWE of hardwoods provide for a more efficient subsequent delignification with a wide range of delignification agents. [ABSTRACT FROM AUTHOR]

Abstract: Ground spruce wood was extracted with water at 170°C at four different pH levels (3.8, 4.0, 4.2 and 4.4) achieved by using phthalate buffers. Static batch extractions were carried out in an accelerated solvent extractor (ASE-300). The extracted non-cellulosic carbohydrates, predominantly galactoglucomannans (GGMs), were characterised mainly by sugar unit analysis and molar mass determination. Compared to extraction with plain water, extractions with phthalate buffer solutions gave similar yields of non-cellulosic carbohydrates, but gave up to 70% less monosaccharides, and consequently higher molar masses of extracted GGMs. Moreover, at these pH levels, the hydrolysis of acetyl groups were decreased by 40% compared to extraction with plain water, thus maintaining the water solubility of GGMs. It is concluded that hot water extraction of hemicelluloses in high-molar-mass form (average Mw about 10kDa) from wood in good yields (8% of wood) demands appropriate control of pH, to a level of about 4. [Copyright &y& Elsevier]

Abstract: A combination of a twin-screw extrusion and an acid-catalyzed hot water extraction process performed at a bench-scale was used to prepare high monomeric xylose hydrolysate for cellulosic production. The influences of the screw speed (30–150rpm), barrel temperature (80–160°C) and corresponding specific mechanical energy of the extruder on the structural properties of the pretreated rice straw, sugar concentration and conversion were investigated. The optimal condition for the extrusion step was determined to be 40rpm with 3% H2SO4 at 120°C; the optimal condition for the extraction step was determined to be 130°C for 20min. After the pretreatment at the optimal condition, 83.7% of the xylan was converted to monomeric xylose, and the concentration reached levels of 53.7g/L. Finally, after the subsequent enzymatic hydrolysis, an 80% yield of the total saccharification was obtained. [Copyright &y& Elsevier]