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The object of research is the black liquor of the alkaline pulping sample Paulownia Clone in Vitro 112® with active alkali consumption of 14, 18 and 22 % in Na2O units from the mass of completely dry raw materials. The problem solved in the work is related to the formation of waste in the form of black liquor during pulp production. It is noted that as a result of the production of 1 ton of cellulose, up to 7 tons of black liquor is formed. In the course of the work, an analysis of the total titrated and active alkalinity in the white and black liquor after cooking paulownia wood was carried out, and the pH value was determined. The dependence of the content of dry substances in black liquor on the consumption of active alkali, the duration of cooking, the presence of a catalyst, and the final temperature of the delignification process is given. The amount of organic and mineral components of dry substances of black liquor per 1 ton of air-dry fibrous semi-finished products was calculated. It was established that with an increase in temperature by 20 °C (from 150 to 170 °C) and a duration of approximately 1.5 times (from 60 to 90 min and from 90 to 150 min), with the same consumption of active alkali and the use of a catalyst in the conditions after sodium pulping, the content of dry substances in the black liquor increases by 1.5–3 %. This regularity is explained by the transition into the solution of a greater number of dissolution products of lignin, hemicelluloses, and mineral substances. Estimated values for the content of mineral and organic substances in black liquor after cooking paulownia wood for a duration of 150 min and a final temperature of 170 °C at different consumptions of active alkali and the use of catalysts in the form of anthraquinone and ethyl alcohol are within the range of 1024–1518 kg per 1 ton dry pulps of normal yield and can be used in practice. The obtained results can be used to form an assessment of the black liquor as an additional resource potential for the economy of production. [ABSTRACT FROM AUTHOR]

Bio-derived materials are becoming increasingly sought-after as a sustainable alternative to petrochemical-derived polymers. In the present pilot-scale study, a hemicellulose-rich compression screw pressate, obtained from the pre-heating stage of thermo-mechanical pulping (TMP) of radiata pine, was purified by treatment with adsorbent resin (XAD7), then ultrafiltered and diafiltered at 10 kDa to isolate the high-molecular weight (MW) hemicellulose fraction (yield 18.4% on pressate solids), and, finally, reacted with butyl glycidyl ether to plasticise the hemicelluloses. The resulting light brown hemicellulose ethers (yield 102% on the isolated hemicelluloses) contained ca. 0.5 butoxy-hydroxypropyl side chains per pyranose unit and had weight- and number-average MWs of 13,000 Da and 7200 Da, respectively. The hemicellulose ethers may serve as raw material for bio-based products such as barrier films. [ABSTRACT FROM AUTHOR]

A novel thermo-mechanical pulping (TMP) process has been developed to produce a by-product rich in high-molecular weight (MW) hemicelluloses, a potential raw material for barrier coatings and films. This process uses prehydrolysis to solubilise the hemicelluloses followed by chip compression to separate the soluble material from the wood matrix. The pressate from the chip compression stage was dark-coloured and had a high content of high-MW hemicelluloses and lignin. However, isolating the high-MW material from the pressate directly by ultrafiltration was not feasible because of membrane fouling by dissolved lignin and wood extractives, while coloured impurities are undesirable for many potential applications. To solve these problems the pressate was purified using XAD adsorbent resin to remove low-MW lignin, extractives and colour. Ultrafiltration of the purified pressate yielded lightly coloured high-MW hemicellulose with a low content of lignin and well suited for barrier films and coatings. [ABSTRACT FROM AUTHOR]

The cellulose nanocrystals (CNCs) were produced from spruce wood using less hazardous and toxic reagents with understanding of influence of process parameters on CNCs properties. This study employed acetosolv pulping followed by alkaline-peroxide bleaching, eliminating highly reactive chemicals such as Na-chlorites and Na-sulfite for cellulose pulp extraction from spruce wood. Cellulose pulp yield of 41.5 ± 0.7 wt% of dry wood was obtained from pulping followed by bleaching treatment. Cellulose pulp was hydrolyzed with 59.0–65.0 wt% sulfuric acid followed by ultrasonic treatment to produce CNCs. CNCs yield of 8.0 ± 3.2 wt% of dry wood was obtained at 65 wt% acid concentration and yield of 25.1 ± 0.7 wt% at 62 wt% acid concentration. The optimization of acid hydrolysis and ultrasonic treatment resulted in CNCs with high aspect ratios (length/width) up to 48.1. It was demonstrated that higher acid concentration requires lower intensity of ultrasonic treatment for CNCs dispersion, and that higher intensity could enhance aspect ratio without impacting the crystallinity index. However, ultrasonic treatment for longer than 5 min led to destruction of the whisker morphology of CNCs. The extracted CNCs possess high crystallinity index of 80.8 ± 1.7 %, low residual hemicellulose (<2.0 %) and lignin (<0.7 %), and high-char content of 26.7 wt% from thermal degradation. [Display omitted] • S and Cl free pulping and bleaching processes were used for cellulose extraction. • Pure cellulose nanocrystals from spruce were obtained in high yield. • High aspect ratio of up to 48 and crystallinity index of 80.8 ± 1.7 % were achieved. • Ultrasonic treatment showed no negative impact on the crystallinity index of CNCs. [ABSTRACT FROM AUTHOR]

A new laboratory reactor to perform in situ studies of structural changes in wood during soda pulping using synchrotron X-ray tomography is presented. The reactor is of recirculation type to provide stable reaction conditions and mimic the industrial situation. Experiments have been performed using this reactor in situ at a synchrotron microtomography beamline to provide sequences of 3D images from which measurement of wood cell wall thickness have been possible for the first time. The results showed that the cell wall thickness increased significantly in the early stage of pulping (<10 min), which is due to the transportation of cooking chemicals through the tracheids, resin channels and pits into the cell wall, which is swollen with the increased pH. Subsequently, the cell wall thickness reduces over the processing time up to 60 min with a high rate, which is inferred to be due to the dissolution and transport of lignin and hemicellulose from the secondary walls, allowing for better transportation of active chemicals deep through the cell wall layers. After 60 min processing, the cell wall thickness reduction rate reduced, as dissolution of lignin and hemicelluloses from the cell walls ceased, while the remaining dissolution occurs mainly at the middle lamella. [ABSTRACT FROM AUTHOR]

Cannabis indica stems were hydrolyzed with subcritical water at various temperatures, reaction times, and feed concentrations. The highest total yield of reducing sugars of 16.4 wt % was obtained at 190 °C in 37.5 min with a feed concentration of 3.5 wt %. Solid residues from the optimized process were treated with 0.5 M NaOH (pulping) and 0.5–3 % H2O2 (bleaching) to isolate cellulose fibers. The maximum yield of cellulose was 34.8 wt % with lowest lignin content of 0.5 wt %. With the removal of hemicellulose and lignin through the integrated hydrothermal processes, the crystallinity index and thermal stability of the cellulose fibers increased. [ABSTRACT FROM AUTHOR]

Herein, cellulose nanocrystals were synthesized from oil palm fronds (CNC-OPF) involving two pretreatment approaches, viz. autohydrolysis and soda pulping. The pretreatments were applied individually to OPF fibers to assess their influence on CNCs' physicochemical and thermal properties. CNC-OPF samples were assessed using complementary characterization techniques, which confirmed their purity and characteristics. CP/MAS 13C NMR and TEM studies revealed that autohydrolysis pretreatment yielded CNCs with effective hemicellulose and extractives removal compared to that of soda pulping. XRD analysis demonstrated that autohydrolysis-treated CNC-OPF contained a much higher crystallinity index compared to soda pulping treatment. BET measurement disclosed a relatively higher surface area and wider pore diameter of autohydrolysis-treated CNC-OPF. Autohydrolysis-treated CNCs were applied as a reinforcement filler in alginate-based hydrogel beads for the removal of 4-chlorophenol from water, which attained a q max of 19.168 mg g−1. BET analysis revealed the less porous nature of CNC-ALG hydrogel beads which could have contributed to hydrogel beads' relatively lower adsorption capacity. The point of zero charge of CNC-ALG hydrogel beads was 4.82, suggesting their applicability only within a short solution pH range. This study directs future studies to unveil the possibilities of functionalizing CNCs in order to enhance the adsorption performance of CNC-immobilized hydrogel beads towards 4-chlorophenol and other organic contaminants. [Display omitted] • Autohydrolysis and soda pulping pretreatments were assessed to characterize CNC-OPF. • Autohydrolysis yielded CNC-OPF with enhanced physicochemical and thermal properties. • Autohydrolysis-treated CNC-OPF were reinforced to prepare alginate-based beads. • OPF-derived CNC-alginate hydrogel beads revealed potential 4-CP adsorption capability. [ABSTRACT FROM AUTHOR]

Conventional pulping processes, such as soda, soda‐Antraquinone (AQ), and kraft, are currently used for non‐wood pulping. The main challenges of non‐wood pulping in conventional pulping processes are (1) large amounts of silica cause silica‐related operational difficulties in the process; (2) large amounts of fines/parenchyma cells decrease the drainage; and (3) the bulky nature of raw materials increases the collection/transportation cost, hampering large‐scale commercial operations. Alternative pulping processes are therefore being developed. This paper reviews the current status of alternative non‐wood pulping processes and their integration with the biorefinery concept. Several promising methods have been investigated at the laboratory or pilot scale. Organic acid and potassium hydroxide pulping processes are attractive alternatives for non‐wood pulping. Dissolved lignin and hemicelluloses in spent liquor can lead to the production of valuable co‐products, fitting well with the integrated biorefinery concept. Non‐wood biomass can be important raw material for pulping in forest‐deficient countries. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

In this study, aimed at valorization of industrial xylan-rich hemicelluloses (a by-product of dissolving pulp process), water-soluble hemicelluloses were fabricated with mild acetylation in 1-ethyl-3-methylimidazolium acetate ionic liquid (EmimAc) and dichloroacetyl chloride (Cl 2 AcCl) system by a facile and novel method. The structure of the acetylated hemicelluloses was characterized by FT-IR and NMR spectra. The resultant modified products could fully dissolve in water with the degree of substitution (DS) valued between 0.17 and 0.37. Structural characterization indicated that the modified hemicelluloses were chiefly composed of the (1 → 4)-linked β-D-Xylp backbone with hydroxyl or -COCH 3 linked to O-2 and O-3 of the Xylp units. Moreover, the mild acetylation was achieved by one-pot method, in which the hemicelluloses reacted with mixed anhydride produced between EmimAc and Cl 2 AcCl rather than Cl 2 AcCl. Rheological behavior measurements revealed that acetylated hemicelluloses solutions showed shear-thinning behavior and indicated lower viscosity compared with those of the referenced hemicelluloses. The excellent water-solubility of industrial hemicelluloses would widen its application field and be easier for its conversion into desired chemicals. • Water-soluble hemicelluloses were innovatively prepared by in-situ acetylation. • Acetylated hemicelluloses with low DS between 0.17 and 0.37 were obtained. • The resultant water-soluble hemicelluloses exhibited shear-thinning behavior. [ABSTRACT FROM AUTHOR]

The kraft process remains the dominant chemical pulping process but still struggles with extensive hemicellulose degradation. Such degradation has previously been mitigated through the use of anthraquinone; but due to it recently being found to have carcinogenic properties, anthraquinone is now being phased out. One alternative, sodium dithionite, was initially investigated in the 1950s but was found to be unviable. The present study investigated whether sodium dithionite could be made viable through the use of different processing parameters, using mannose as a model compound and measuring the yield of mannitol in the various systems using gas chromatography with flame ionization detection (GC-FID) and nuclear magnetic resonance (NMR). Alkalinity was found to be crucial; at pH 14 as well as pH 7, dithionite indeed proved unviable, but if pH was kept at either 8 or 10 significant reduction was seen to occur. The best results were obtained at pH 10 when a lower temperature (70°C) was used to compensate for alkaline degradation of the mannose reactant. [ABSTRACT FROM AUTHOR]

Two previous treatments have been applied to the ethanol-soda paste process on Eucalyptus globulus wood to evaluate its influence on the properties of the obtained cellulose pulps. The treatments consisted of a first optimized stage of autohydrolysis (temperature: 180 °C, time: 30 min) to obtain the maximum extraction rate of hemicellulosic derivatives preserving the glucan, followed by enzymatic oxidative delignification by a laccase/mediator system (syringaldehyde). Experimental designs have been applied for the optimization of processes. The optimum operating conditions in the enzymatic delignification stage were: Lacasse concentration 18,5 U/g, concentration of syringaldehyde 1,5 %, temperature 45 °C and operating time 60 min., with which an elimination of the 16,8% of the existing lignin in the raw material and slightly affects the glucan (it is conserved between 82,2 % and 89,7 % of the initial glucan). Two liquid, recoverable phases are obtained, rich in hemicellulose and polyphenolic derivatives. In this process scheme to obtain ethanol-soda cellulosic pulp from eucalyptus wood requires a lower concentration of chemical reagents, shorter operating times and lower temperatures, which is an economic and environmental improvement over the conventional pulping process. [ABSTRACT FROM AUTHOR]

In this work, the thermal decomposition of exhausted sugar beet pulp (ESBP) at a heating rate of 10 °C min−1 and the resulting evolved gases were examined by thermogravimetric (TG) analysis coupled with Fourier transform infrared (FTIR) spectroscopy. The results obtained in the identification of biomass fiber components were compared with those of the Van Soest method. The TG curves obtained in the fast thermal pyrolysis of ESBP exhibited substantial mass loss peaks primarily associated with the decomposition of pectin, hemicellulose and cellulose at 233, 269 and 341 °C, respectively. Lignin, however, was more difficult to decompose since its mass loss occurred over a broad temperature range (200–800 °C). The FTIR spectra obtained at these temperatures were consistent with the formation of large amounts of gases such as CO2, CO, H2O and CH4 in addition to a mixture of organic products including aldehydes, ketones, organic acids, alkanes and phenols. Based on these results, the proposed approach allows lignocellulosic components in exhausted sugar beet pulp biomass to be efficiently screened. Also, the new approach is faster, operationally simpler and more economical than the Van Soest method. [ABSTRACT FROM AUTHOR]

Population balance model successfully described the flocculation process induced by cationic polyacrylamide (CPAM) and provided an excellent agreement between the experimental and predicted floc size. • Population balance model predicted very well the experimental flocculation process. • High charge CPAM resulted in lower collision efficiency and lower restructure rate. • High charge CPAM resulted in stronger flocs. • Shear rate had negative effect on collision efficiency. In order to predict and control the CPAM induced flocculation process for lignin recovery and subsequent dissolved hemicelluloses utilization from pre-hydrolysis liquor (PHL), quantitative population balance model which can describe aggregation, breakage and restructure phenomenon in the flocculation process was developed to describe the process. The simulation results showed, in general, high charge CPAM resulted in lower collision efficiency, lower restructure rate and stronger flocs than the lower charged CPAM. The increase of CPAM dosage had positive effect on collision efficiency and restructure rate and negative effect on energy dissipation rate. With the increase of temperature, low charge density CPAM flocculation system experienced more significant change regarding energy dissipation rate and restructure rate. The collision efficiency was not significantly affected by the temperature change for both CPAMs. Shear rate had negative effect on collision efficiency, positive effect on energy dissipation rate and restructure rate. The addition of salt slightly increased the collision efficiency, decreased the energy dissipation rate for both CPAMs system. More negative effect is observed for high charge density flocculation system. [ABSTRACT FROM AUTHOR]

• Chitosan treatment slowed down pulp breakdown development in harvested longan fruit. • Chitosan reduced cell wall-degrading enzymes activities in harvested longan fruit. • Chitosan helped preserve cell wall polysaccharides in pulp of harvested longan fruit. • Chitosan suppressed cell wall disassembly in pulp of harvested longan fruit. • Chitosan is a novel approach for keeping the quality of harvested longan fruit. Longan pulp is an excellent source of polysaccharides and other nutrients that have many health benefits. However, longans is susceptible to pulp breakdown after harvest and loses its nutrition values. To solve this problem, this study aimed to study the effects of a novel chitosan, Kadozan, on pulp breakdown index, contents of pectin, cellulose and hemicelluloses, and activities of enzymes in longan pulp relating to disassembly of polysaccharides (XET, PE, PG, β -Gal, and cellulase). The data illustrated that, compared to the control longans, chitosan-treated longans contained higher amounts of CWM, CSP, ISP, cellulose and hemicelluloses, but exhibited lower pulp breakdown index, lower activities of cell wall-disassembling enzymes, and contained lower WSP amount. These results suggested that Kadozan with a dilution of 1:500 (V Kadozan : V Kadozan + Water) could significantly decrease activities of disassembling-enzymes and depolymerization of polysaccharides in cell wall, and subsequently alleviate pulp breakdown and prolong storage-life of postharvest longans. [ABSTRACT FROM AUTHOR]

Cellulose and hemicellulose are usually considered the sources of formic and acetic acids that are obtained during ethanol pulping process, while our research reveals that lignin is another critical source of acids in the process. In this research, the sample lignin was purified and treated under ethanol pulping conditions and the factors that influence the yields of acids including: ethanol ratio (0–100%), residence time (30–210 min), reaction temperature (150–200 °C) and the effect of residual oxygen in the vessel, were tested separately. The yields of acids were identified using UPLC, the volatile products were characterized by GC–MS and the residual lignin was characterized by 13C NMR. The results indicated that the residual oxygen in the reaction vessel acted as an oxidant and the maximum yields of formic and acetic acid are 5.5% and 4.8% (g/g-lignin) from reed and aspen lignin, respectively. For understanding mechanism of the reaction, six lignin model compounds (LMCs) were treated and analyzed in the same reaction conditions; the subsequent results showed that both formic and acetic acid could be detected for all the LMCs tested. On the bases of the experimental results, the reaction pathways have been proposed and discussed. • Formic and acetic acids are generated from lignin in the ethanol pulping process. • The yields of acids and influential factors were evaluated. • Proposed reaction pathways. [ABSTRACT FROM AUTHOR]

Bamboo-willow is a type of fast-growing wood with a high hemicellulose content. In the present study, the effects of phosphoric acid addition on the main components of bamboo-willow and pre-hydrolysis liquor (PHL) were explored, and subsequently the pre-hydrolyzed bamboo-willow chips were cooked, O-H-P bleached, and acid post-treated to produce dissolving pulp. The results showed that adding phosphoric acid to the pre-hydrolysis stage effectively removed hemicellulose and increased the cellulose content of the pre-hydrolyzed bamboo-willow. The major component of the hemicelluloses was xylan/xylose, which represented approximately 62% to 78% of the total sugars in the PHL. Glucose was the most abundant sugar that was produced, apart from xylose, and represented approximately 12% to 25% of the total sugars in the PHL. Additionally, 73% to 83% of the total sugars in the PHL were in an oligomeric form. The obtained bamboo-willow dissolving pulp could be used to produce viscose rayon with a 92.1% α-cellulose content, 4.77% hemicellulose content, and 675 degree of polymerization. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is one of the most abundant raw materials in the world, and it is mainly composed of carbohydrate polymers (cellulose and hemicellulose) and lignin. Its applications vary from the production of pulp and paper, to the most recent plant-based bioethanol production, which has challenge due to low hydrolysis conversion rates by the inherit recalcitrance of biomass. The biomass is naturally resistant due the high complexity in the component organization and interaction in the cell wall. The application of pretreatment technologies is one of the most used strategies to overcome biomass recalcitrance. These techniques often require a catalyst to modify the lignocellulosic structure which can be acids, alkaline compounds, ionic solutions, organic solvents, and even pressurized steam among others. The type of catalyst dictates the name of the pretreatment involved. This work presents an overview of these strategies, along with some recent contributions from the scientific community to improve biomass conversion technologies. The discussion is focused on the key factors related to the recalcitrance and conversion process, as well as the composition and physicochemical properties. [ABSTRACT FROM AUTHOR]

Conversion of a hemicellulose‐rich pre‐pulping extract into long‐chain alcohols could alleviate problems facing the liquid fuel supply and could boost the revenues of pulp mills. Kraft pulping requires only the cellulose fraction of wood, leaving much of the hemicellulose available for extraction and subsequent conversion into gasoline‐blendable alcohols. Three possible pathways for upgrading the hemicelluloses are: CKA: carboxylates → ketones → alcohols; CEA: carboxylates → esters → alcohols, and CHEA: carboxylates → acids → esters → alcohols. The scenarios were modeled using AspenPlus® to determine material and energy balances. Economic parameters were determined using the Aspen Process Economic Analyzer. The minimum ethanol selling price (MESP) for a 1000 tpd facility, which takes into account the operating and capital costs, was found to be: $3.31 for CKA, $4.56 for CEA, and $4.26 for the CHEA. The cost of hydrogen necessary for hydrogenolysis proved to be a notable expense. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

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

The spent pulping liquor (SPL) obtained from straw processed by soda (alkaline) pulping contains dissolved non-sulfonated lignin. The lignin can be separated from SPL using acid or cationic flocculants which are potentially hazardous to the environment. In this study, the performance of the biobased protein flocculant hemoglobin (HEM) with and without added calcium chloride was compared with that of a high charge density synthetic cationic flocculant, poly (diallyldimethylammonium chlorides) (pDADMAC). Turbidity measurements gave overly broad concentration ranges for optimal lignin removal which may be related to the mechanism of flocculation which requires several major steps: Conversion of dissolved lignin to particulate lignin, formation of particulate lignin flocs, and subsequent sedimentation of these flocs. An optimal flocculant concentration or concentration range was estimated using the three methods: average Zeta potential corresponding to the lowest turbidity range; a novel method using the maximum percent pellet mass calculated using the dried masses of the pellet and supernatant after centrifugation; measurement of supernatant lignin using spectroscopy. HEM light absorption interfered with spectroscopic lignin determination, and a method for correcting the measurements was devised. This study shows that HEM is an effective flocculant for nonsulfonated lignin in SPL. The HEM-lignin complex is a potential high protein component of animal feed. [ABSTRACT FROM AUTHOR]

In the course of the Ioncell-P process, hemicelluloses are extracted from wood pulps by a mild treatment with an ionic liquid (IL) water mixture, and the result is a high-purity dissolving pulp. The aim of the present work is to study the influence of pulp origin concerning different wood species and pulping processes on the resulting pulp purity and yield after extraction with IL/water, while the IL is 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). The raw materials were chosen from commercial alkaline kraft and acid sulfite paper and dissolving pulps prepared from both hardwood (HW) and softwood (SW). The extraction was followed by a filtration step to separate the cellulose and the hemicellulose fractions. The hemicelluloses were precipitated from the IL/water filtrate. In general, the Ioncell-P process proved to be more selective toward the removal of xylan as compared to glucomannan indicating that HW pulps are easier to purify than those of SW. It was possible to reach high alpha pulp qualities by the extraction process. [ABSTRACT FROM AUTHOR]

Full components utilization of corn stalk was investigated by the combine processes of prehydrolysis and alkaline sulfite cooking. Prehydrolysis was employed to remove hemicelluloses prior to cooking. Glucose yield of 76.8 g/kg and xylose yield of 118.4 g/kg corn stalks were obtained from the hydrolysis of hemicelluloses at 150 °C for 3 h. Significantly, cellulose was largely preserved during prehydrolysis as indicated by the pulp yield from 54 % to 62 % from the alkaline sulfite cooking. Paper sheet showed superior physical strength over hardwood pulp, e.g. tensile index 97.4 N·m/g, tear index 6.6 mN·m2/g and burst index 5.2 kPa·m2/g. In addition, lignin in spent liquor of alkaline sulfite cooking was recovered as lignosulfonate surfactant which reduced the surface tension of water to 38.2 mN/m at a concentration of 15 g/L. The combined processes of prehydrolysis and alkaline sulfite cooking enables full utilization of cellulose, hemicelluloses, and lignin, and therefore has great potential to industrial application. [Display omitted] • Hemicelluloses in corn stalk were extracted by prehydrolysis prior to alkaline sulfite pulping. • Highest sugar yield of 287.7 g/kg corn stalk was obtained from prehydrolysis. • Corn stalk pulp from alkaline sulfite cooking showed superior strength over hardwood pulp. • Lignosulfonate was formed during pulping and showed excellent surfactivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Greener alternative towards conventional alkali pulping. • Harnessing the potential of paddy straw and pine needle in combination for pulping. • Lignin removal by novel combinatorial approach of chemical and microbial treatment. Paddy straw (PS) and pine needles (PN) are one of the challenging biomasses in terms of disposal and compost making due to their high silica and tannin contents. Particulate air pollution, loss of biodiversity and respiratory impairments are some of disastrous outcomes caused by burning. However, high percentage of cellulose and hemicellulose makes them potential substrate for paper and pulp industries. The main aim of work was to study and utilize a combinatorial approach of weak chemical treatment and lignin degrading fungal species as agents of effective production of lignin modifying enzymes (LME's) for lignin depolymerisation from the biomasses. Phanerochaete chrysosporium was found to be the best degrader of lignin (47.11 % in PS + PN in 28 days) with maximum LME's production between 10th–17th days. Efficient lignin degradation in the PS and PN biomass will aid further application in pulp production supporting the transition to a circular economy in a greener way. [ABSTRACT FROM AUTHOR]

Commercial bamboo chips were pre-treated with sodium hydroxide (NaOH) solutions to completely extract silica and partially extract hemicelluloses prior to kraft pulping. Reaction temperatures of 80–100 °C, times of 1–5 h, and NaOH charges of 6–18% were explored. With increasing pre-extraction severity, all silica and up to 50% of hemicelluloses in raw chips could be extracted without degrading cellulose and lignin. The chips from select extractions were cooked using the kraft process with varying effective alkali (EA) charges. Pre-extraction resulted in significant improvement in the delignification of chips during subsequent kraft pulping, offering an option to reduce the EA charge or the H-factor. The pulp yield was similar to the control while the drainage resistance of pulp from pre-extracted chips was slightly improved. Physical strength properties of pulps made from pre-extracted chips showed lower tensile index and higher tear index as compared with the control runs. Moreover, silica was no more a problem for chemical recovery and production of high-grade pulp. Extracted silica and hemicelluloses in the alkaline extraction liquor (AEL) can be used as a potential raw material for value-added products. [ABSTRACT FROM AUTHOR]

This study compared oxidative delignification of birch kraft pulp fibers to pulp fibers from acid hydrotropic fractionation (AHF) using p -toluenesulfonic acid (p -TsOH). Under oxygen delignification at 20% consistency, AHF pulps with lower hemicellulose content showed higher delignification than kraft pulps with similar lignin content despite its residual lignin (cellulosic enzymatic lignin, CEL) being less reactive with fewer β-O-4 ether aryl linkages based on 2D13C-1H nuclear magnetic resonance (NMR) spectroscopy. The water retention value (WRV) of AHF pulp fibers, a measure of fiber accessibility to water or oxidative chemicals, was substantially greater than that of kraft pulp fibers. Similar comparison of various AHF pulps further suggested that fibers with lower hemicellulose content were easier to delignify (bleach) despite having more lignin with lower reactivity (fewer β-O-4 linkages). Additionally, the present study also indicated that oxygen delignification was more effective at high fiber consistency, which can be attributed to thinner water films on the fiber surfaces at higher fiber loadings. These results indicated that mass transfer was the rate controlling process in oxidative delignification of wood fibers. • Oxidative delignification is an environmentally sustainable process. • Oxidative delignification of fibers from kraft and acid hydrotropic pulping were compared. • Lignin reactivity was evaluated by the amount of β-O-4 ether linkages from 2D NMR. • Fiber accessibility was evaluated by water retention values and hemicellulose content. • Lignin accessibility was the rate controlling process. [ABSTRACT FROM AUTHOR]

The combination of hemicellulose pre-hydrolysis by dilute acid or steamexplosion followed by kraft pulping was one approach evaluated in this work to generate pulps from radiata pine wood chips amenable to saccharification by enzymatic hydrolysis. Dilute acid (combined severity factor, CS = 1.67) and steam explosion (severity factor, log Ro = 4.09) treatments were able to solubilize approximately 53% and 63% of the original hemicelluloses content in wood, respectively. Extracted wood chips were subjected to kraft cooking (170℃, 16-18% active alkali, 30% sulfidity and 1200 H-factor) to produce pulps that were further saccharified by cellulases. Lignin removal increased with increasing active alkali, affording delignification levels 28% for dilute acid and 68% for steam explosion extraction pretreatment pulps. Enzymatic digestibility of P. radiata pulps were low, and only samples pretreated by steam explosion reached glucan-to-glucose conversion near to 75%; this treatment was 31% and 37% higher than that obtained with wood chips that were pretreated by dilute acid extraction. [ABSTRACT FROM AUTHOR]

Depending on the production method, traditional paper mills often utilize the black liquor by burning it for energy. Hemicelluloses extracted from the raw material prior to pulping could be utilized to produce biochemical fuels. The aim of this study was to pre-extract hemicelluloses from wheat straw by treating the biomass with hot water and alkali (NaOH or the combination NaOH+NaBH4) at varying temperatures and chemical concentrations, and also to integrate resulting solid material to produce pulp and to produce bioethanol and biodegradable films from extracted liquor consisting mostly of xylan. Optimum hot water (135 °C) and alkali pre-extractions (16.7% NaOH at 50 ?C) removed 16.5% and 33.6% of the xylan from the straw structure, respectively. The liquid portion of the hot water (135 ?C) and alkali (16.7% NaOH at 50 ?C) pre-extracted oven-dry (OD) straw yielded up to 7.79% and 6.81% (g/100 g soluble material) ethanol. Good-quality biodegradable films were produced when some gluten and nanocellulose was added to the extracted xylan. Although the hot water pre-extracted pulp yield was slightly lower, its physical and mechanical pulp properties were comparable to those of the corresponding conventional soda pulp. [ABSTRACT FROM AUTHOR]

Extraction of hemicelluloses prior to pulping and conversion of the extracted hemicelluloses to other bioproducts could provide additional revenue to traditional pulp and paper industries. The effect of hemicelluloses pre-extraction with a hydrothermal (HT) process on Pinus radiata chemimechanical pulp (CMP) properties was investigated in this study. The HT extraction resulted in a release of 7% to 58% of the initial amount of hemicelluloses from the wood. The extraction yield increased with temperature and extraction time. This hemicellulosic fraction was in the form of low molar mass oligomers with molecular weights varying from 1.5 to 100 kDa. Compared with the control (unextracted) CMP pulp, the HT pre-extraction significantly reduced the refining energy to obtain a given fibrillation degree (freeness). The pulp yield with the HT/CMP process was in the range of 56% to 75%. Fiber properties of the pulps from pre-extracted wood, such as fiber length, were reduced, while increases in fiber width, fines content, fiber coarseness, and kink index were observed in comparison with the control pulps. The strength properties of CMP pulps decreased with increasing amounts of hemicellulose removal during the stage prior to pulping. [ABSTRACT FROM AUTHOR]

Kraft pulping was performed on bamboo residues and its impact on the chemical compositions and the enzymatic digestibility of the samples were investigated. To improve the digestibility of sample by degrading the xylan and lignin–carbohydrates complexes (LCCs), xylanase and α - l -arabinofuranosidase (AF) were supplemented with cellulase. The results showed more carbohydrates were remained in the samples pulped with low effective alkali (EA) charge, compared to conventional kraft pulping. When 120 IU/g xylanase and 15 IU/g AF were supplemented with 20 FPU/g cellulase, the xylan degradation yield of the sample pulped with 12% EA charge increased from 68.20% to 88.35%, resulting in an increased enzymatic saccharification efficiency from 58.98% to 83.23%. The amount of LCCs in this sample decreased from 8.63/100C 9 to 2.99/100C 9 after saccharification with these enzymes. The results indicated that degrading the remained xylan and LCCs in the pulp could improve its enzymatic digestibility. [ABSTRACT FROM AUTHOR]

The feasibility of using hardwood hemicellulosic pre-hydrolysate recovered from a dissolving pulping process for Acetone–Butanol–Ethanol (ABE) fermentation has been investigated. Dilutions and detoxification methods based on flocculation and nanofiltration were tested to determine the inhibitory concentration of phenolic compounds and to evaluate the efficiency of inhibitors removal on fermentation. Flocculation carried out with ferric sulfate was the most effective method for removal of phenolics (56%) and acetic acid (80%). The impact on fermentation was significant, with an ABE production of 6.40 g/L and 4.25 g/L when using flocculation or combined nanofiltration/flocculation respectively, as compared to a non-significant production for the untreated hydrolysate. By decreasing the toxicity effect of inhibitors, this study reports for the first time that the use of these techniques is efficient to increase the inhibitory concentration threshold of phenols, from 0.3 g/L in untreated hydrolysate, to 1.1 g/L in flocculated and in nanofiltrated and flocculated hydrolysates. [ABSTRACT FROM AUTHOR]

The spent liquor, SL, of neutral sulphite semi chemical pulping process contains lignosulfonate and hemicelluloses, but it is currently treated in the wastewater treatment of the process. This treatment decomposes the lignosulfonate. However, lignosulfonate can be extracted for a better use, but the extraction process is not an easy task. The main objective of this work was to extract lignosulfonate from SL via treating the SL with surfactant. The results showed that the acidification of SL to pH 1.8 caused 6% lignosulfonate, 53% hemicelluloses, and 7% COD removals from SL. Acidification followed by dodecyltrimethylammonium chloride, DTAC, treatment of SL at the optimal conditions of 22 °C, 1.8 pH and 10 mg/g of DTAC/SL yielded 40% lignosulfonate, 78% hemicelluloses, and 25% COD removals. Model solutions were prepared via dissolving commercial lignosulfonate and xylan in solutions or purifying SL via membrane dialysis in order to investigate the impact of SL components, i.e. hemicelluloses and residual cooking chemicals, on the isolation of lignosulfonate from SL. The model analyses confirmed that the presence of impurities, i.e. residual cooking salts, significantly affected the isolation of lignosulfonate from the SL, but the presence of hemicellulose had a minor effect in extracting lignosulfonate from SL via DTAC treatment. In addition, the elemental analysis confirmed that DTAC and lignosulfonate had a ratio of 0.584 mol/mol in precipitates. [ABSTRACT FROM AUTHOR]

The study determined and compared the yield, viscosity, and chemical and physical properties of the pulps obtained as a result of Alkaline Sulfite-Anthraquinone (AS-AQ) pulping of Caucasian spruce wood with and without the addition of sodium borohydride (ASAB process) and ethanol (ASAE). It was found that the addition of ethanol to the AS-AQ pulping had a favourable influence on the screened yield and kappa number of the pulps. The addition of NaBH4 to the AS-AQ pulping in general also had a favourable influence on these pulps' indices, provided that the amount added was not higher than 1-2% and the time of pulping was 180 mins. The higher yield of the ASAE pulps resulted from the higher retention of both cellulose and hemicelluloses, while the higher yield of ASAB pulps resulted from the higher retention of hemicelluloses and lignin. Regarding the AS-AQ pulping conditions, a distinct negative effect of modification on the viscosity of the pulps was observed in the case of the NaBH4 α additions to this pulping process. The viscosity reduction was, however, lower with extended pulping time. The static strength properties (tensile index and burst index) of the ASAB and ASAE pulps were in general lower than the AS-AQ pulps. In the case of the tear index, the tendency was similar . The addition of ethanol and especially NaBH4 to the AS-AQ pulping had a distinctly unfavourable influence on the whiteness and brightness of the pulps. [ABSTRACT FROM AUTHOR]

Wheat straw was subjected to three different processes prior to saccharification, namely alkaline pulping, natural pulping and autohydrolysis, in order to study their effect on the rate of enzymatic hydrolysis. Parameters like medium concentration, temperature and time have been varied in order to optimize each method. Milling the raw material to a length of 4 mm beforehand showed the best cost–value-ratio compared to other grinding methods studied. Before saccharification the pulp can be stored in dried form, leading to a high yield of glucose. Furthermore the relation of pulp properties (i.e. intrinsic viscosity, K lason -lignin and hemicelluloses content, crystallinity, morphology) to cellulose hydrolysis is discussed. [ABSTRACT FROM AUTHOR]

The pre-hydrolysis liquor (PHL) of the kraft-based dissolving pulp production process is currently sent to the recovery boiler and incinerated. However, PHL contains about 5-8% lignocelluloses that can be utilized in the production of value-added chemicals. In this study, a process for producing xylitol from hemicelluloses in PHL is developed. This process involves several acidification, neutralization, adsorption (along with reactivation) and evaporation stages. The mass balance indicates that 533kg/h xylitol (with 99% purity), 187kg/h lignin, 806kg/h basic ferric acetate, and 1600 kg/h gypsum can be produced from 41,670 kg/h PHL. The energy balance shows that the evaporators are the largest consumers of energy, while the reactivation kiln, acidification, neutralization, and precipitation processes generate some heat. Overall, 41% conversion of xylose to xylitol is achieved. [ABSTRACT FROM AUTHOR]

Highlights: [•] Choline acetate can dissolve hemicellulose and lignin in bagasse and pine. [•] Cellulose pulp is not dissolved during the dissolution of the other biopolymers. [•] The dissolved hemicellulose and lignin can be recovered after the dissolution. [•] The obtained pulp can be rapidly dissolved in 1-ethyl-3-methylimidazolium acetate. [Copyright &y& Elsevier]

Highlights: [•] The bacterium Paenibacillus glucanolyticus was isolated from black liquor. [•] P. glucanolyticus is a facultative anaerobe with optimum growth at pH 9 and 37°C. [•] This bacterium grows on black liquor, xylose, cellulose, hemicellulose and lignin. [•] Growth on black liquor produced malonic, succinic, gallic, and butyric acids. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new process enhances lignin removal from the prehydrolysis liquor was proposed. [•] Laccase treatment was incorporated into the new process. [•] Laccase treatment can polymerize low M w lignin. [•] The concentration of hemicelluloses and acetic acid were largely unaffected. [Copyright &y& Elsevier]

Pre-extracting part of hemicellulosesin wood can not only realizea high value-added utilization of hemicelluloses but also ensure theproduction of traditional pulping using the extracted wood raw materials,which benefits the highly efficient utilization of bioresources. Inthis work, this concept was applied to the poplar chemi-thermomechanicalpulping. The chemical components of the autohydrolysis liquor (AHL)at different autohydrolysis pretreatment conditions were studied,and the formation of acetic acid and its effect on the dissolutionof carbohydrate were also evaluated. The results show that the contentof the sugars (xylose, glucose, and arabinose), acetic acid, and furfuralincreased with the increase of autohydrolysis pretreatment temperatureand time, and the dissolved sugars in the AHL were mostly in a polymericform. The release of acetic acid played an important role in the dissolutionof carbohydrate and the pH value of the AHL. [ABSTRACT FROM AUTHOR]

Fractionation of lignocellulosic biomass is an important process in producing biofuels. In this study, hot water extraction of corn stover hemicellulose was carried out at 150, 160, and 170 °C. Variations of sugar content in the hydrolysate under different holding time were detected. The contents of furfural and 5-hydroxymethyl-2-furaldehyde generated during the extraction were also determined. Results showed that the main composition of the hydrolysate was xylo-oligosaccharide; the yield of oligosaccharides first increased as holding time was prolonged. After extraction at 160 °C for 210 min, 70.2% of the total xylan was dissolved, with the generation of furfural (0.90 g/L) and 5- hydroxymethyl-2-furaldehyde (0.10 g/L). The effects of extraction on alkali pulping and bleaching were also investigated. Results indicated that soda-AQ pulp obtained from the extracted material had poorer tensile and burst strengths but better tear strength. [ABSTRACT FROM AUTHOR]

Hemicelluloses and lignin present in the spent liquor (SL) of neutral sulfite semichemical (NSSC) pulping process can potentially be converted into value-added products such as furfural, hydroxymethylfurfural, levulinic acid, phenols and adhesives. However, the direct conversion of hemicelluloses and lignin of SL into value-added products is uneconomical due to the dilute nature of the SL. To have a feasible downstream process for utilizing lignocelluloses of SL, the lignocelluloses should initially be separated from the SL. In this study, an adsorption process (via applying activated carbon) was considered for isolating the dissolved lignin and hemicelluloses from the SL of an NSSC pulping process. Under the optimal conditions of pH, SL/AC weight ratio, time and temperature of 5.7, 30, 360 min and 30 °C, the maximum lignin and hemicellulose adsorptions were 0.33 and 0.25 g/g on AC. The chemical oxygen demand (COD) and turbidity of the SL were decreased by 11% and 39%, respectively, as a result of lignocellulose adsorption on AC. Also, the incineration behavior of the SL-treated AC was studied with a thermo-gravimetric analysis (TGA). [Copyright &y& Elsevier]

Highlights: [•] A concept was proposed to recover sugar and acetic acid from the PHL. [•] Activated carbon adsorption was applied to remove lignin. [•] NF and reverse RO were followed to recover and concentrate sugars and acetic acid. [•] Pressure and pH effect were also observed to optimize the process. [ABSTRACT FROM AUTHOR]

Highlights: [•] Steam explosion and steam pre-treatments were carried out before kraft pulping. [•] The rate of extraction of hemicelluloses was similar with both pre-treatments. [•] Steam explosion enhanced delignification more efficiently. [•] Pre-treatments reduced paper mechanical properties owing to the fiber morphology. [•] Paper optical properties were boosted when pre-treatments were carried out. [Copyright &y& Elsevier]

Highlights: [•] The contents of cellulose, hemicelluloses and lignin in the sugar cane bagasse fractions varied significantly. [•] The pre-hydrolysis soda process improves the xylan removal but decreases pulp yield. [•] The pre-hydrolysis soda pulping followed by ECF bleaching is adequate for producing dissolving pulp from depithed bagasse. [ABSTRACT FROM AUTHOR]

Hydrothermal treatments (HT) of birchwood were conducted at various intensities to extract the hemicelluloses before pulping. The amount of hemicellulosederived sugars in the hydrolysates, including xylulose, an isomerization product of xylose, reached first a maximum and then decreased with further increasing treatment intensity. The hydrolysates also contained furanic compounds, carboxylic acids, and a large variety of aromatics, the amounts of which were dependent on HT intensity. At high treatment intensities, furfural and acetic acid were the main products quantified. Numerous nonvolatile, low molar mass carboxylic acids were also formed, with 3-deoxypentonic acid being the most abundant. Additionally, almost 40 aromatic monomers and up to 30 dimers were detected. Syringaldehyde was the main monomer and syringaresinol was the main dimer. Some aromatic compounds could not be identified. The complexity of the hydrolysates, particularly after high-intensity HT, requires selective filtration and purification methods before the hydrolysates can be utilized in downstream processes. [ABSTRACT FROM AUTHOR]

The alkaline and acid preextraction of giant bamboo (Bambusa balcooa Roxburgh), grown in South Africa, before kraft and soda-anthraquinone (AQ) pulping was in focus and the effects of NaOH concentration, temperature, and time on hemicelluloses extraction were studied by means of a statistical experimental design. The NaOH concentration exerted the strongest influence, solubilizing up to 20.4% of the available xylan with 2.0 M NaOH at 90°C for 240 min. The optimal extraction condition was achieved with 1 M NaOH at 90°C for 240 min, in the course of which 13.6% of the xylan was removed; the screened pulp yield was 50.4% without viscosity reduction, whereas the burst index of the handsheets was even improved. In the case of dilute acid preextraction before soda-AQ pulping, 11.3% xylan could be removed without affecting the pulp quality. The viscosity of the pulp was even better than that of pulps from nonextracted bamboo. The biorefinery approach, alkaline preextraction in combination with kraft pulping, is superior to the approach, acid prehydrolysis/soda-AQ pulping. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cellulose was extracted from orange peel using soda–EDTA process. [•] Factorial experimental design and RSM were used to optimize the process parameters. [•] Extracted celluloses were characterized from the physico-chemical standpoint. [•] Pulping under the optimized conditions ended in low ash content cellulose materials. [ABSTRACT FROM AUTHOR]

Black spruce (Picea mariana) wood chips were subjected to enzymatic pretreatments, using an enzyme formulation containing cellulolytic and hemicellulolytic enzymes, combined with light mechanical treatments including downsizing and/or compression/decompression. These pretreatments were followed by 3 stages of mechanical refining in a lab-scale disc refiner. Depending on the treatment, the overall energy savings obtained could be as high as 15%. Most of the savings were obtained during the first stage of refining. Pulps collected after this stage were imaged using TEM and SEM. Differences were observed between differing treatment types. The most significant differences were seen when macerated chips were compressed and allowed to decompress in enzyme solutions. Enzyme treatments are able to change the rupture pattern during refining, thus lowering the overall specific energy consumption (SEC) as evidenced by improved pulp freeness and direct energy measurements. Increasing enzyme penetration helps to improve the overall SEC savings and also improves the distribution of energy savings throughout the refining stages by moving initial fiber separation from the middle lamella into the secondary wall. [ABSTRACT FROM AUTHOR]

The alkaline extraction of hemicelluloses from hardwoods prior to pulping, for further conversion to value-added products, seems to be a promising pathway for paper mills to increase profit and improve sustainability. However, the amount of hemicellulose extracted will be limited by the requirement to maintain pulp quality and pulp yield in comparison to existing pulping processes. The effects of NaOH concentration, temperature, and time on hemicellulose extraction ofEucalyptus grandiswere studied using a statistical experimental design. Extracted wood chips were subjected to kraft pulping to evaluate the effect of the extraction on cooking chemicals, pulp quality, and handsheet paper strengths. The selective xylan recovery (12.4% dry mass) fromE. grandiscombined with low-cooking, active alkali charge, and less cooking time advantaged the xylan extraction and subsequent modified kraft pulping process under the studied conditions. Pulp viscosity, breaking strength, and tensile index of handsheets were slightly improved. [ABSTRACT FROM PUBLISHER]

Highlights: [•] A lignin degradation bacterial consortium was screened from sludge of a reeds pond. [•] Approximate 60.9% lignin and 43.0% hemicelluloses, but 2.0% cellulose in reeds was degraded. [•] The consortium was consisted of cultured six isolates and uncultured bacteria. [•] It is feasible for the consortium to pulping by measuring physical characteristics of paper hand-sheets. [ABSTRACT FROM AUTHOR]

Highlights: [•] Novel method for cross-linking wood hemicelluloses was developed. [•] Increased molecular weight improves the mechanical properties of barrier films made of spruce galactoglucomannan. [•] Separation of pure hemicelluloses from those with bound aromatic moieties. [•] The method takes advantage of lignin–carbohydrate complexes. [•] Bound aromatic moieties in hemicelluloses can be used for cross-linking by employing laccase oxidation. [Copyright &y& Elsevier]