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Alpha-cellulose, a unique, natural, and essential polymer for the fiber industry, was isolated in an ecofriendly manner using eleven novel systems comprising recycling, defibrillation, and delignification of prosenchyma cells (vessels and fibers) of ten lignocellulosic resources. Seven hardwood species were selected, namely Conocorpus erectus, Leucaena leucocephala, Simmondsia chinensis, Azadirachta indica, Moringa perigrina, Calotropis procera, and Ceiba pentandra. Moreover, three recycled cellulosic wastes were chosen due to their high levels of accumulation annually in the fibrous wastes of Saudi Arabia, namely recycled writing papers (RWPs), recycled newspapers (RNPs), and recycled cardboard (RC). Each of the parent samples and the resultant alpha-cellulose was characterized physically, chemically, and anatomically. The properties examined differed significantly among the ten resources studied, and their mean values lies within the cited ranges. Among the seven tree species, L. leucocephala was the best cellulosic precursor due to its higher fiber yield (55.46%) and holocellulose content (70.82%) with the lowest content of Klasson lignin (18.86%). Moreover, RWP was the best α-cellulose precursor, exhibiting the highest holocellulose (87%) and the lowest lignin (2%) content. Despite the high content of ash and other additives accompanied with the three lignocellulosic wastes that were added upon fabrication to enhance their quality (10%, 11%, and 14.52% for RWP, RNP, and RC, respectively), they can be considered as an inexhaustible treasure source for cellulose production due to the ease and efficiency of discarding their ash minerals using the novel CaCO3-elimination process along with the other innovative techniques. Besides its main role for adjusting the pH of the delignification process, citric acid serves as an effective and environmentally friendly additive enhancing lignin breakdown while preserving cellulose integrity. Comparing the thermal behavior of the ten cellulosic resources, C. procera and C. pentandra exhibited the highest moisture content and void volume as well as having the lowest specific gravity, crystallinity index, and holocellulose content and were found to yield the highest mass loss during their thermal degradation based on thermogravimetric and differential thermal analysis in an inert atmosphere. However, the other resources used were found to yield lower mass losses. The obtained results indicate that using the innovative procedures of recycling, defibrillation, and delignification did not alter or distort either the yield or structure of the isolated α-cellulose. This is a clear indicator of their high efficiency for isolating cellulose from lignocellulosic precursors. [ABSTRACT FROM AUTHOR]

Three delignification treatments of corncob residues (CCR), including NaOH, formic acid, and sulfite treatments, were compared at the respective optimized condition and in light of chemical compositions, sugar recovery, and ethanol production. NaOH and sulfite treatment can remove lignin in the CCR efficiently. Though NaOH treatment showed a superior ability of delignification, its solid cellulose recovery is lower than that of sulfite treatment. The sulfite treatment has the highest selectivity between delignification and cellulose conservation. The formic acid-treated CCR still had high lignin contents because formic acid also accelerated the solvation of cellulose. In fed-batch simultaneous saccharification and fermentation (SSF) with 25% substrate loading, the highest 77.1 ± 2.33 g/L ethanol was from NaOH-treated CCR, corresponding to a CCR-to-ethanol yield of 0.208 ± 0.0021 g/g. However, the sulfite pretreated CCR also produced 68.2 ± 2.22 g/L ethanol, with a higher CCR-to-ethanol yield of 0.219 ± 0.0012 g/g. The high substrate dosage is beneficial to ethanol concentration but not beneficial to CCR-to-ethanol yield. The optimal substrate dosage required for ethanol production depends on the targeted aim (ethanol concentration or CCR-to-ethanol yield). [ABSTRACT FROM AUTHOR]

Sawdust, a major waste product of the forestry industry, is accumulating along the Lagos Lagoon in Lagos, Nigeria, without it being effectively managed. Besides its use in manufacturing sound-absorbing boards to reinforce concrete beams and for energy purposes, its potential as a renewable energy source and feedstock for bio-product development has not yet been realized. Cellulose, a glucose biopolymer and structural component of cellulose can be hydrolyzed by a hydrolytic enzyme known as cellulase. During the process, the enzyme breaks the B-1,4-glucosidic bond, which keeps the glucose units together, and by acting on this bond, numerous glucose units are released. As part of sawdust, the cellulose molecule is not freely available for the degradation action of the cellulase enzyme as it is strongly associated with lignin, which acts as bio-glue, keeping cellulose and hemicellulose together. Delignification is an effective technique that was used to make the sawdust from ten different trees along the Lagos Lagoon in Nigeria more susceptible to saccharification by cellulase isolated from the fungus Aspergillus niger. Delignified and non-delignified sawdust masses between 2 mg and 10 mg were incubated with the A. niger cellulase solution (2 mg.mL-1), whereafter, the amount of sugar produced by the cellulase action was determined. The percentage saccharification of each sawdust material was also linked with the amount of sugar produced during cellulase action. From these investigations was concluded that delignification increased sugar production when almost all the masses of different sawdust materials were degraded. It was also observed that the ratio of sawdust mass to enzyme concentration is an important variable that influences the effectiveness of the saccharification process. The percentage saccharification of the various sawdust materials was also determined, and it indicated that the highest percentage of saccharification was not obtained when the highest amount of sawdust was degraded, producing the highest amount of sugar. The saccharification of sawdust could contribute to the development of renewable energy sources and feedstock for bioproduct development. The process is, however, not that straightforward as variables such as the type of cellulase enzyme, pretreatment of the cellulose substrate, and optimizing of cellulase to cellulose ratio are a few that need to be optimized for the process to be effective in terms of glucose production. [ABSTRACT FROM AUTHOR]

The potential of oxygen delignified fibers to replace fully bleached fibers in tissue products was investigated on softwood pulps. The absorption, mechanical properties and softness of laboratory tissue hand sheets from one commercial fully bleached pulp and five unbleached oxygen delignified lab pulps were compared. The pulps with different lignin content and total fiber charge were evaluated with and without PFI refining. The pulps subjected to oxygen delignification resulted in pulps with much higher total fiber charge content that led to higher swelling and higher wet strength when compared to the commercial fully bleached pulp. Some unbleached oxygen delignified pulps showed great potential in the absorption capacity, while others showed a much higher wet tensile strength when compared to the commercial pulp. Compared to the commercial bleached pulp, a similar softness for a higher wet and dry tensile index in the unbleached fibers was observed for the oxygen delignified pulps. Unbleached pulps subjected to an extended oxygen delignification proved to be a suitable alternative to fully bleached pulps in tissue grades, depending on the desired property (absorption or wet strength). [ABSTRACT FROM AUTHOR]

This study investigated an ecofriendly peracetic acid delignification process to extract holocellulose from various fiber rich plant‐based byproducts (coconut palm spathe/leaf, apple pulp, wine grape pomace, hazelnut shell, and hemp fiber/hurd), and evaluated their physicochemical, morphological, and thermophysical properties in comparison with commercial cellulose nanofibers produced from wood. Holocellulose from coconut palm spathe has long fiber (~846.7 μm), whereas that from wine grape pomace and hazelnut shell exhibits a cylinder shape of particles with short fiber length (~123.8 and ~ 71.1 μm, respectively). Biofilms cast from apple pulp and hemp fiber holocellulose have higher degradation temperature (361 and 358°C, respectively) than biofilms from other materials, thus more thermally stable. All biofilms demonstrate high UV absorbance, and the biofilm cast from apple pulp holocellulose is transparent with smooth surface. Fourier‐transform infrared spectroscopy analysis confirms the presence of cellulose and hemicellulose as the main components in the biofilms, along with traces of residual lignin that remained after the extraction process. This study demonstrates that holocellulose with varied cellulose morphology and polymeric characteristics could be extracted depending on the type of byproducts and be employed to produce sustainable packaging materials. [ABSTRACT FROM AUTHOR]

Local evolution of delignification and xylan removal inside wood chips was investigated throughout the initial stages of kraft cooking. Model chips of birch sapwood were pulped at 145, 155 and 165 °C, utilizing white liquors with hydroxide content ranging from 0.25 to 0.55 mol/kg. The composition of different sections in each cooked sample was then determined. Xylan was isolated from selected samples and analyzed using size exclusion chromatography and HSQC NMR. Most changes in concentration and structure of residual xylan occurred early in the process (<45 min). Furthermore, xylan samples isolated from the tissue of different cooked chips had similar average molecular weights, indicating that temperature and alkali content had little impact over the extent of reactions affecting residual xylan. In contrast, xylan dissolution was significantly dependent on pulping conditions, increasing with hydroxide concentration. The lignin profile inside the cooked chips also varied with alkali content and temperature, and it was shown to be more uniform when applying low cooking temperatures (145 °C). Finally, increased delignification and xylan removal were detected close to the transverse surfaces of chips (likely due to the fast mass transport in vessels/lumen), implying that anatomical features of wood can have a significant impact on pulping. [ABSTRACT FROM AUTHOR]

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Cork, the outermost tissue of bark, plays an important role in protecting trees from the surrounding environment and is used for various purposes, including flooring and insulation materials for buildings. This study focused on the amount and distribution of hydrophobic substances such as suberin and lignin in cork, as well as moisture conditions, to understand the mechanical properties of Cerasus jamasakura cork. Strips of cork were subjected to tensile tests after exposure to various moisture conditions (water-saturated, air-dried and oven-dried), and also after the desuberinisation and delignification of specimens. Cork with a high moisture content showed significant strain to the tensile load, whereas oven-dried specimens showed little toughness. The increased toughness of cork at higher moisture contents was due to the continued elongation in the plastic region, especially in the inner cork. The fibre length of the highly deformed cork differed significantly before and after the tensile test. Tensile tests of cork after desuberinisation and delignification indicated that the removal of suberin caused an earlier reduction in tensile properties than the removal of lignin. The presence of suberin in cork, distributed mainly in the inner cork, is believed to affect the tensile properties of cork. [ABSTRACT FROM AUTHOR]

The most abundant natural renewable resource in the world, lignocellulosic biomass (LCB), has the potential to be exploited as a substitute green feedstock for the synthesis of various chemicals, materials, and biofuels. The annual global production of 13 billion tonnes of LCB offers an opportunity to cater to the increasing energy and materials requirement of process industries and also restricts the discharge of greenhouse gases. Although LCB is enriched with valuable ingredients such as cellulose, lignin, and hemicellulose, its recalcitrant nature limits its efficient utilisation. These components of LCB are strongly interlinked with each other, which resists their isolation and conversion valorisation into useful products. To disrupt the complicated structure of LCB and to isolate the lignocellulosic components in pure form, pretreatment is a crucial process in the bio-refinery, ensuring the economic feasibility of downstream processes. This review provides an outline of the structure, composition, and various sources of LCB; and the necessity of the pretreatment. Moreover, this article provides an in-depth analysis of the underlying mechanisms, advantages, and limitations of various pretreatment methods, such as physical, chemical, biological, and physicochemical. Further, the impact of chemical pretreatment techniques on the physicochemical characteristics of the material that is extracted from the biomass is also covered in detail through the rigorous evaluation of performance metrics, including substrate digestibility, sugar yield, inhibitor production, and energy requirements. This review provides a balanced and comprehensive overview of the state-of-the-art pretreatment strategies and their impact on biomass valorisation that will be useful to the scientists, engineers, and policy makers interested in biomass conversion technologies. [ABSTRACT FROM AUTHOR]

Compared with woody fibers, natural non-wood fibers also propose some advantages including more porous, fineness, low density, cheapness, and biodegradability. Without a doubt, the majority of the advancement in cellulose-based materials during the past few years has been the separation of microfibrils from plant sources. Among the agro-residual bast fibers, Helianthus annuus (sunflower) and Saccharum officinarum (sugarcane) are one of the most perceptible fiber crops with superior cellulosic substance. Decortication is the method followed to extract the fiber from the harvested plant stem. The extracted fiber from the plant stem was materialized and investigated after its surface modification by delignification through the kraft pulping process. The inorganic substances were removed from the cellulose fiber to reduce its toughness and to improve its soft, flexible, and liquid absorbency properties. The raw fiber and pulped microfibrils were analyzed under a scanning electron microscope (SEM) which finds the difference in their morphological structure. As beating and grinding of the fiber pulp for wet-laid nonwoven sheet formation were done and a free swell test for pulp was assessed for the absorbency property, it pertains good result ensemble for hygiene products such as cotton and wood pulp. [ABSTRACT FROM AUTHOR]

Timoho fiber (TF) has proven to be a potential reinforcement for composites due to its high cellulose content. Various efforts have been made to improve the TF performance in the composite fabrication, one of which is by making nanocellulose from the fiber. The structure can be the basic material for nanocomposites. Nanocellulose forms of fibers have good mechanical properties and lower density. Therefore, TF was prepared into nanocellulose by using effective methods of isolation and extraction. Fabrication process was done in three main stages namely extraction which was performed in three processes: dewaxing, mercerization, and delignification. Next, the cellulose was characterized using FTIR, XRD, FE-SEM. TEM, and TGA. Density and crystallinity index of TF nanocellulose were 0.52 g/cm3 and 88.47%. The TF morphology described the random structure which was adequate as nanocellulose method was effective to extract nanocellulose and is recommended as a sustainable cellulose bionanocomposite material. [ABSTRACT FROM AUTHOR]

Bark, the outermost tissue, plays an important role in protecting trees from damage induced by living organisms and the surrounding environment. Bark differs from the xylem primarily by the presence of suberin in cork cell walls. However, few studies have examined the role of suberin and its interactions with other chemical components in the cork. Consequently, this study aimed to understand the distribution of chemical components, including suberin and lignin, and their respective roles in cork cell walls, using Cerasus jamasakura (Siebold ex Koidz.) H. Ohba. Suberin and lignin were gradually and selectively removed from thin strip specimens. Fourier transform infrared (FTIR) spectroscopy suggested that desuberinization removed both suberin and part of the other matrix substances within a few minutes of treatment, whereas delignification exclusively removed lignin. Further microscopic observation revealed that suberin present was mainly in the secondary wall of cork cells, whereas lignin was present in both the tertiary wall and compound middle lamella. In addition, the cell wall collapse of the cork was only found in desuberinized specimens, whereas delignified specimens only showed monotonic contraction. Taken together, these results suggest that the presence of suberin in the cork contributes to the shape stability of cork cell walls. [ABSTRACT FROM AUTHOR]

The efficient exploitation of planted fast-growing wood is crucial for enhancing wood resource utilization. In this study, the fast-growing poplar wood was modified by in situ impregnation through vacuum impregnation with polyvinyl alcohol and nano-silica sol as impregnation modifiers, combined with delignification–freezing pretreatment. The samples were characterized by FTIR, XRD, SEM, and the universal mechanical testing machine. The results showed that the wrinkle deformation and cracking of the wood blocks were greatly alleviated after the delignification–freezing pretreatment and the polyvinyl alcohol and nano-silica sol were successfully integrated into the wood. The resulting polyvinyl alcohol–silica sol poplar composites exhibited about 216%, 80% and 43% higher compressive strength with respect to delignified wood, natural wood and impregnated natural wood, respectively, thereby demonstrating superior mechanical properties and potential opportunities for value-added and efficient utilization of low-quality wood. [ABSTRACT FROM AUTHOR]

Delignification has an important role in biomass utilization framework of Empty Fruit Bunch of Palm Oil (EFB). EFB from Sulawesi Island with high lignin reached 45% was a challenge. Innovation for delignification should be delivered to remove lignin but keep holocellulose, cellulose, and hemicellulose. Treated EFB improved accessible the holocellulose for subsequent process like enzymatic process. Delignification would remove or break down lignin to increase the accessibility. Delignification by ozonized NaOH solution conducted at ambient temperature to save energy and low NaOH concentration, 3.2%. Ozonization NaOH solution with 500 ppm H2O2 would produce hydroxyl radical (OH°), an oxydator. ORP, TDS, and TSS of black liquor was observed to assess any suspended and dissolved solid of EFB. Treated EFB was analized for its component, lignin, and holocellulose. At higher NaOH solution was the higher TSS in ozonized NaOH solution. The highest TSS by ozonized 0.8 M NaOH reached 50.810 ppm. Unfortunately, the holocellulose was also decomposed as well. Thus, the yield was decrease since both lignin and holocellulose degraded. Optimal delignification was figure out at 0.4 M or 1.6% NaOH whereas lignin decreasing and holocellulose increasing by 30.8% and 27.17%, respectively. XRD analysis clarified improvement of this delignification for crystallinity increased 8.5%, 69%, closer to α-cellulose. Morphology by SEM showed remove the impurities successfully and Si, Nb, Mg, and Ca detected by EDS. [ABSTRACT FROM AUTHOR]

The development of innovative processes for eco-friendly, yet efficient, wood pulping is required to achieve higher sustainability than traditional processes. In this study, the potential use of deep eutectic solvent (DES) and its aqueous solutions as delignification medium for eucalyptus pulping is evaluated. The effects of temperature and water content in the DES on the pulping process were investigated. Additionally, traditional kraft pulping was performed as a reference. The integration of water into DES could facilitate delignification and preserve carbohydrates, and the optimal result of choline chloride-lactic acid (ChCl-LA) aqueous solution with 20 vol% water pulping process achieved the highest pulp yield (60.11 ± 0.29%) with a lignin removal of 87.59 ± 0.78% at 140 °C. Further analysis revealed that the obtained pulp with a degree of polymerization of 1498 and a crystallinity of 69.79% exhibited better physical properties than kraft pulp. Meanwhile, 80.11 ± 0.80% of the initial lignin in wood with lower condensation degrees, more homogeneous molecular weight distribution, and higher purity than kraft lignin was recovered by sample precipitation with water. This study indicates that ChCl-LA aqueous solution (20 vol% water) is the potential wood pulping system and provides a great reference for the sustainable development of the pulp and paper industry. [ABSTRACT FROM AUTHOR]

Oil palm fruit mesocarp (OPFM) is a solid by-product containing cellulose, potentially serving as a raw material for biofuel. The cellulose content of this solid by-product can be extracted through delignification. Therefore, this study aimed to investigate the application of ozone for OPFM delignification to break down lignin bonds in the material. During the analysis, ozonolysis delignification was influenced by particle size, oxygen flow rate, and reaction time. Ozone flowrate analyzed using the Iodometric method. Cellulose, hemicellulose, and lignin content of raw material and treated samples were analyzed using the α -- cellulose, γ -- cellulose, and the Kappa method. The results showed that by using a particle size of 100 mesh, and a flow rate of 2 Lmin-1 for 15 min, ozone degraded 42.03% lignin, 15.89% hemicellulose, and concentrated 62.85% cellulose. SEM and FTIR results showed the removal of hemicellulose and lignin from OPFM with ozonolysis delignification. Furthermore, XRD analysis showed the crystallinity degree of the high cellulose yield. [ABSTRACT FROM AUTHOR]

Large quantities of hemp hulls can be completely utilized for creation of value-added products (cost effective biofuels and biochemicals) through a biorefinery approach. A sustainable approach in making xylose, a low calorie sweetener and high surface area activated carbons (AC) for super capacitors, attracts interest. The AC when leveraged as a co-product from biorefinery process makes it more cost effective and, in this paper, we discuss the production of xylose and AC from hemp seed hull with methane sulphonic acid (MSA) hydrolysis. Xylose recovery with MSA hydrolysis was 25.15 g/L when compared to the traditional sulphuric acid (SA) hydrolysis of 19.96 g/L at the same acid loading of 1.8 %. The scanning electron microscope (SEM) images and Fourier transform infrared (FT-IR) spectra indicate partial delignification along with hemicellulose hydrolysis responsible for high xylose recovery. Post hydrolysis fibers were KOH activated and carbonized to make AC. The MSA hydrolyzed and KOH activated fiber produced pure, fluffier and finer particle AC with a drastic increase in surface area 1 452 m2/g when compared to SA hydrolyzed of 977 m2/g. These results indicate the potential of MSA in dilute acid hydrolysis of biomass for xylose recovery and production of high surface area activated carbon. From a production standpoint this can lead to increased use of sustainable low-cost agricultural biomass for making high surface area AC as components in supercapacitors.

SPSW (sugar palm starch waste) was biomass that produce from processing of sugar palm starch. SPSW contain high cellulose, hemicellulose, and lignin. Using lignocellulose from sugar palm starch waste (SPSW) needs a pretreatment method to obtain high-purity cellulose and create an environmentally friendly method. The investigation focuses on determining the optimal NaOH concentration, temperature, and duration for hydrothermal-alkali treatment to remove hemicellulose and lignin, achieving high-purity cellulose. There is no further research regarding optimal conditions related to NaOH concentration, temperature, and duration for hydrothermal-alkali treatment to remove hemicellulose and lignin, achieving high-purity cellulose. This study aims to define optimal conditions for lignin and hemicellulose removal to obtain cellulose with high purity. The delignification process is carried out by hydrothermal and hydrothermal alkali activation. The hydrothermal activation removes hemicellulose, whereas the hydrothermal alkali activation removes lignin. In this study, Response surface methodology (RSM) was used to determine optimum conditions. The results were then structural and morphological identification using XRD, FTIR, and SEM. The optimization results obtained parameter values of 2% NaOH, temperature 120oC for 120 minutes. The desirability value was 0.774, with a response value of 2.9 ± 1.7% for hemicellulose, 92.35 ± 1.06% for cellulose, and 2.45 ± 0.1% for lignin. FTIR results showed that lignin was absent during the delignification process. Meanwhile, in XRD, during the delignification process, the crystallization index (CI) decreases, and the crystallization size (CS) increases. SEM analysis results show that the morphology of the delignified SPSW becomes smoother after pretreatment, which indicates a decrease in hemicellulose and lignin content and a high level of cellulose purity. Further research is needed on other parameters, such as cellulose yield, energy consumption, and environmental impact. This research should also consider other potential pretreatment factors, such as pressure and catalysts in the hydrothermal process

Sugar palm starch waste (SPSW) was biomass that produce from processing of sugar palm starch. SPSW contain high cellulose, hemicellulose, and lignin. Using lignocellulose from SPSW needs a pretreatment method to obtain highpurity cellulose and create an environmentally friendly method. The investigation focuses on determining the optimal NaOH concentration, temperature, and duration for hydrothermal-alkali treatment to remove hemicellulose and lignin, achieving high-purity cellulose. There is no further research regarding optimal conditions related to NaOH concentration, temperature, and duration for hydrothermal-alkali treatment to remove hemicellulose and lignin, achieving high-purity cellulose. This study aims to define optimal conditions for lignin and hemicellulose removal to obtain cellulose with high purity. The delignification process is carried out by hydrothermal and hydrothermal alkali activation. The hydrothermal activation removes hemicellulose, whereas the hydrothermal alkali activation removes lignin. In this study, Response surface methodology (RSM) was used to determine optimum conditions. The results were then structural and morphological identification using XRD, FTIR, and SEM. The optimization results obtained parameter values of 2% NaOH, temperature 120 °C for 120 minutes. The desirability value was 0.774, with a response value of 2.9 ± 1.7% for hemicellulose, 92.35 ± 1.06% for cellulose, and 2.45 ± 0.1% for lignin. FTIR results showed that lignin was absent during the delignification process. Meanwhile, in XRD, during the delignification process, the crystallization index (CI) decreases, and the crystallization size (CS) increases. SEM analysis results show that the morphology of the delignified SPSW becomes smoother after pretreatment, which indicates a decrease in hemicellulose and lignin content and a high level of cellulose purity. Further research is needed on other parameters, such as cellulose yield, energy consumption, and environmental impact. This research should also consider other potential pretreatment factors, such as pressure and catalysts in the hydrothermal process. [ABSTRACT FROM AUTHOR]

Biomass pretreatment is essential to facilitate lignin removal and enhance cellulose concentration for optimal bioethanol production. Therefore, this research aimed to determine the effects of conventional KOH (KP) and Combined KOH microwave-assisted (CKMP) pretreatment on the banana stem (BS) composition, analyzing the kinetics of lignin removal at various temperatures and KOH concentrations for 25 min. Kinetics variables were calculated by fitting experimental data and cellulose was hydrolyzed to produce reducing sugars. The results showed that the highest lignin removal for KP and CKMP were 37.11%, and 40.39%, respectively, with CKMP having the lowest activation energy of approximately 2.688 kJ mol−1. CMCase and FPase activity were 1988.3474 and 1605.4187 U mL−1, respectively, which were significantly higher than the values reported in previous research. The maximum concentration of reducing sugars achieved was 17.69 g L-1, with an enzyme concentration of 50% (v/w), pH 5, and a hydrolysis duration of 25 h. Michaelis constant varied from 0.0037 to 0.0079, and the maximal rate ranged from 1.28 × 10−6 to 2.76 × 10−6 Mol L−1 s−1 when computing the reaction rate using the Michaelis–Menten kinetics model. [Display omitted] • The results of this study provided insight into producing bioethanol from banana stems. • Combined KOH microwave-assisted pretreatment (CKMP) of banana stem was carried out. • Lignin content was effectively removed at 43.02%. • Enzymatic hydrolysis kinetics followed the Michaelis–Menten kinetics model. • K M value was 0.0037–0.0079 and v max was 1.28 × 10−6 to 2.76 × 10−6 Mol L−1 s−1. [ABSTRACT FROM AUTHOR]

Abstract Oil palm trunk (OPT) is an inexpensive, abundantly available by-product of palm oil production which is typically not put to material use. Due to its comparably high cellulose content, OPT represents a suitable raw material for the preparation of cellulose nanofibrils (CNFs). Aiming for full utilization of the raw material and minimized energy demand, non-delignified and partially delignified (alkali-pretreated) OPT was subjected to mechanical fibrillation in the present study. As compared to CNFs from fully delignified OPT, the lignin-rich microfibrils obtained by this approach generally showed higher average fibril diameters, lower thermal stability as well as lower viscosity, and higher sedimentation rate in suspension. However, the combination of alkali-pretreatment and fibrillation by disc-grinding and subsequent high-pressure homogenization resulted in fibrils with properties similar to those of CNFs from fully delignified OPT. As proven by IR-spectroscopy, thermogravimetry and chemical composition analysis, alkali-treated OPT fibrils still contained substantial amounts of residual lignin which could, for instance, act as a natural coupling agent or binder in composite applications. Moreover, the facile delignification process applied herein requires far less chemicals and energy than conventional pulping and is thus beneficial from both the economic and ecological perspective.

The reactivity during enzymatic hydrolysis of eight industrially produced samples of pulps and semichemical pulps by enzyme preparations of glycosyl hydrolases B151 and F10 produced by a strain of the ascomycete fungus Penicillium verruculosum has been determined. It is shown for the first time that among fibrous pulps available on the market of pulp and paper industry in Russia, the highest level of yield of glucose from the initial wood during biocatalysis using cellulases and hemicellulases is characteristic of semichemical pulps obtained after green liquor cooking of hardwood. A high degree of enzymatic conversion of softwood bleached kraft pulp has been established, which in combination with the possibility of obtaining modified polysaccharide materials from non-hydrolysable residue makes this cellulosic substrate the most promising for the development of biological processes at pulp and paper industries. It is shown that drying of pulp negatively affects the efficiency of cellulose hydrolysis, while mechanical refining improves the performance of the enzymatic saccharification process. [ABSTRACT FROM AUTHOR]

Delignification, recently much used in wood modification and functional material preparation, is closely related to wood-water interactions. To attain more information on the role of delignification in wood, this study characterized the water state changes during water-absorption and air-drying process with LF-NMR. By adjusting delignification time, lignin was removed about 15%, 34%, and 61%, respectively. Water absorption increased after delignification, and free water was generated more and faster than bound water. This was because delignification changed wood-water interaction environments suggested by SEM and FTIR analysis. Specifically, delignification increased hygroscopic polysaccharide percentage and sorption site concentration. New pore generation and enlargement after delignification provided more water exchanging paths and accommodation. Besides, delignified wood had higher and faster moisture decrease, and wood air drying was facilitated because of enriched water exchanging paths and higher initial moisture gradient difference in water-saturated delignified wood. Therein, free water decreased more and faster than bound water. The T2s of bound water and free water were both shortened after delignification, indicating water had tighter intermolecular interaction with delignified wood. The study provided new insight for understanding the role of lignin in water state changes during wood-water interactions and may facilitate better preparation of functional material and wood modification. [ABSTRACT FROM AUTHOR]

Sawdust, a product of the forest industry is mostly left untreated as solid waste. This phenomenon is well observed along the Lagos Lagoon in Nigeria where hundreds of trees are cut daily by sawmills to deliver wood for mainly the furniture industry. Different types of trees are utilized in this manner and the massive amounts of sawdust produced as a result of these activities are polluting the environment causing health risks for humans and animals. Cellulose, a glucose bio-polymer is a major structural component of sawdust and could be developed as a renewable energy resource should the cellulose be degraded into glucose, a fermentable sugar. This saccharification was done with Aspergillus niger cellulase and to make the cellulose more susceptible for cellulase action the sawdust was delignified with hydrogen peroxide. Both delignified and non-delignified sawdust were treated with the cellulase enzyme at incubation temperatures of 30°C, 40°C, 50°C, and 60°C. Delignification proved to be effective as an increased amount of sugar was released from all delignified sawdust materials relative to the non-delignified materials when saccharified with A. niger cellulase. Most of the materials were degraded at an incubation temperature of 40°C and 50°C and the highest percentage saccharification of 58% was obtained during the degradation of delignifed cellulose from the tree, Ricindendron heudelotti [ABSTRACT FROM AUTHOR]

The densification of solid wood is a well-studied technique that aims to increase the strength and hardness of the material by permanently compressing the wood tissue. To optimise the densification process in this study, a pre-treatment with sodium sulphite was used (delignification). With delignification prior to densification, one achieves higher compression ratios and better mechanical properties compared to densification without pre-treatment. The reactivity of syringyl (dominant in hardwoods) and guaiacyl (dominant in softwoods) lignin towards delignification is different. The influences of this difference on the delignification and densification of softwoods and hardwoods need to be investigated. This study aimed to densify wood after delignification and investigate how variations in chemical composition between coniferous and deciduous species affect the densification process. Scots pine and Eurasian aspen specimens with a similar initial density were investigated to study the influence of the different lignin chemistry in softwoods and hardwoods on the densification process. Both timbers were delignified with sodium sulphite and sodium hydroxide and subsequently densified. While the delignification was twice as efficient in aspen than in pine, the compression ratios were almost identical in both species. The Brinell hardness and compressive strength showed a more significant increase in aspen than in Scots pine; however, one exception was the compressive strength in a radial direction, which increased more effectively in Scots pine. Scanning electron microscopy (SEM) revealed the microstructure of densified aspen and Scots pine, showing the crushing and collapse of the cells. [ABSTRACT FROM AUTHOR]

Delignification and fractional pretreatments are essential for valorization of wood biomass in various bioproducts. Herein, lignocellulose wood fibers were exposed to a eutectic mixture (EM) of carvacrol and methanesulfonic acid for different times. The resulting structural and chemical alterations in biomass were explored in terms of the fiber morphology and fractional chemical composition through fiber image analysis, field-emission scanning electron microscopy, high-performance liquid chromatography, and a novel approach based on fluorescence-lifetime imaging microscopy (FLIM). The autofluorescence of the lignocellulose fibers, which was primarily due to lignin with contributions from cellulose and hemicellulose, enabled application of FLIM in lignocellulose compositional analysis in micro-scale. FLIM analysis revealed that EM treatment efficiently removed lignin from the outer fiber layers. Furthermore, the effective EM treatment time was 3 h (with a residual lignin content of ~ 7 wt%), after which defects were observed on the fibers and the cellulose chains started breaking. This degradation was also indicated by a shift of the lifetime spectra toward the fluorescence lifetime of cellulose with increasing treatment time. Overall, our findings provide valuable insights to the response of lignocellulose fibers to EM treatment, contributing to the important goal of wood biomass application in bioproducts. [ABSTRACT FROM AUTHOR]

The wheat straw delignification condition influence in the medium "acetic acid-water-hydrogen peroxide-citric acid catalyst" to the yield and cellulose product composition was studied. It was established that the fibrous semi-finished product output and the residual lignin content are decrease with increasing temperature and delignification duration. The oxidative wheat straw delignification process was described by a first-order kinetic equation, and it was characterized by low activation energy values of 16.7 kJ mol-1. The oxidized cellulose sample's structure was studied using IR spectroscopy. [ABSTRACT FROM AUTHOR]

In the present study, cellulose was effectively separated from eucalyptus wood with ternary solvents containing organic base 1,1,3,3-tetramethyl guanidine and other organic solvents such as morpholine, N-ethyl morpholine, dimethyl formamide, glycerin, ethylene glycol and diethylene glycol. It was found that the combination of 1,1,3,3-tetramethyl guanidine with morpholine was favorable for achieving high delignification and less loss of cellulose. The removal of lignin and hemicellulose achieved 89.8% and 81.4% after heating for 6 h at 160 °C, respectively. It was found that the combination of 1,1,3,3-tetramethyl guanidine with morpholine was favorable for achieving high delignification and less loss of cellulose. The removal of lignin and hemicellulose achieved 89.8% and 81.4% after heating for 6 h at 160 °C, respectively. The addition of morpholine and water promoted the dissolution of lignin and reduced the degradation of cellulose. Subsequently, the crude cellulose was further purified through a simplified bleaching process, the final removal of lignin and hemicellulose increased to 98.7% and 97.5% respectively, and cellulose with a purity of 96.9% was achieved. The scanning electron microscopy analysis indicated that the diameter of cellulose bundles decreased from about 250 μm to about 20 μm after organic solvents treatment. The fiber bundle was completely separated into a single fiber with a diameter of about 5–10 μm after bleaching process. X-ray diffraction analysis revealed an increase in the crystallinity of fiber from 69.4% to 83.3%, implying a reduction of lignin and hemicellulose in eucalyptus. Fourier transform infrared spectra revealed the high selective removal of lignin and hemicellulose. Two-dimensional 1H-13C Heteronuclear singular quantum correlation was performed to investigated the structure units and linkages of lignin and found that only the structural signal of C5-H5 in guaiacyl (G5) alone existed in the aromatic region, while the signals -OCH3, Cγ–Hγ in β-O-4' (Aγ) and β-β' (Cγ) remained in the side chain region, indicating that lignin could be effectively degraded and dissolved by the ternary solvents. In conclusion, high purity cellulose was obtained from eucalyptus wood by environmentally friendly and recyclable processes. [ABSTRACT FROM AUTHOR]

This work demonstrates an additive and hydrogen‐free 2‐step lignin‐first fractionation in flow‐through. First, solvolytic delignification renders lignin liquors with its native chemical structure largely intact; and second, ß‐zeolite catalytic depolymerization of these liquors leads to similar monomer yields as the corresponding 1‐step fractionation process. Higher delignification temperatures lead to slightly lower ß−O−4 content in the solvated lignin, but does not affect significantly the monomer yield, so a higher temperature was overall preferred as it promotes faster delignification. Deposition of Pd on ß‐zeolite resulted in a bifunctional hydrogenation/dehydration catalyst, tested during the catalytic depolymerization of solvated lignin with and without hydrogen addition. Pd/ß‐zeolite displays synergistic effects (compared to the Pd/γ‐Al2O3 and ß‐zeolite tested individually and as a mixed bed), resulting in higher monomer yield. This is likely caused by increased acidity and the proximity between the metallic and acid active sites. Furthermore, different ß‐zeolite with varying SAR and textural properties were studied to shed light onto the effect of acidity and porosity in the stabilization of lignin monomers. While some of the catalysts showed stable performance, characterization of the spent catalyst reveals Al leaching (causing acidity loss and changes in textural properties), and some degree of coking and Pd sintering. [ABSTRACT FROM AUTHOR]

Current DES pretreatment is often performed under relatively severe conditions with high temperature, long time, and high DES usage. This work studied a short‐time diol DES (deep eutectic solvent) pretreatment under mild conditions to fractionate the bamboo, facilitate enzymatic hydrolysis, and obtain high‐quality lignin. At an optimized condition of 130 °C for only 10 min, lignin and xylan removal reached 61.34 % and 84.15 %, with residual glucan showing a ~90 % enzymatic hydrolysis yield. Equally important, the dissolved lignin could be readily recovered with 97.51 % yield, exhibiting 96.65 % β‐O‐4 preservation. The fractionation and lignin protection mechanisms were unveiled by XRD, FTIR, cellulose‐DP, 2D HSQC NMR, 31P NMR and GPC analysis. This study highlighted that short‐time fractionation of bamboo can be achieved by a diol‐based DES which is an ideal strategy to upgrade the lignocellulose biomass for high enzymatic hydrolysis yields and high‐quality lignin stream. [ABSTRACT FROM AUTHOR]

Alkaline pretreatment stands out as a valuable strategy in biomass conversion to overcome the recalcitrance of biomass by removing lignin and a part of hemicellulose. This enhances enzyme accessibility and promotes saccharification. However, increasing the alkaline concentration to enhance the delignification and improve glucose yield together presents inherent limitations. In this experiment the amount of delignification and glucose yield resulting from surfactant associated with sonication during mild alkaline pretreatment of Eucalyptus pellita was investigated. Also, the effect of various factors (sonication temperature and surfactant immersion time) on delignification and glucose yield were examined. The results demonstrated that surfactant associated with sonication pretreatment could overcome the limitation of alkaline pretreatment and could increase the amount of delignification alongside enzymatic hydrolysis glucose yield of Eucalyptus pellita wood by around 90%. The findings indicated that surfactant-assisted with sonication during mild alkaline pretreatment of Eucalyptus pellita (i.e., hardwood) could be recommended as a supporting pretreatment method for the production of monomeric sugars. [ABSTRACT FROM AUTHOR]

Wood is a natural composite widely employed as a residential building interior finishing. Although wood is readily available and offers benefits to the occupants, such as enhanced well-being, it is rarely employed in commercial construction due, amongst others, to the potential hazard of fire propagation. The application of flame retardant (FR) treatments leads to a reduction of wood flammability and supports wood as interior finishing. Polyelectrolyte complexes (PECs) deposition is an innovative surface treatment that has already proven its efficiency for fabrics. For wood, recent studies have highlighted that the weight gain impacted the fire-retardancy, and a minimum of 2 wt.-% was set to obtain fire protection. This study explored the potential of surface delignification to activate the wood surface and facilitate the PEC impregnation. Yellow birch (Betula alleghaniensis, Britt.) was surface delignified (0.3 mm) using sodium chlorite. The treatment impact on wood was evaluated by spectroscopy analysis (FTIR, Raman), and the increase in wood wettability was demonstrated (contact angle decreases from 50° to 35° after the surface delignification). Then, PECs consisting of polyethyleneimine and sodium phytate were surface impregnated in wood and delignified wood. The flame retardancy was evaluated using a cone calorimeter. Despite the increase in weight gain (1.5 wt.-% ± 0.3 wt.-% to 4.3 wt.-% ± 2.5 wt.-%), fire performance was not improved. This study demonstrates that lignin strongly affects char formation, even in the presence of PECs. [ABSTRACT FROM AUTHOR]

Sugarcane (Saccharum officinarum) bagasse (SCB) is one of the most widely produced lignocellulosic biomasses and has great potential to be recycled for sustainable food production as ruminant animal feed. However, due to severe lignification, i.e., lignin-(hemi)-cellulose complexes, ruminants can only ferment a minor fraction of the polysaccharides trapped in such recalcitrant lignocellulosic biomasses. This study was therefore designed to systematically evaluate the improvement in nutritional value, the in vitro dry matter digestibility (IVDMD), and the rate and extent of in vitro total gas (IVGP) and methane (CH4) production during the 72 h in vitro ruminal fermentation of SCB, bioprocessed with Agaricus bisporus, Pleurotus djamor, Calocybe indica and Pleurotus ostreatus under solid-state fermentation (SSF) for 0, 21 and 56 days. The contents of neutral detergent fiber, lignin, hemicellulose and CH4 production (% of IVGP) decreased (p < 0.05), whereas crude protein (CP), IVDMD and total IVGP increased (p < 0.05) after the treatment of SCB for 21 and 56 days with all white-rot fungi (WRF) species. The greatest (p < 0.05) improvement in CP (104.1%), IVDMD (38.8%) and IVGP (49.24%) and the greatest (p < 0.05) reduction in lignin (49.3%) and CH4 (23.2%) fractions in total IVGP were recorded for SCB treated with C. indica for 56 days. Notably, C. indica degraded more than (p < 0.05) lignin and caused greater (p < 0.05) improvement in IVDMD than those recorded for other WRF species after 56 days. The increase in IVGP was strongly associated with lignin degradation (R2 = 0.72) and a decrease in the lignin-to-cellulose ratio (R2 = 0.95) during the bioprocessing of SCB. Our results demonstrated that treatment of SCB with (selective) lignin-degrading WRF can improve the nutritional value and digestibility of SCB, and C. indica presents excellent prospects for the rapid, selective and more extensive degradation of lignin and, as such, for the improvement in nutritional value and digestibility of SCB for ruminant nutrition. [ABSTRACT FROM AUTHOR]

Aims: This study was aimed to characterize laccase from a selected fungal strain and examine the enzyme’s ability to remove lignin from paper pulp. Methodology and results: Twelve fungal strains were screened for laccase production, resulting in the selection of Trichoderma sp. UBDFT12. The highest laccase activity (103 U/L) was observed from the culture filtrate on the fourth day of incubation. The optimum temperature and pH for the enzyme were 40 °C and pH 4, respectively. However, the enzyme stability was found to be reduced with time after 1 h incubation. At 1 mM, it was found that AgNO3, CaCO3, CuSO4, KCl, MgSO4, MnSO4 and ZnSO4 increased the laccase activity to 107, 107, 111, 112, 106, 105 and 107%, respectively, whereas FeSO4 and NH4Cl reduced the activity to 84 and 99%, respectively. The addition of 1% H2O2, 1% NaCl, 1% sodium dodecyl sulphate (SDS), 1 mM ethylenediaminetetraacetic acid (EDTA), 10 mM EDTA, 1 mM phenanthroline and 10 mM phenanthroline reduced the activity to 95, 73, 0, 79, 79, 73 and 37%, respectively. The culture filtrate was partially purified via ammonium sulphate precipitation and the recovered enzyme had a specific activity of 0.176 U/mg. Using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), the molecular weight of the enzyme was approximately 65 kDa and its activity was confirmed by zymography. The culture filtrate was also found to be able to remove lignin from different types of paper pulp. Conclusion, significance and impact of study: Laccase produced by Trichoderma sp. UBDFT12 was found to have the ability to remove lignin from paper pulp. [ABSTRACT FROM AUTHOR]

The persistent expansion in world energy and synthetic compounds requires the improvement of renewable alternatives in contrast to non-sustainable energy wellsprings. Lignocellulose is an encouraging feedstock to be utilized in biorefineries for its conversion into value-added products, including biomaterials, biofuels and several bio-based synthetic compounds. Aside from all categories, biofuel, particularly bioethanol is the most substantial fuel derived from lignocellulosic biomass and can be obtained through microbial fermentation. Generally, extreme settings are required for lignocellulosic pretreatment which results in the formation of inhibitors during biomassdegradation. Occasionally, lignin polymers also act as inhibitors and are left untreated during the pretreatment, engendering inefficient hydrolysis. The valorization of lignocellulosic biomass by laccases can be viewed as a fundamental trend for improving bioethanol production. However, one of the main obstacles for developing commercially viable biofuel industries is the cost of enzymes, which can be resolved by utilizing laccases derived from microbial sources. Microbial laccases have been considered an exceptionally integral asset for delignification and detoxification of pretreated LCB, which amplify the resultant fermentation and saccharification processes. This review provides a summary of microbial laccases and their role in valorizing LCB to bioethanol, compelling enthralling applications in bio-refining industries all across the globe.

Palm oil processing in the industry produces products and waste; the waste generated from the palm oil processing process will have a negative impact on the environment if it is not processed. Oil palm empty fruit bunches are lignocellulosic solid wastes that contain cellulose, lignin, and hemicellulose content, so they have the potential to be raw materials for making bioethanol. In the process of producing bioethanol, delignification is an early stage that aims to reduce the lignin content in lignocellulosic materials with alkaline or alkaline pretreatment solutions such as the use of NaOH can be used to help separate lignin from cellulose fibers. This study aimed to analyze the effect of NaOH concentration and delignification temperature on the lignocellulosic content of oil palm empty fruit bunches. The research method was arranged descriptively with two treatments: the concentration of NaOH consisting of 3%, 4%, and 5%, and the heating temperature consisting of 100 oC, 110 oC, and 120 oC. Lignocellulosic content can be calculated using the Chesson method analysis with the Microsoft Excel 2016 application as a data processor. The results showed that 1 M NaOH concentration with heating temperature had an effect on the observations of hemicellulose, cellulose, and lignin. The best treatment of 1 M NaOH concentration and heating temperature on hemicellulose, cellulose, and lignin was produced by the treatment of 5% NaOH concentration with a heating temperature of 120 0C.

Due to their cost-effectiveness and environmentally friendly nature, deep eutectic solvents (DESs) hold great potential for applications in biomass conversion and the production of green chemicals. In this study, the delignification of the stone pine (Pinus pinea L.) cone was performed using seven different ternary deep eutectic solvents (TDESs). TDES treatments of stone pine cone samples were carried out in a microwave for 30 min. at 150 °C. The two-based components of TDESs were choline chloride (ChCl - 1 mol) and lactic acid (LA - 9 mol). The formic acid (FA – 2 mol), boric acid (BA – 1 mol), acetic acid (AA – 2 mol), sorbitol (S – 1 mol), triethylene glycol (TEG – 2 mol), ethylene glycol (EG – 2 mol), and glycerol (G – 2 mol) were used as third component of TDES. ChCl:LA:BA gave the lowest solid residue yield (57.90%) and highest lignin purity (86.89%). Klason lignin content of control was 35.08%. The lowest lignin content (19.42%) and highest delignification (68.89%) were obtained with ChCl:LA:FA treatment. The lowest and the highest L* values were obtained from ChCl:LA:BA and ChCl:LA:EG treatments with 21.76 and 37.36, respectively. This results showed that the third component of TDES affects the delignification efficiency of stone pine cone.

Wood is a natural composite material mainly consisting of three components, i.e., cellulose, hemicellulose, and lignin. It exhibits a complex hierarchical structure characterized by open channels, aligned in the growth direction, having specific porosity at micro-, meso-, and macro-scale, and an extended opacity, due to adsorption phenomena because of the presence of lignin and scattering, as different refractive indexes characterize its components. Even if during the historical ages some of its applications have been replaced by other materials, wood still covers a large part of common uses, which range from biomass for energy recovery to material for the building sector, or from artifacts to household/furniture manufacturing. Despite its real invention dating to 1992, only about ten years ago two independent research groups, one from the University of Maryland (USA) and the other from the Royal Institute of Technology (Sweden) rediscovered and started to thoroughly investigate the so-called transparent wood (TW). TW can be derived from almost any wood biomass through specific chemical treatments focused on lignin. These aim to completely remove this component from wood or to eliminate the chromophore groups present in the pristine material, hence obtaining, after direct densification or after infiltration with a suitable polymer resin, a new material with very high transparency, toughness, and lightness. These characteristics can further be combined with other specific features (such as environmental protection, flame retardancy, photoluminescence, and energy storage ability, among others), which open the way toward the development of new, up-to-date, advanced, and sustainable materials for both structural and functional purposes, fulfilling the current concepts of circular economy and sustainability. The present review is aimed at providing the reader with an overview of the characteristics of transparent wood, describing the latest applications and, finally, discussing some challenging issues and perspectives for possible developments in the forthcoming years.