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1
Paszner, Laszlo, et H. J. Cho. « High Efficiency Conversion of Lignocellulosics to Sugars for Liquid Fuel Production by the ACOS Process ». Energy Exploration & ; Exploitation 6, no 1 (février 1988) : 39–60. http://dx.doi.org/10.1177/014459878800600104.
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Decline of world oil reserves and pollution problems from burning of fossil fuels and lead require that methods for safe alternate liquid fuels be developed. Ethanol is one of the most important alternate liquid fuels since it can be produced readily by fermentation of sugars. Wood and vegetable growth are excellent sources of sugars to support an ethanol fuel economy of significant proportions. Acid Catalysed Organosolv Saccharification (ACOS) is a new means for total biomass dissolution and recover of component sugars and lignin from wood. The process uses an acidified aqueous acetone solution for the high-temperature hydrolysis of biomass. Acetone provides an excellent reaction medium for dissolution of both sugars and lignins and through a transient derivatization of the sugars protects them from further reaction (dehydration) to furfurals and humic substances. Therefore, sugar and lignin recoveries are quantitative. The ACOS process is 700 times faster than the conventional weak acid hydrolysis processes and wood can be dissolved in 30 sec by this process. The lignin is recovered as a low molecular weight powder by-product. This process is applicable to both coniferous and deciduous woods and agricultural residues such as corn stover, straw and bagasse. In case of such residues the ethanol yield can be doubled (straw and corn stover) or tripled (bagasse) compared to what has been obtained from the grain and sugarcane juice so far. Hitherto these residues were merely discarded or burned.
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Tian, Guoyu, Yaqi Chu, Xiaoqian Chen, Xiuhong Zhong, Zhaojiang Wang et Tongtong Zhang. « Separation and characterization of lignin and sugars in the hydrolysate of hot water extraction of poplar wood by membrane filtration and activated carbon adsorption ». BioResources 16, no 4 (5 août 2021) : 6613–28. http://dx.doi.org/10.15376/biores.16.4.6613-6628.
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Hot water extraction of poplar wood was conducted at temperatures from 190 to 200 °C for 5 to 8 min. A hemicellulose yield of 81% and a lignin yield of 38% were obtained at 200 °C for 8 min. A combined process of microfiltration, ultrafiltration, and activated carbon adsorption was developed to separate lignin and sugars in the hydrolysate of hot water extraction. Lignin recovery efficiencies of 56.7%, 26.0%, and 13.2% were attained for microfiltration, ultrafiltration, and activated carbon adsorption, respectively. The characterization of lignin revealed diversity in molecular weight and functional groups, which is beneficial for high-value valorization. The obtained hemicellulose sugars from the combined process showed a good recovery rate of 43.8% and remarkable purity of 97.5%. The purified sugars were a mixture of monomers and oligomers that consisted of arabinose, galactose, xylose, glucose, and mannose. Sugar oligomers with degrees of polymerization from 2 to 6 accounted for 21.6% of all sugars.
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Serna-Loaiza, Sebastian, Manuel Dias, Laura Daza-Serna, Carla C. C. R. de Carvalho et Anton Friedl. « Integral Analysis of Liquid-Hot-Water Pretreatment of Wheat Straw : Evaluation of the Production of Sugars, Degradation Products, and Lignin ». Sustainability 14, no 1 (30 décembre 2021) : 362. http://dx.doi.org/10.3390/su14010362.
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Developing sustainable biorefineries is an urgent matter to support the transition to a sustainable society. Lignocellulosic biomass (LCB) is a crucial renewable feedstock for this purpose, and its complete valorization is essential for the sustainability of biorefineries. However, it is improbable that a single pretreatment will extract both sugars and lignin from LCB. Therefore, a combination of pretreatments must be applied. Liquid-hot-water (LHW) is highlighted as a pretreatment for hemicellulose hydrolysis, conventionally analyzed only in terms of sugars and degradation products. However, lignin is also hydrolyzed in the process. The objective of this work was to evaluate LHW at different conditions for sugars, degradation products, and lignin. We performed LHW at 160, 180, and 200 °C for 30, 60, and 90 min using wheat straw and characterized the extract for sugars, degradation products (furfural, hydroxymethylfurfural, and acetic acid), and lignin. Three conditions allowed reaching similar total sugar concentrations (~12 g/L): 160 °C for 90 min, 180 °C for 30 min, and 180 °C for 60 min. Among these, LHW performed at 160 °C for 90 min allowed the lowest concentration of degradation products (0.2, 0.01, and 1.4 g/L for furfural, hydroxymethylfurfural, and acetic acid, respectively) and lignin hydrolysis (2.2 g/L). These values indicate the potential use of the obtained sugars as a fermentation substrate while leaving the lignin in the solid phase for a following stage focused on its extraction and valorization.
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Danzi, Donatella, Ivana Marino, Isabella De Bari, Silvio Mastrolitti, Giacomo L. Petretto, Domenico Pignone, Michela Janni, Francesco Cellini et Tullio Venditti. « Assessment of Durum Wheat (Triticum durum Desf.) Genotypes Diversity for the Integrated Production of Bioethanol and Grains ». Energies 14, no 22 (18 novembre 2021) : 7735. http://dx.doi.org/10.3390/en14227735.
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Wheat straw is an abundant source of lignocellulosic biomass that is generally not utilized for biofuel production, nor for other uses. Recent EU renewable energy directive fosters bioethanol production through lignocellulosic sugars fermentation, but the cost of this process is an issue that often depends on biomass characteristics. Lignin is a class of three-dimensional polymers providing structural integrity of plant tissues. Its complex structure, together with hemicelluloses and uronic acids content, could affect the ability of hydrolyzing biomass to fermentable sugars. To get insights into this variation, a set of 10 durum wheat genotypes was analyzed to determine variation of straw digestibility to fermentable sugars. The results showed that the lignin content was the major factor determining the recalcitrance to enzymatic process. The analysis of Spearman’s correlation indicated that the sugar released after enzymatic hydrolysis had a negative connection with the lignin content, while it was positively correlated with the culm length. The possible role of other cell wall components, such as arabinose and uronic acids, was also discussed. This work aimed at analyzing the diversity of lignocellulosic digestibility to fermentable sugars of wheat straw in a small germplasm collection. Some of the selected genotypes were characterized by high sugars digestibility and high grain yield, characteristics that could make biorefining of wheat straw profitable.
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Ibarra, David, Raquel Martín-Sampedro, Laura Jiménez-López, Juan A. Martín, Manuel J. Díaz et María E. Eugenio. « Obtaining Fermentable Sugars from a Highly Productive Elm Clone Using Different Pretreatments ». Energies 14, no 9 (23 avril 2021) : 2415. http://dx.doi.org/10.3390/en14092415.
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The interest of supplying lignocellulosic materials for producing fermentable sugars has recently emerged in order to diminish the negative environmental effects of fossil fuels. In this study, the Ulmus minor clone Ademuz, characterized for its tolerance to Dutch elm disease and its rapid growth, was evaluated as a source of fermentable sugars. For that, different pretreatments, comprising autohydrolysis, dilute acid hydrolysis, acid catalyzed organosolv, and alkaline extraction, were evaluated at two levels of severity (pretreatment temperatures at 160 °C and 180 °C, except for alkaline extraction at 80 °C and 160 °C); and the resulting pretreated materials were enzymatically hydrolyzed for fermentable sugars production. The major extraction of lignin and hemicellulose was achieved during organosolv (48.9%, lignin; 77.9%, hemicellulose) and acid hydrolysis (39.2%, lignin; 95.0%, hemicellulose) at 180 °C, resulting in the major enzymatic digestibility (67.7%, organosolv; 53.5% acid hydrolysis). Contrarily, under the most favorable conditions for autohydrolysis (180 °C) and alkaline extraction (160 °C), lower extraction of lignin and hemicellulose was produced (4.8%, lignin; 67.2%, hemicellulose, autohydrolysis; 22.6%, lignin; 33.1%, hemicellulose, alkaline extraction), leading to lower enzymatic digestibility (32.1%, autohydrolysis; 39.2%, alkaline extraction). Taking into account the sugars produced during enzymatic hydrolysis of pretreated materials and the solubilized sugars from pretreatment liquors, the highest sugars (glucose and xylose) yield production (28.1%) per gram of biomass from U. minor clone Ademuz was achieved with acid catalyzed organosolv at 180 °C.
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Wyman, Charles E. « Cellulosic Ethanol : A Unique Sustainable Liquid Transportation Fuel ». MRS Bulletin 33, no 4 (avril 2008) : 381–83. http://dx.doi.org/10.1557/mrs2008.77.
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Although ethanol is now made from the sugars in the starch fraction of corn and other crops and from the sugar in sugarcane, a much greater impact for ethanol in terms of fuel use could be realized if the sugars from more recalcitrant cellulosic biomass could be converted to ethanol. Cellulosic biomass is the structural portion of plants and includes agricultural (e.g., corn stover, which is all of the above-ground portion of the corn plant, excluding the grain) and forestry (e.g., sawdust) residues, major fractions of municipal solid waste (e.g., waste paper and yard waste), and herbaceous (e.g., switchgrass) and woody (e.g., poplar) crops grown as energy resources. Although distinctive in outward appearance, these materials all comprise about 40–50% cellulose and 20–30% hemicellulose, with lesser amounts of lignin and other compounds such as sugars, oils, and minerals. Cellulose is a polymer of glucose sugar molecules that are physically linked together in a crystalline structure to provide structural support for plants. Hemicellulose is also made up of sugars covalently joined together in long chains, but it generally includes fve different sugars: arabinose, galactose, glucose, mannose, and xylose. In addition, hemicellulose is an amorphous, branched material. Lignin is a phenylpropene compound that can be viewed as a low-sulfur, immature coal.
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Svärd, Antonia, Olena Sevastyanova, Galina Dobele, Vilhemina Jurkjane et Elisabet Brännvall. « COST Action FP1105 : effect of raw materials and pulping conditions on the characteristics of dissolved kraft lignins ». Holzforschung 70, no 12 (1 décembre 2016) : 1105–14. http://dx.doi.org/10.1515/hf-2016-0057.
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Abstract The composition, molecular weight (MW), and chemical structure of technical lignins as byproducts of pulping influence their application in terms of physical and chemical properties, reactivity, and performance. It is important to know how the analytical data of technical lignins are influenced by the wood species and the parameters of pulping. The present study focuses on kraft pulping and how the wood species (eucalyptus, pine, and spruce) and variable cooking times influence the characteristics of dissolved lignins. The black liquor (BL) was recovered after three different cooking times and the precipitated lignin was characterized by total acid hydrolysis including the determination of the acid insoluble part (Klason lignin, KL) and the sugars in the hydrolysate, elemental analysis, 31P NMR spectroscopy, analytical pyrolysis (Py-GC/MS), gel permeation chromatography (GPC), thermogravimetry (TG), and differential scanning calorimetry (DSC). The results indicate that the phenolic OH content, MW and glass transition temperature increased with longer cooking times for the softwood (SW) lignins. These lignins had also a higher MW (Mw 5500–8000 g mol-1), than the eucalyptus lignin (Mw 2200–2400 g mol-1). Eucalyptus lignin had higher sulfur content compared to SW.
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Möller, A., K. Kaiser et W. Zech. « Lignin, carbohydrate, and amino sugar distribution and transformation in the tropical highland soils of northern Thailand under cabbage cultivation, Pinus reforestation, secondary forest, and primary forest ». Soil Research 40, no 6 (2002) : 977. http://dx.doi.org/10.1071/sr01030.
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Structure and transformation processes of soil organic matter (SOM) are extremely complex, but advancing our knowledge on SOM cycling is a prerequisite for a sustainable soil management. To get a better insight to this issue, we determined the vertical distribution of lignin, carbohydrates, and amino sugars in bulk soils and NaOH-extracts using wet chemical techniques. These results were compared with those obtained by solution 13C nuclear magnetic resonance (NMR) spectroscopy after alkaline extraction. Soil samples were taken under a primary forest, a secondary forest, a 20-year-old Pinus kesiya (Royle ex Gordon) reforestation established following 15 years of cultivation, and a cabbage cultivation site in northern Thailand. Significantly lower contents of organic C and N at the cabbage cultivation and reforestation sites indicated that the replacement of forests by arable land at the reforestation and cabbage cultivation sites about 30 years ago resulted in enhanced breakdown of SOM. This means that after 20 years of Pinus growth, reforestation did not lead to a significant build-up of organic matter in the mineral soil. With increasing soil depth the sites showed comparable decreases in soil organic matter, exhibiting a typical pattern of decomposition expressed by a higher degree of side chain oxidation, increasing carboxyl functionality, and a decrease of lignin-derived phenols and aromatic compounds. Microbial contribution to SOM was determined using the carbohydrate and amino sugar biomarker approach. The amino sugars were predominantly of fungal origin in the organic layer. In the mineral soil, bacterial amino sugars dominated and the relative contribution of amino sugars to SOM increased with depth. Comparison of results from wet chemical analyses and of liquid-state 13C NMR signatures requires that alkaline-extractable organic matter is representative for bulk soil organic matter. This seemed to apply to lignin-derived phenols and amino sugars but not to neutral sugars and uronic acids. Significant correlations were found for lignin-derived phenols with phenolic C (R = 0.74, P < 0.01) for the bulk forest site samples and amino sugars with O-alkyl C (R = 0.93, P < 0.001) for the mineral soil horizons, whereas the carbohydrate contents did not show any clear correlation. Therefore, we concluded that most of the phenolic C signal intensity might be attributed to lignin, and the enrichment of O-alkyl C with depth may be a result of bacterial resynthesis with a significant contribution of amino sugars.
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Vishtal, Alexey, et Andrzej Kraslawski. « Challenges in industrial applications of technical lignins ». BioResources 6, no 3 (7 juin 2011) : 3547–68. http://dx.doi.org/10.15376/biores.6.3.3547-3568.
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The primary aim of modern biorefineries is the efficient conversion of lignocellulosic materials into valuable products. Sugars and oils can be converted into valuable chemicals, but processing of lignin is still a challenge. A vast amount of lignin is incinerated to produce process steam and energy, and only a very small part is used for the production of value-added products. Technical lignins are isolated as by-streams in lignocellulosic refineries, e.g., as kraft, soda, organosolv, and hydrolysis lignins, as well as lignosulphonates. They have a modified structure and contain impurities that are dependent on the processing method. The structure and the composition of technical lignins restrict their subsequent applications. This paper reviews limiting factors in utilization of technical lignins. Four major classes of problems are identified, and approaches to overcoming these problems are suggested.
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Vishtal, Alexey, et Andrzej Kraslawski. « Challenges in industrial applications of technical lignins ». BioResources 6, no 3 (7 juin 2011) : 3547–68. http://dx.doi.org/10.15376/biores.6.3.vishtal.
Texte intégralRésumé :
The primary aim of modern biorefineries is the efficient conversion of lignocellulosic materials into valuable products. Sugars and oils can be converted into valuable chemicals, but processing of lignin is still a challenge. A vast amount of lignin is incinerated to produce process steam and energy, and only a very small part is used for the production of value-added products. Technical lignins are isolated as by-streams in lignocellulosic refineries, e.g., as kraft, soda, organosolv, and hydrolysis lignins, as well as lignosulphonates. They have a modified structure and contain impurities that are dependent on the processing method. The structure and the composition of technical lignins restrict their subsequent applications. This paper reviews limiting factors in utilization of technical lignins. Four major classes of problems are identified, and approaches to overcoming these problems are suggested.
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Ivetic, Darjana, Vesna Vasic, Marina Sciban et Mirjana Antov. « Analysis of pretreatments of sugar beet shreds for bioethanol production in respect of cellulose hydrolysis and waste flows ». Acta Periodica Technologica, no 42 (2011) : 223–30. http://dx.doi.org/10.2298/apt1142223i.
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This paper analyzes some chemical pretreatments of sugar beet shreds concerning generated waste flows and yield of reducing sugars obtained by enzymatic hydrolysis of pretreated material. Waste flows produced in pretreatments of sugar beet shreds originated from pectin and lignin removal from raw material. Suitability of substrates prepared in single and two-step pretreatment procedure for enzymatic hydrolysis was determined based on the yield of reducing sugars released by cellulase action on them, while different possibilities of processing of wastewaters were discussed based on the characteristic of waste flows.
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Liu, Gang, Hai Qiang Shi, Qing Wei Ping, Jian Zhang, Na Li et Mei Hong Niu. « Flocculation Process of PEO for Lignin Removal from Pre-Hydrolysis Liquor of Mixed Hardwood ». Advanced Materials Research 726-731 (août 2013) : 1859–62. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1859.
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To isolate lignin of PHL, PEO with various molecular weights (MW) s were added to PHL under different process conditions, and the turbidity and size of complexes formed in the PHL, as well as the lignin, hemicelluloses (sugar) and chemical oxygen demand (COD) of PHL were assessed after PEO treatments. Alternatively, poly aluminum chloride (PAC) (200 mg/l) and PEO (8 MDa MW) (200 mg/l) were employed in a dual polymer system to extract the lignin of PHL. In this work, the maximum removals of 46% lignin, 18.8% sugars, and 32% COD were obtained under the conditions of 400 mg/g PEO (with a MW of 8 MDa) at pH 2 and room temperature in a singular PEO polymer system.
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Zhang, Xinghua, Zhengqiu Yuan, Tiejun Wang, Qi Zhang et Longlong Ma. « Effect of the temperature on the dissolution of corn straw in ethanol solution ». RSC Advances 6, no 104 (2016) : 102306–14. http://dx.doi.org/10.1039/c6ra22456c.
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Ben’ko, Elena Mikhailovna, et Valeriy Vasil'yevich Lunin. « OZONE PRETREATMENT OF LIGNOCELLULOSIC MATERIALS : THE EFFECT OF OZONE CONSUMPTION ON REACTIVITY IN ENZYMATIC HYDROLYSIS INTO SUGAR ». chemistry of plant raw material, no 4 (27 décembre 2019) : 305–14. http://dx.doi.org/10.14258/jcprm.2019045323.
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Ozonolysis, as a lignocellulosic biomass pretreatment for sugars and bioethanol production is becoming widespread in recent years owing to its efficiency and environmental safety. Ozone reacts preferably with lignin than carbohydrates, leading to biomass delignification, and so the sugar release by enzymatic hydrolysis. Sugars yield depends on ozone pretreatment parameters and additional studies are necessary to optimize the process to achieve high yields with economic feasibility.
In this work some general patterns of ozone pretreatment are established, using the samples of plant biomass of various types (straw, soft and hardwood). It is shown that the reactivity of vegetable substrates pretreated with ozone is determined by the amount of ozone consumed and practically does not depend on the conditions under which this value of ozone consumption was achieved. The optimal value of ozone consumption, which allows to obtain the maximum yield of sugars in the enzymatic reaction, is 2–3 eq. O3/C9PPU (in terms of phenyl-propane structural unit of lignin, contained in the raw material) or 10–15 wt.%. Intermediate ozonation products do not exhibit inhibitory properties at such ozone consumption.
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Charisteidis, Ioannis, Polykarpos Lazaridis, Apostolos Fotopoulos, Eleni Pachatouridou, Leonidas Matsakas, Ulrika Rova, Paul Christakopoulos et Konstantinos Triantafyllidis. « Catalytic Fast Pyrolysis of Lignin Isolated by Hybrid Organosolv—Steam Explosion Pretreatment of Hardwood and Softwood Biomass for the Production of Phenolics and Aromatics ». Catalysts 9, no 11 (8 novembre 2019) : 935. http://dx.doi.org/10.3390/catal9110935.
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Lignin, one of the three main structural biopolymers of lignocellulosic biomass, is the most abundant natural source of aromatics with a great valorization potential towards the production of fuels, chemicals, and polymers. Although kraft lignin and lignosulphonates, as byproducts of the pulp/paper industry, are available in vast amounts, other types of lignins, such as the organosolv or the hydrolysis lignin, are becoming increasingly important, as they are side-streams of new biorefinery processes aiming at the (bio)catalytic valorization of biomass sugars. Within this context, in this work, we studied the thermal (non-catalytic) and catalytic fast pyrolysis of softwood (spruce) and hardwood (birch) lignins, isolated by a hybrid organosolv–steam explosion biomass pretreatment method in order to investigate the effect of lignin origin/composition on product yields and lignin bio-oil composition. The catalysts studied were conventional microporous ZSM-5 (Zeolite Socony Mobil–5) zeolites and hierarchical ZSM-5 zeolites with intracrystal mesopores (i.e., 9 and 45 nm) or nano-sized ZSM-5 with a high external surface. All ZSM-5 zeolites were active in converting the initially produced via thermal pyrolysis alkoxy-phenols (i.e., of guaiacyl and syringyl/guaiacyl type for spruce and birch lignin, respectively) towards BTX (benzene, toluene, xylene) aromatics, alkyl-phenols and polycyclic aromatic hydrocarbons (PAHs, mainly naphthalenes), with the mesoporous ZSM-5 exhibiting higher dealkoxylation reactivity and being significantly more selective towards mono-aromatics compared to the conventional ZSM-5, for both spruce and birch lignin.
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Dang, Binh T. T., Harald Brelid et Hans Theliander. « Carbohydrate content of black liquor and precipitated lignin at different ionic strengths in flow-through kraft cooking ». Holzforschung 72, no 7 (26 juillet 2018) : 539–47. http://dx.doi.org/10.1515/hf-2017-0146.
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AbstractThe influence of sodium ion concentration [Na+] on the dissolution of carbohydrates in black liquor (BL) during flow-through kraft cooking of Scots pine wood meal (Pinus sylvestris) was studied. Fractions of BL were collected at different times and the carbohydrate content of the various fractions was analysed. Lignin was precipitated from the BL by lowering the pH, and the carbohydrate content of the precipitated lignins (Lprec) was also examined. The molecular weight distribution (MWD) of the Lprecsamples was analysed. Xylose (Xyl) was found to be the most predominant sugar in BL aside from arabinose (Ara) and galactose (Gal), while the amounts of these sugars decreased with increasing levels of [Na+] in the cooking liquor. The minor amounts of mannose (Man) found in BL was not influenced by the [Na+]. The effects of NaCl and Na2CO3on the carbohydrate dissolution were similar, but slightly lower concentrations of Ara and Xyl were found in the case of NaCl application. All of the Lprecsamples contained some carbohydrate residues, the contents of which increased with increasing cooking time and decreased with higher [Na+]. It can be concluded that arabinoglucuronoxylan (AGX) along with arabinogalactans (AG) and arabinan, are covalently linked to lignin. The glucose (Glc) residue detected in Lprecmay originate from 1,3-β-glucan linked to lignin.
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Alvarez-Barreto, Jose F., Fernando Larrea, Maria C. Pinos C, Jose Benalcázar, Daniela Oña, Daniela A. Viteri, Marco Leon et Daniela Almeida-Streitwieser D. « Chemical Pretreatments on Residual Cocoa Pod Shell Biomass for Bioethanol Production ». Bionatura 6, no 1 (15 février 2021) : 1490–500. http://dx.doi.org/10.21931/rb/2020.06.01.9.
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Cocoa pod shell is an essential agricultural residue in Ecuador, and this study addressed its potential valorization for bioethanol production. For this, three types of pretreatments, acid, alkaline, and autohydrolysis, were applied to pod shells from two different cocoa types, national and CCN-51. to remove the lignin. Untreated and treated biomasses were characterized by composition, thermal stability, Fourier transformed infrared spectroscopy (FITR), and scanning electron microscopy (SEM). The treated biomass was then enzymatically hydrolyzed with cellulase. Reducing sugars were quantified after pretreatments and enzymatic hydrolysis, and the pretreatment liquors and the enzymatic hydrolysates were subjected to alcoholic fermentation with Saccharomyces cerevisiae. There were substantial differences in composition between both biomasses, particularly in lignin content, with national cocoa having the lowest values. All pretreatment conditions had significant effects on biomass composition, structure, and thermal properties. After alkaline pretreatment, the biomass presented the highest cellulose and lowest lignin contents, resulting in the highest reducing sugar concentration in the pretreatment liquor. The highest lignin content was found after the acid pretreatment, which resulted in low, reducing sugar concentrations. Autohydrolysis produced similar results as the acid pretreatment; however, it resulted in the highest sugar concentration after enzymatic hydrolysis, while the acid-treated sample had negligible levels. After fermentation, there were no differences in productivity among the pretreatment liquors, but autohydrolysis had the largest ethanol yield. In the hydrolysates, it was also autohydrolysis that resulted in higher productivity and yield. Thus, there is an indication of the formation of inhibitors, both enzymatic activity and ethanol production, in the acid and alkaline pretreatments, and this should be tackled in future research. Nonetheless, given the crucial changes observed in biomass, we believe that cocoa pod shell pretreatment has potential for the generation of reducing sugars that could be further used in different bioprocesses, nor only bioethanol production.
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Ben’ko, Elena M., Dmitriy G. Chukhchin et Valeriy V. Lunin. « Changes in wheat straw cell walls during ozone pretreatment ». Holzforschung 74, no 12 (18 novembre 2020) : 1157–67. http://dx.doi.org/10.1515/hf-2019-0168.
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AbstractTreatment of plant biomass with ozone is a promising delignification method. It was shown that lignin removal from the cell wall during ozonation was limited by topochemical reactions and toke place in the secondary rather in the primary cell wall. The separation of cellulose microfibrils, the loss of cell wall stiffness and complete removal of intercellular substance during the delignification process were visualized by SEM. The dependence of the average diameter of the cellulose microfibril aggregates in the cell wall of ozonized straw on ozone consumption was studied. Lignin removal caused an increase of size of cellulose microfibrils aggregates. It was demonstrated that there was an optimal degree of delignification, at which cellulose became more accessible to enzymes in the subsequent bioconversion processes. The data on the ozone consumption, residual lignin content, and sugars yield in the enzymatic hydrolysis of ozonized wheat straw were obtained. It was also found that the optimum delignification degree for sugars yield was ≈10% of residual lignin content and optimum ozone consumption was 2 mol·О3/mol C9PPU (phenylpropane structural unit) of lignin in raw straw.
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De bruyn, M., J. Fan, V. L. Budarin, D. J. Macquarrie, L. D. Gomez, R. Simister, T. J. Farmer, W. D. Raverty, S. J. McQueen-Mason et J. H. Clark. « A new perspective in bio-refining : levoglucosenone and cleaner lignin from waste biorefinery hydrolysis lignin by selective conversion of residual saccharides ». Energy & ; Environmental Science 9, no 8 (2016) : 2571–74. http://dx.doi.org/10.1039/c6ee01352j.
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Kasangana, Pierre Betu, Sagar Bhatta et Tatjana Stevanovic. « Effect of Pre-Extraction on Composition of Residual Liquor Obtained from Catalytic Organosolv Pulping of Sugar Maple Bark ». Sustainable Chemistry 1, no 1 (19 mai 2020) : 23–32. http://dx.doi.org/10.3390/suschem1010002.
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Background: We have determined previously that the water extract of sugar maple bark contained an important quantity of a complex sugar. In this study, we investigated the organosolv pulping of pre-extracted bark to follow the acid conversion of sugars into major products, furfural and 5-hydroxymethyl-2-furfural (HMF), while comparing the structures of organosolv lignins. Methods: The bark particles were pre-extracted with an ethanol–water mixture or water only. The extractives-free barks were then converted into cellulosic pulp and lignin by a patented organosolv process. The composition of residual liquor was determined by using HPLC-UV. Results: The pre-extraction with water was more efficient for complex sugars recovery than with the ethanol–water system. HMF was determined to be more abundant in residual liquor than furfural after ethanol–water pre-extraction while their quantities were comparable in the residual liquor after water pre-extraction. The higher yield of HMF from ethanol–water pre-extracted bark (1.18%) than from water pre-extracted (0.69%) could be related to the efficiency of complex sugar removal during the pre-extraction step. Conclusions: The pre-extraction before pulping affected, at least in part, the composition of residual liquor in terms of HMF production. These results demonstrate how the bark can be converted into valuable products and intermediates for organic synthesis.
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J. NICHOLSON, DAVID, GUSTAVO V. DUARTE, ERICKA F. ALVES, DAVID J. KIEMLE, AARON T. LEAVITT et RAYMOND C. FRANCIS. « Quantification of lignin-carbohydrate complexes in hardwood pulps, Part 2 : Effects of bleaching chemicals ». October 2015 14, no 10 (1 novembre 2015) : 663–70. http://dx.doi.org/10.32964/tj14.10.663.
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High kappa number kraft and soda-anthraquinone (soda-AQ or SAQ) pulps from sugar maple (Acer saccharum) were investigated to see how the lignin-carbohydrate complexes (LCC) they contained affected lignin removal by oxygen, chlorine dioxide, and hydrogen peroxide. The chlorine dioxide and hydrogen peroxide doses were higher than normal because both pulps had unbleached kappa numbers in the range of 61-62. Only oxygen delignification was investigated with the SAQ pulp. The research focused on the strong lignin-carbohydrate (L-C) linkages only. The pulp carbohydrates were enzymatically degraded and solubilized, thus leaving an enzymatic lignin (EL) residue. The highest concentration of bound sugars (glucan, xylan, arabinan, and galactan) on any of the ELs was <2.1 wt%. Chlorine dioxide (D stage) was investigated at end pHs of 2.1, 2.9, and 4.0, followed by extraction with dilute sodium hydroxide. Lignin oligomers containing bound glucan and arabinan were unreactive and accumulated in the fibers. When oxygen was used to delignify kraft and SAQ pulps by ~50%, only ~10% of the lignin bound arabinan was solubilized. Galacto-lignin complexes were somewhat reactive to oxygen and hydrogen peroxide under alkaline conditions, but less reactive in the D stages. Consistent with literature data, xylo-lignin complexes were reactive toward oxygen and toward the other two oxidants. They do not appear to be major impediments in the bleaching process.
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Parveen, Heena, Lakshmi Tewari, Diwas Pradhan et Parul Chaudhary. « Comparative study of diverse pretreatment approaches to degrade lignin from Bambusa balcooa ». BioResources 17, no 4 (4 août 2022) : 5578–99. http://dx.doi.org/10.15376/biores.17.4.5578-5599.
Texte intégralRésumé :
Bamboo biomass is a potential source of monomeric sugars containing a high cellulose content with a low amount of lignin. However, for efficient hydrolysis, an effective biomass pretreatment technique is required to minimize the lignin content and other barrier components. In the present study, bamboo biomass was treated with different physical, chemical, biological, and combined treatments to reduce the lignin content. Among all the pretreatments, the maximum lignin removal amount (14.5%) was obtained with the combined chemical and biological treatment under 2% NaOH + 1% H2O2 + WDP2 fungal culture (5 plugs) conditions. In addition, the ligninolytic fungus and NaOH pretreatment was primarily effective in removing lignins, whereas the H2O2 pretreatment efficiently minimized cellulose crystallinity. Scanning electron microscopy and Fourier-transform infrared spectroscopy was utilized to analyze the structural changes of the raw and treated biomass. The structural analysis indicated that all the treatments caused disruption in the biomass structure and reduced the compactness of the biomass, which facilitated the biomass conversion during the hydrolysis process. The findings of the present study indicated effective pretreatment methods in overcoming the recalcitrancy of potential lignocellulosic biomass for maximum hydrolysis.
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Gupta, Murlidhar, Benjamin King, Fernando Preto et Andrew McFarlan. « A comparative analysis of heat recovery and product stabilization in fluid-bed and ablative pyrolysis systems ». E3S Web of Conferences 61 (2018) : 00017. http://dx.doi.org/10.1051/e3sconf/20186100017.
Texte intégralRésumé :
Nearly all existing commercial pyrolysis technologies employ single-step rapid condensation of vapours from 500 oC to 50 oC using sprays of cold bio-oil or liquid hydrocarbon as a quench fluid. This approach produces raw bio-oil, a non-homogenous mixture of hundreds of oxygenated organic compounds including organic acids and water. Single-step quench also results in loss of high quality heat to the ambient. In this work, a novel 3-stage fractional condensation approach has been proposed. The intent is to produce targeted stable products for value added applications as well to enhance the overall efficiency of pyrolysis processes. The first phase of this research involved modelling and simulation of staged condensation of pyrolysis vapours using Pro/2 process software. A comprehensive pyrolysis model with 13 representative compounds was developed and validated. The Pro/2 model is able to simulate complex condensation of lignin and sugar fractions at high temperatures. Multiple cases involving staged condensation in ablative and fluid bed pyrolysis systems were investigated. In each case, there was a trade-off between high-quality heat recovery and early separation of lignin and sugars from organic acids. Results demonstrated that dew point depression adds additional complexity and limits heat recovery. However, judicious selection of condenser temperatures offers opportunity for early isolation of sugars and lignin from acids, thereby improving product stability.
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Oriez, Vincent, Jérôme Peydecastaing et Pierre-Yves Pontalier. « Lignocellulosic Biomass Fractionation by Mineral Acids and Resulting Extract Purification Processes : Conditions, Yields, and Purities ». Molecules 24, no 23 (23 novembre 2019) : 4273. http://dx.doi.org/10.3390/molecules24234273.
Texte intégralRésumé :
Fractionation of lignocellulose is a fundamental step in the valorization of cellulose, hemicelluloses, and lignin to produce various sustainable fuels and chemicals. Mineral acid fractionation is one of the most applied process and leads to the solubilization and hydrolysis of cellulose and hemicelluloses, whereas most of the lignin remains insoluble and can be separated from the extract. The obtained monomeric sugars in the acid extract are in solution with salts, sugar degradation products, and phenolic molecules. Downstream processing is required to purify the sugars and further valorize them into fuels or chemicals with the use of chemical or biochemical reactions. This purification step also allows the recycling of the mineral acid and the valorization of the sugar degradation products and the co-extracted phenolic molecules, adding value to the whole biorefinery scheme. Many purification techniques have been studied, providing several options in terms of yields, purities, and cost of the process. This review presents the conditions used for the mineral acid fractionation step and a wide variety of purification techniques applied on the obtained hydrolysate, with a focus on the associated yields and purities. Values from the literature are expressed in a standard way in order to simplify comparison between the different processes.
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Chen, Yuanhang, Zhenyun Yan, Long Liang, Miao Ran, Ting Wu, Baobin Wang, Xiuxiu Zou, Mengke Zhao, Guigan Fang et Kuizhong Shen. « Comparative Evaluation of Organic Acid Pretreatment of Eucalyptus for Kraft Dissolving Pulp Production ». Materials 13, no 2 (12 janvier 2020) : 361. http://dx.doi.org/10.3390/ma13020361.
Texte intégralRésumé :
Pretreatment is an essential process for the extensive utilization of lignocellulose materials. The effect of four common organic acid pretreatments for Kraft dissolving pulp production was comparatively investigated. It was found that under acidic conditions, hemicellulose can be effectively removed and more reducing sugars can be recovered. During acetic acid pretreatment, lignin that was dissolved in acetic acid could form a lignin-related film which would alleviate cellulose hydrolysis, while other organic acids caused severe cellulose degradation. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) were used to characterize the pretreated chips in the process. Lignin droplets were attached to the surface of the treated wood chips according to the SEM results. The FTIR spectrum showed that the lignin peak signal becomes stronger, and the hemicellulose peak signal becomes weaker with acid pretreatment. The XRD spectrum demonstrated that the crystallinity index of the wood chips increased. The acetic acid pretreatment process-assisted Kraft process achieved higher yield (31.66%) and higher α-cellulose (98.28%) than any other organic acid pretreatment. Furthermore, extensive utilization of biomass was evaluated with the acetic acid pretreatment-assisted Kraft process. 43.8% polysaccharide (12.14% reducing sugar and 31.66% dissolving pulp) and 22.24% lignin (0.29% acetic acid lignin and 21.95% sulfate lignin) were recovered during the process. Biomass utilization could reach 66.04%. Acetic acid pretreatment is a promising process for extensive biomass utilization.
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Amezcua-Allieri, Myriam A., Teresa Sánchez Durán et Jorge Aburto. « Study of Chemical and Enzymatic Hydrolysis of Cellulosic Material to Obtain Fermentable Sugars ». Journal of Chemistry 2017 (2017) : 1–9. http://dx.doi.org/10.1155/2017/5680105.
Texte intégralRésumé :
The objective of this study was to evaluate the chemical and enzymatic hydrolysis using a factorial experimental design (23) in order to obtain fermentable sugars from cellulose-based material (CBM) usually used as pet litter. In assessing chemical hydrolysis, we studied the effect of temperature, in addition to H2SO4 concentration and reaction time, on the production of total sugars, reducing sugars, soluble lignin, carbohydrate profile, furfural (F), and hydroxymethyl furfural (HMF). We performed a response surface analysis and found that, at 100°C, 1% acid concentration, and 60 min reaction time, the yields of 0.0033 g reducing sugar/g biomass and 0.0852 g total sugars/g biomass were obtained. Under the above conditions, F is not generated, while HMF is generated in such a concentration that does not inhibit fermentation. We pretreated the CBM with H2SO4, NaOH, CaO, or ozonolysis, in order to evaluate the effectiveness of the enzymatic hydrolysis from the pretreated biomass, using an enzymatic cocktail. Results showed that CBM with acid was susceptible to enzymatic attack, obtaining a concentration of 0.1570 g reducing sugars/g biomass and 0.3798 g total sugars/g biomass. We concluded that acid pretreatment was the best to obtain fermentable sugars from CBM.
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Li, Lingci, Peng Ye, Mengyu Chen, Shangyuan Tang, Ying Luo, Yifan Gao, Qiong Yan et Xiyu Cheng. « A Two-Step Ferric Chloride and Dilute Alkaline Pretreatment for Enhancing Enzymatic Hydrolysis and Fermentable Sugar Recovery from Miscanthus sinensis ». Molecules 25, no 8 (16 avril 2020) : 1843. http://dx.doi.org/10.3390/molecules25081843.
Texte intégralRésumé :
A two-step process was proposed to enhance enzymatic hydrolysis of Miscanthus sinensis based on a comparative study of acid/alkaline pretreatments. Ferric chloride pretreatment (FP) effectively removed hemicellulose and recovered soluble sugars, but the enzymatic hydrolysis was not efficient. Dilute alkaline pretreatment (ALP) resulted in much better delignification and stronger morphological changes of the sample, making it more accessible to enzymes. While ALP obtained the highest sugar yield during enzymatic hydrolysis, the soluble sugar recovery from the pretreatment stage was still limited. Furthermore, a two-step ferric chloride and dilute alkaline pretreatment (F-ALP) has been successfully developed by effectively recovering soluble sugars in the first FP step and further removing lignin of the FP sample in the second ALP step to improve its enzymatic hydrolysis. As a result, the two-step process yielded the highest total sugar recovery (418.8 mg/g raw stalk) through the whole process.
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Zhang, Xihui, Guang Yu, Xiaoyan Feng, Zhenqiu Li, Bin Li et Qiu Cui. « Ammonia-ethanol-water pretreatment of wheat straw for facilitating enzymatic saccharification integrated with the preparation of submicron lignin spheres ». BioResources 15, no 3 (14 mai 2020) : 5087–109. http://dx.doi.org/10.15376/biores.15.3.5087-5109.
Texte intégralRésumé :
Ammonia-ethanol-water (AEW) pretreatment was adopted to treat wheat straw for ameliorating saccharification with the integrated preparation of submicron lignin spheres (SLS). Results showed that AEW pretreatment could remove 77% of lignin and 90% of extractives, thus increasing specific surface area and porosity of the substrate and finally enhancing the release of fermentable sugars in saccharification. Under the optimal pretreatment conditions (170 °C for 2 h, ethanol concentration 55% (v/v), ammonia concentration 7.5 wt%), the final total sugar yield reached 81.7% after pretreatment and saccharification, which was 2.25 times higher compared to the conventional ethanol organosolv pretreatment. Moreover, washing could be excluded for AEW-pretreated wheat straw before saccharification, and both ethanol and ammonia could be readily recovered and reused, making the AEW pretreatment clean and sustainable. In addition, SLS with hollow structure and average diameter of 161.2 ± 53.6 nm were fabricated using the fractionated lignin, which could offset the overall cost of AEW pretreatment.
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Llano, Tamara, Noelia García-Quevedo, Natalia Quijorna, Javier R. Viguri et Alberto Coz. « Evolution of Lignocellulosic Macrocomponents in the Wastewater Streams of a Sulfite Pulp Mill : A Preliminary Biorefining Approach ». Journal of Chemistry 2015 (2015) : 1–10. http://dx.doi.org/10.1155/2015/102534.
Texte intégralRésumé :
The evolution of lignin, five- and six-carbon sugars, and other decomposition products derived from hemicelluloses and cellulose was monitored in a sulfite pulp mill. The wastewater streams were characterized and the mass balances throughout digestion and total chlorine free bleaching stages were determined. Summative analysis in conjunction with pulp parameters highlights some process guidelines and valorization alternatives towards the transformation of the traditional factory into a lignocellulosic biorefinery. The results showed a good separation of cellulose (99.64%) during wood digestion, with 87.23% of hemicellulose and 98.47% lignin dissolved into the waste streams. The following steps should be carried out to increase the sugar content into the waste streams: (i) optimization of the digestion conditions increasing hemicellulose depolymerization; (ii) improvement of the ozonation and peroxide bleaching stages, avoiding deconstruction of the cellulose chains but maintaining impurity removal; (iii) fractionation of the waste water streams, separating sugars from the rest of toxic inhibitors for 2nd generation biofuel production. A total of 0.173 L of second-generation ethanol can be obtained in the spent liquor per gram of dry wood. The proposed methodology can be usefully incorporated into other related industrial sectors.
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Sato, Abas, Arief Widjaja, Khozin Asror et Ayu Rahma Emilia. « Influence of alkaline addition on the composition and yield on the hydrothermal treatment of rice straw ». Malaysian Journal of Fundamental and Applied Sciences 15, no 4 (25 août 2019) : 537–42. http://dx.doi.org/10.11113/mjfas.v15n4.1077.
Texte intégralRésumé :
Agricultural waste is abundantly available in Indonesia, including rice straw. The largest components of rice straw are cellulose, hemicellulose, and lignin, making this material good enough as raw material for production of biogas, bioethanol, and other renewable fuels. The bonds in the cellulose and lignin in rice straw are strong and difficult to degrade which consequently will block the microorganisms to degrade them. In this study, a hydrothermal treatment was performed with the addition of NaOH. The purpose of this study was to investigate the effect of alkaline hydrothermal treatment on rice straw delignification, cellulose and hemicellulose solubility, the formation of reducing and furfural sugars, as well as the degrees of cellulose crystallinity. The variables used were NaOH concentration of 3%, 5%, and 7% (w/w total solid) and temperature were 100 ℃, 120 ℃, and 140 ℃. Treatment was performed using an autoclave with water and rice straw ratio of 8:1 with heating time for 2 hours. The results of this study showed that hydrothermal and NaOH treatment can increase rice straw organic degradation as indicated by increasing delignification of rice straw and increased levels of watersoluble sugars. The higher the temperature and the NaOH concentration, the more lignin and soluble hemicellulose content. Meanwhile, the reducing sugar increases with increasing temperature and NaOH concentration. Thermal decomposition rate has also occurred at lower temperature. It was found that the highest organic rice straw degradation occurs at higher temperature and NaOH concentration.
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Saulawa, Zeenat Ibrahim, Lawal Nura, Muntari Bala et Abdullahi A. Iman. « PRETREATMENT OF MILLET HUSK USING ALKALINE HYDROGEN PEROXIDE TO ENHANCE ENZYMATIC HYDROLYSIS FOR REDUCING SUGAR PRODUCTION ». FUDMA JOURNAL OF SCIENCES 5, no 2 (6 juillet 2021) : 289–94. http://dx.doi.org/10.33003/fjs-2021-0502-617.
Texte intégralRésumé :
The effectiveness of alkaline hydrogen peroxide as a suitable choice of pretreatment for the conversion of millet husk to reducing sugars using cellulase enzyme for hydrolysis and subsequent ethanol production was determined. The effects of three variables on reducing sugar production from millet husk were determined using one factor at a time (OFAT) method namely; peroxide concentration, pretreatment time and pretreatment temperature. From the results, it was observed that a significant (P<0.05) amount of reducing sugars were lost during pretreatment of millet husk. The untreated group which was only physically pretreated (milled) however yielded a significantly higher (P<0.05) reducing sugar concentration of 10.67mg/ml after enzymatic hydrolysis while the highest reducing sugar concentration of 4.82mg/ml was obtained using 0.375%v/v peroxide concentration for 60minutes at 250C. Therefore, pretreatment of biomass with alkaline hydrogen peroxide may be more suitable for feedstock with high lignin contents than millet husk.
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Santana, Marcos Antonio Eduardo, et Esmeralda Yoshico Arakaki Okino. « Chemical composition of 36 Brazilian Amazon forest wood species ». Holzforschung 61, no 5 (1 août 2007) : 469–77. http://dx.doi.org/10.1515/hf.2007.084.
Texte intégralRésumé :
Abstract Woods of 36 tree species from the Brazilian Amazon forest have been extracted and analyzed by means of total hydrolysis. For each species, three trees were analyzed in duplicate. The sugars and other byproducts of hydrolysis were analyzed by HPLC. Uronic anhydrides and acid-soluble lignin were determined by colorimetric methods. Acid-insoluble lignin, ash, and extractive contents were analyzed gravimetrically. Each analysis was performed several times and the data were evaluated statistically. The average percentages for ash and extractives are presented. Quantitative data for sugars obtained by HPLC were recalculated for glucan, galactan, arabinan, and mannan contents. These data are presented together with quantitative data for acetyl groups, 5-hydroxymethyl-2-furfuraldehyde, levulinic acid, uronic anhydride, acid-soluble and -insoluble lignin as summative analysis data based on an ash- and extractive-free basis, where, in an ideal case, the data should sum up to 100%. The summative results obtained varied from 96.0% to 99.6%, which is very satisfactory.
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Nakamura, Sachiko, et Norio Kurosawa. « Decomposition of Rice Chaff Using a Cocultivation System of Thermobifida fusca and Ureibacillus thermosphaericus ». Proceedings 66, no 1 (12 janvier 2021) : 31. http://dx.doi.org/10.3390/proceedings2020066031.
Texte intégralRésumé :
Lignocellulosic biomass comprises cellulose, hemicellulose, and lignin and is a potential source of fuels and chemicals. Although this complex biomass is persistent, it can be cooperatively decomposed by a microbial consortium in nature. In this study, a coculture of the moderately thermophilic bacteria Thermobifida fusca and Ureibacillus thermosphaericus was used for biodegradation of rice chaff. The bacterial strains were incubated in modified Brock’s basal salt medium (pH 8.0) supplemented with yeast extract and rice chaff at 50 °C for 7 days. The concentration of reducing sugars and the enzymatic activities of laccase, lignin peroxidase, cellulase, and xylanase in the supernatant of the culture medium were measured every day. The concentrations of reducing sugars in solo cultures of T. fusca and U. thermosphaericus and a mixed culture of the two strains after 7 days of incubation were 0.047, 0.040, and 0.195 mg/mL, respectively, indicating that the decomposition of rice chaff was enhanced in the coculture. Based on the results, it is thought that the lignin surrounding the cellulose was decomposed by laccase and lignin peroxidase secreted from U. thermosphaericus, resulting in cellulose and hemicellulose in the rice chaff being easily decomposed by enzymes from T. fusca.
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Smit, Arjan, et Wouter Huijgen. « Effective fractionation of lignocellulose in herbaceous biomass and hardwood using a mild acetone organosolv process ». Green Chemistry 19, no 22 (2017) : 5505–14. http://dx.doi.org/10.1039/c7gc02379k.
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Mazar, Adil, Naceur Jemaa, Waleed Wafa Al Dajani, Mariya Marinova et Michel Perrier. « Optimization of Lignin Recovery from the Pre-Hydrolysate of Kraft-Based Dissolving Pulp Production Processes ». Applied Sciences 11, no 1 (5 janvier 2021) : 454. http://dx.doi.org/10.3390/app11010454.
Texte intégralRésumé :
A pre-hydrolysate is an aqueous stream obtained during the production of hardwood kraft dissolving pulp. It is rich in sugars and contains dissolved organic matters. The purpose of this study is to investigate the optimization of lignin recovery from wood pre-hydrolysates and to characterize the extracted lignin. The optimal conditions for lignin extraction have been determined to be (a) a filtration temperature of 40 °C, (b) a sulfuric acid concentration of 8.5 kg·m−3, and (c) a coagulation time of 180 min. Using these conditions, high filtration rates have been obtained and the extracted lignin has a low content of impurities (8.3%), a low molecular weight (1270 Da), and a very low polydispersity (Mw/Mn = 1.22). Compared to kraft lignin, the pre-hydrolysate lignin has a much lower molecular weight and could be a potential candidate for niche applications. A high lignin recovery rate is possible (52% of the total lignin content in the pre-hydrolysate).
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Wang, Kui, Xinfeng Xie, Zhan Si, Jianchun Jiang et Jingxin Wang. « Microwave Assisted Hydrolysis of Holocellulose Catalyzed with Sulfonated Char Derived from Lignin-Rich Residue ». Advances in Materials Science and Engineering 2015 (2015) : 1–5. http://dx.doi.org/10.1155/2015/106137.
Texte intégralRésumé :
A microwave assisted green process has been developed for production of sugars through liquefying holocellulose catalyzed with sulfonated char derived from the lignin-rich residue produced during pretreatment of lignocellulose. Various reaction parameters including the hydrolysis temperature, hydrolysis time, catalyst content, and the ratio of water to feedstock were evaluated. The maximum sugars yield of 82.6% (based on the dry mass of holocellulose) was obtained under the optimum reaction conditions. The sulfonated char showed superior catalytic performance to that of dilute sulfuric acid in converting holocellulose into sugars under microwave irradiation.
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Cantero, Danilo A., Celia Martínez, M. D. Bermejo et M. J. Cocero. « Simultaneous and selective recovery of cellulose and hemicellulose fractions from wheat bran by supercritical water hydrolysis ». Green Chemistry 17, no 1 (2015) : 610–18. http://dx.doi.org/10.1039/c4gc01359j.
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Kouris, Panos D., Xiaoming Huang, Xianhong Ouyang, Dannie J. G. P. van Osch, Geert J. W. Cremers, Michael D. Boot et Emiel J. M. Hensen. « The Impact of Biomass and Acid Loading on Methanolysis during Two-Step Lignin-First Processing of Birchwood ». Catalysts 11, no 6 (19 juin 2021) : 750. http://dx.doi.org/10.3390/catal11060750.
Texte intégralRésumé :
We optimized the solvolysis step in methanol for two-step lignin-first upgrading of woody biomass. Birchwood was first converted via sulfuric acid methanolysis to cellulose pulp and a lignin oil intermediate, which comprises a mixture of lignin oligomers and C5 sugars in the methanol solvent. The impact of reaction temperature (140–200 °C), acid loading (0.24–0.81 wt%, dry biomass), methanol/biomass ratio (2.3/1–15.8/1 w/w) and reaction time (2 h and 0.5 h) was investigated. At high biomass loadings (ratio < 6.3/1 w/w), operation at elevated pressure facilitates delignification by keeping methanol in the liquid phase. A high degree of delignification goes together to a large extent with C5 sugar release, mostly in the form of methyl xylosides. Gel permeation chromatography and heteronuclear single quantum coherence NMR of lignin fractions obtained at high acid (0.81 wt%) and low biomass (15.8/1 w/w) loading revealed extensive cleavage of β-O-4′ bonds during acidolysis at 180 °C for 2 h. At an optimized methanol/biomass ratio of 2.3/1 w/w and acid loading (0.24 wt%), more β-O-4′ bonds could be preserved, i.e., about 33% after 2 h and 47% after 0.5 h. The high reactivity of the extracted lignin fragments was confirmed by a second hydrogenolysis step. Reductive treatment with Pd/C under mild conditions led to disappearance of ether linkages and molecular weight reduction in the hydrotreated lignin oil.
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Hickey, Daniel T., Daniel J. Hayes, J. Tony Pembroke, Michael P. Ryan et James J. Leahy. « The Importance of Extraction Protocol on the Analysis of Novel Waste Sources of Lignocellulosic Biomass ». Energies 14, no 19 (7 octobre 2021) : 6406. http://dx.doi.org/10.3390/en14196406.
Texte intégralRésumé :
As the utilization and consumption of lignocellulosic biomass increases, so too will the need for an adequate supply of feedstock. To meet these needs, novel waste feedstock materials will need to be utilized. Exploitation of these novel feedstocks will require information both on the effects of solvent extraction on the succeeding analysis of potential novel feedstocks and how accurate current methodologies are in determining the composition of novel lignocellulosic feedstocks, particularly the carbohydrate and lignin fractions. In this study, the effects of solvent extraction on novel feedstocks, including tree foliage, tree bark and spent mushroom compost, with 95% ethanol, water and both sequentially were examined. Chemical analyses were carried out to determine the moisture content, ash, extractives, post-hydrolysis sugars, Klason lignin (KL) and acid-soluble lignin (ASL) within the selected feedstocks. The result of extraction could be seen most strongly for Klason lignin, with a strong association between higher levels of Klason lignin levels and greater amounts of non-removed extractives (tree foliage and bark). Higher Klason lignin levels are reported to be due the condensation of non-removed extractives during hydrolysis, hence the lower Klason lignin determinations following extraction are more exact. In addition, total sugar determinations were lower following extractions. This is because of the solubility of non-cell-wall carbohydrates; thus, the determinations following extraction are more accurate representations of structural cell-wall polysaccharides such as cellulose. Such determinations will assist in determining the best way to utilize novel feedstocks such as those analyzed in this work.
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Senila, Lacrimioara, Eniko Kovacs, Daniela Alexandra Scurtu, Oana Cadar, Anca Becze, Marin Senila, Erika Andrea Levei, Diana Elena Dumitras, Ioan Tenu et Cecilia Roman. « Bioethanol Production from Vineyard Waste by Autohydrolysis Pretreatment and Chlorite Delignification via Simultaneous Saccharification and Fermentation ». Molecules 25, no 11 (3 juin 2020) : 2606. http://dx.doi.org/10.3390/molecules25112606.
Texte intégralRésumé :
In this paper, the production of a second-generation bioethanol from lignocellulosic vineyard cutting wastes was investigated in order to define the optimal operating conditions of the autohydrolysis pretreatment, chlorite delignification and simultaneous saccharification and fermentation (SSF). The autohydrolysis of vine-shoot wastes resulted in liquors containing mainly a mixture of monosaccharides, degradation products and spent solids (rich in cellulose and lignin), with potential utility in obtaining valuable chemicals and bioethanol. The autohydrolysis of the vine-shoot wastes was carried out at 165 and 180 °C for 10 min residence time, and the resulted solid and liquid phases composition were analysed. The resulted liquid fraction contained hemicellulosic sugars as a mixture of alpha (α) and beta (β) sugar anomers, and secondary by-products. The solid fraction was delignified using the sodium chlorite method for the separation of lignin and easier access of enzymes to the cellulosic sugars, and then, converted to ethanol by the SSF process. The maximum bioethanol production (6%) was obtained by autohydrolysis (165 °C), chlorite delignification and SSF process at 37 °C, 10% solid loading, 72 h. The principal component analysis was used to identify the main parameters that influence the chemical compositions of vine-shoot waste for different varieties.
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Halysh, Vita, Juan Miguel Romero-García, Alfonso M. Vidal, Tetiana Kulik, Borys Palianytsia, Minerva García et Eulogio Castro. « Apricot Seed Shells and Walnut Shells as Unconventional Sugars and Lignin Sources ». Molecules 28, no 3 (2 février 2023) : 1455. http://dx.doi.org/10.3390/molecules28031455.
Texte intégralRésumé :
The present study focuses on using apricot seeds shells and walnut shells as a potential renewable material for biorefinery in Ukraine. The goal of the research work was to determine the relationship between the chemical composition of solid residues from biomass after acid pretreatment with H2SO4, alkaline pretreatment with NaOH, and a steam explosion pretreatment and the recovery of sugars and lignin after further enzymatic hydrolysis with the application of an industrial cellulase Cellic CTec2. Apricot seeds shells and walnut shells consist of lots of cellulose (35.01 and 24.19%, respectively), lignin (44.55% and 44.63%, respectively), hemicelluloses (10.77% and 26.68%, respectively), and extractives (9.97% and 11.41%, respectively), which affect the efficiency of the bioconversion of polysaccharides to sugars. The alkaline pretreatment was found to be more efficient in terms of glucose yield in comparison with that of acid and steam explosion, and the maximum enzymatic conversions of cellulose reached were 99.7% and 94.6% for the solids from the apricot seeds shells and the walnut shells, respectively. The maximum amount of lignin (82%) in the residual solid was obtained during the processing of apricot seed shells submitted to the acid pretreatment. The amount of lignin in the solids interferes with the efficiency of enzymatic hydrolysis. The results pave the way for the efficient and perspective utilization of shells through the use of inexpensive, simple and affordable chemical technologies, obtaining value-added products, and thus, reducing the amount of environmental pollution (compared to the usual disposal practice of direct burning) and energy and material external dependency (by taking advantage of these renewable, low-cost materials).
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Baig, Khurram Shahzad. « Kinetics of Lignin Removal from the Lignocellulosic Matrix after Ozone Transportation ». Methane 1, no 3 (5 août 2022) : 177–88. http://dx.doi.org/10.3390/methane1030014.
Texte intégralRésumé :
This study presents a new method to remove lignin from wheat straw (lignocellulosic) using the ozonation technique. Lignocellulosic material is a complex biopolymer composed of cellulose, hemicellulose and lignin. Apart from lignin, which acts as a chemical resistant, lignocellulosic is the main resource of cellulose and hemicellulose sugars. The ozonation reaction takes place in a two-phase solid–gas fluidization stainless steel reactor. The focus of this paper is to investigate the kinetics that govern lignin removal from lignocellulosic material after ozonation treatment. The kinetics of lignin removal did not agree with the experimental data until the suggested model is modified to a pseudo-second-order. The results showed that at a higher ozone supply of 150 mg min−1, the surface reaction and intra-particular diffusion were the most significant factors to remove the lignin. Moreover, at a lower ozone supply of 30 mg min−1, the intra-particular diffusion was the only contributor towards lignin removal.
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Zhu, Qianqian, Wei Wei, Jianzhong Sun et Qianqian Wang. « One-pot NaOH/urea pretreatment and saccharification of corn stover for fermentable sugar production ». BioResources 13, no 3 (13 juin 2018) : 5875–82. http://dx.doi.org/10.15376/biores.13.3.5875-5882.
Texte intégralRésumé :
Conversion of lignocellulose into fermentable sugars and other chemicals usually requires multi-step unit operations, such as pretreatment, filtration/washing, and enzymatic saccharification and fermentation, which are the core steps responsible for increased operating expenses. A low-temperature NaOH/urea solution was shown to be an efficient cellulose solvent for overcoming the recalcitrance of lignocellulose by partially or fully converting rigid cellulose I crystallite into the more easily digestible cellulose II structure and by extracting a majority portion of the lignin and xylan from the lignocellulose. Higher yields of fermentable sugars were produced directly from corn stover in one vessel. This one-pot production of fermentable sugars was achieved via a combination process, including pretreatment with low-temperature NaOH/urea solution, pH adjustment, and enzymatic saccharification in a single reactor. This one-pot process liberated 86.3% of glucose and 71.3% of xylose in 24 h at an enzyme loading of 10 FPU/g and solid loading of 5%. Surfactant addition further enhanced enzymatic saccharification. The combination of low-temperature NaOH/urea pretreatment and enzymatic saccharification into a one-pot process is an efficient method for the conversion of lignocellulose into fermentable sugars suitable for conversion into fuels and other chemicals. Further studies related to lignin recovery and economical evaluation will be conducted.
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Ventura, Maria, Marcelo E. Domine et Marvin Chávez-Sifontes. « Catalytic Processes For Lignin Valorization into Fuels and Chemicals (Aromatics) ». Current Catalysis 8, no 1 (21 juin 2019) : 20–40. http://dx.doi.org/10.2174/2211544708666190124112830.
Texte intégralRésumé :
Valorization of lignocellulosic biomass becomes a sustainable alternative against the constant depletion and environmental problems of fossil sources necessary for the production of chemicals and fuels. In this context, a wide range of renewable raw materials can be obtained from lignocellulosic biomass in both polymeric (i.e. cellulose, starch, lignin) and monomeric (i.e. sugars, polyols, phenols) forms. Lignin and its derivatives are interesting platform chemicals for industry, although mainly due to its refractory characteristics its use has been less considered compared to other biomass fractions. To take advantage of the potentialities of lignin, it is necessary to isolate it from the cellulose/ hemicellulosic fraction, and then apply depolymerization processes; the overcoming of technical limitations being a current issue of growing interest for many research groups. In this review, significant data related to the structural characteristics of different types of commercial lignins are presented, also including extraction and isolation processes from biomass, and industrial feedstocks obtained as residues from paper industry under different treatments. The review mainly focuses on the different depolymerization processes (hydrolysis, hydrogenolysis, hydrodeoxygenation, pyrolysis) up to now developed and investigated analyzing the different hydrocarbons and aromatic derivatives obtained in each case, as well as the interesting reactions some of them may undergo. Special emphasis is done on the development of new catalysts and catalytic processes for the efficient production of fuels and chemicals from lignin. The possibilities of applications for lignin and its derivatives in new industrial processes and their integration into the biorefinery of the future are also assessed.
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Yedro, Florencia M., Danilo A. Cantero, Marcos Pascual, Juan García-Serna et M. José Cocero. « Hydrothermal fractionation of woody biomass : Lignin effect on sugars recovery ». Bioresource Technology 191 (septembre 2015) : 124–32. http://dx.doi.org/10.1016/j.biortech.2015.05.004.
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Zhao, Xuebing, et Lihua Zhang. « Production of fermentable sugars and lignin from Siam weed stem ». Journal of Bioscience and Bioengineering 108 (novembre 2009) : S44. http://dx.doi.org/10.1016/j.jbiosc.2009.08.126.
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Adiandri, R. S., R. Purwadi, Hoerudin et T. Setiadi. « Recent Methods in the Pretreatment of Corncob Wastes for Value-Added Bioproducts Carbon Sources ». IOP Conference Series : Earth and Environmental Science 1024, no 1 (1 mai 2022) : 012032. http://dx.doi.org/10.1088/1755-1315/1024/1/012032.
Texte intégralRésumé :
Abstract Corncobs are composed of cellulose, hemicellulose, and lignin. Cellulose and hemicellulose are monomeric sugars that can be utilized as carbon sources for microbial growth and bioproduct formation. However, corncobs present several challenges due to their complex and recalcitrant nature. Addressing these challenges for increased enzymatic and microbial accessibility requires pretreatment methods to break down resistant structures, thus enabling the recovery of fermentable sugars. Different pretreatment methods on corncob wastes have been studied extensively: chemical, physicochemical, and combined pretreatments. Among the developed pretreatment methods, combined pretreatments are the most widely used in the corncob pretreatment process to overcome various limitations in a single pretreatment method. Several combined pretreatment can increase sugar production, shorten processing time and repress inhibitor formation. This review article would assist in determining the best pretreatment method for corncobs according to the advantages, challenges, and effectiveness of various pretreatment methods
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Zulkifli, Zulfah, Nazaitulshila Rasit, Noor Azrimi Umor et Shahrul Ismail. « The effect of A. Fumigatus SK1 and trichoderma sp. on the biogas production from cow manure ». Malaysian Journal of Fundamental and Applied Sciences 14, no 3 (3 septembre 2018) : 353–59. http://dx.doi.org/10.11113/mjfas.v14n3.1066.
Texte intégralRésumé :
Lignocellulosic material consists of lignin, cellulose and hemicellulose. Converting lignocellulosic biomass such as cow manure (CM) into value-added products provides a potential alternative. Hydrolysis of cellulose and hemicellulose is a limiting step during Anaerobic Digestion (AD) of lignocellulosic biomass. Lignin in lignocellulosic biomass is the barrier for hydrolysis, thus limits the biogas production. In this study, the effect of A.Fumigatus SK1 and Trichoderma sp. on enzymatic pre-treatment of CM was investigated with respect to the biogas production. Three set of anaerobic digestion assays were carried out, with a working volume of 500 mL at 35 ± 2°C and 120 rpm. The first set of fermentation contained untreated CM. The second set of fermentation involved addition of A.Fumigatus SK1, and the last set contained Trichoderma sp. Several analysis were conducted to determine the biomethane potential (BMP), anaerobic biodegradability, reducing sugars concentration and lignin removal of CM before and after pre-treatment. Result showed that, among both evaluated pre-treatment methods, CM treated with Trichoderma sp. gave the highest methane potential with 0.023 LCH4-STP g VS-1 compared to CM treated with A.Fumigatus SK1(0.011 LCH4-STP g VS-1). A good correlation have been found in this study between lignin removal and reducing sugar produced where, the total lignin removal after treated with Trichoderma sp. was 60% followed by 43% after treated with A.Fumigatus SK1.The reducing sugar produced after pre-treated with Trichoderma sp. and A.Fumigatus SK1 was about 9.59 and 4.91 μmol glucose, respectively. These results collectively suggested that CM treated with Trichoderma sp. could be a better pre-treatment method for the higher methane production in anaerobic mono-digestion process.
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Ko, Chun-Han, Fang-Jing Chen, Wan-Jyung Liao et Tzenge-Lien Shih. « Impacts of lignin contents and yeast extract addition on the interaction between spruce pulps and crude recombinant Paenibacillus endoglucanase ». BioResources 6, no 1 (25 janvier 2011) : 853–66. http://dx.doi.org/10.15376/biores.6.1.853-866.
Texte intégralRésumé :
Crude recombinant Paenibacillus endoglucanase was employed to investigate its ability to gain access into and to degrade spruce pulps having different lignin and pentosan contents. Since yeast extract is commonly present in the simultaneous saccharification and fermentation processes as a nitrogen source, its effect on the accessibility and degradability of crude endoglucanase was examined. Pulps with more lignin contents adsorbed more overall proteins. More protein impurities other than the recombinant Paenibacillus endoglucanase were found to be preferentially adsorbed on the surfaces of pulp with higher lignin contents. The addition of yeast extracts further enhanced the above trends, which might reduce the non-productive binding by pulp lignin. Pulps with more lignin contents were more difficult to be degraded by the crude endoglucanase; the reductions of degree of polymerization (DP) for pulps were more sensitive to the dosage of endoglucanase applied. The presence of yeast extracts increased the DP degradation rate constants, but decreased the release of reducing sugars during hydrolysis for pulp with higher lignin contents.
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Weidener, Dennis, Arne Holtz, Holger Klose, Andreas Jupke, Walter Leitner et Philipp M. Grande. « Lignin Precipitation and Fractionation from OrganoCat Pulping to Obtain Lignin with Different Sizes and Chemical Composition ». Molecules 25, no 15 (22 juillet 2020) : 3330. http://dx.doi.org/10.3390/molecules25153330.
Texte intégralRésumé :
Fractionation of lignocellulose into its three main components, lignin, hemicelluloses, and cellulose, is a common approach in modern biorefinery concepts. Whereas the valorization of hemicelluloses and cellulose sugars has been widely discussed in literature, lignin utilization is still challenging. Due to its high heterogeneity and complexity, as well as impurities from pulping, it is a challenging feedstock. However, being the most abundant source of renewable aromatics, it remains a promising resource. This work describes a fractionation procedure that aims at stepwise precipitating beech wood (Fagus sp.) lignin obtained with OrganoCat technology from a 2-methyltetrahydrofuran solution, using n-hexane and n-pentane as antisolvents. By consecutive antisolvent precipitation and filtration, lignin is fractionated and then characterized to elucidate the structure of the different fractions. This way, more defined and purified lignin fractions can be obtained. Narrowing down the complexity of lignin and separately valorizing the fractions might further increase the economic viability of biorefineries.