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Weight-average (Mw) and number-average (Mn) molar masses and dispersity (Ɖ = Mw/Mn) of the hemicelluloses extracted from a sulfite pulp.
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![Biopolymer composition of common softwood and sulfite pulps [2,10]...](publication/352687954/figure/tbl1/AS:1037871179898882@1624459180572/Biopolymer-composition-of-common-softwood-and-sulfite-pulps-2-10-compared-to-the-RYAM_Q320.jpg)
Hemicelluloses were extracted from a softwood acid sulfite pulp in a three-step procedure. Further delignification step resulted in a holocellulose pulp containing only 1.7 wt.% of the lignin left. Cold caustic extraction (CCE) with 18 wt.% NaOH at 60 °C for 1 h was performed to solubilize hemicelluloses of the holocellulose. An unbleached cellulos...
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... first population eluted at 23 min could correspond either to aggregates of branched polysaccharides or longer cellulose chains, whereas elutions of the extracted hemicelluloses were attributed at 28 min. The average molar masses values MW, Mn and dispersity Ɖ of the isolated hemicelluloses are given in Table 4. The hemicelluloses displayed MW values varying between 18,900 and 30,000 g/mol, with a dispersity of 1.4 to 2.0. ...Citations
... In process streams of chemical pulping, they are present in the form of galactoglucomannan, glucomannan and arabinoglucuronoxylan, and glucuronoxylan. Some applications of hemicelluloses include oxygen barrier films for packaging, paper additives, food ingredients, or coatings [13][14][15][16][17]. However, many laboratory products based on hemicellulose have not been scaled up yet due to their low availability [18]. ...
The pulp and paper industry is one of the biggest industry sectors worldwide, whose market growth is expected to reach 370.12 billion USD by 2028. However, as a water-intensive process, the pulp and paper production generate huge volumes of contaminated effluents, some of which contain dissolved high-value chemical compounds, such as lignin, hemicellulose, or carboxylic acids. These compounds can be recovered using membrane operations. Thus, membrane operations represent a method to valorize effluents and byproducts from this industry sector and narrow the gap between biorefinery models and the pulp and paper production as an integrated biorefinery. The present review reviews the state-of-the-art-research and the state-of-the-art applications of membrane operations in the pulp and paper industry.
... The second region displays signals for non-substituted xylose units (4.49 ppm) and for glucuronic-acid-substituted β-xylose (4.64 ppm) [66][67][68]. For the third region, the assignment was considered as follows: H2Ara-4.11 ...
The alkaline extraction of hemicelluloses from a mixture of three varieties of wheat straw (containing 40.1% cellulose, 20.23% xylan, and 26.2% hemicellulose) was analyzed considering the following complementary pre-treatments: freeze–thaw cycles, microwaves, and ultrasounds. The two cycles freeze–thaw approach was selected based on simplicity and energy savings for further analysis and optimization. Experiments planned with Design Expert were performed. The regression model determined through the response surface methodology based on the severity factor (defined as a function of time and temperature) and alkali concentration as variables was then used to optimize the process in a multi-objective case considering the possibility of further use for pulping. To show the properties and chemical structure of the separated hemicelluloses, several analytical methods were used: high-performance chromatography (HPLC), Fourier-transformed infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H-NMR), thermogravimetry and derivative thermogravimetry analysis (TG, DTG), and scanning electron microscopy (SEM). The verified experimental optimization result indicated the possibility of obtaining hemicelluloses material containing 3.40% glucan, 85.51% xylan, and 7.89% arabinan. The association of hot alkaline extraction with two freeze–thaw cycles allows the partial preservation of the hemicellulose polymeric structure.
... ii. As cellulose is alkali resistant, alkali cooking progress can remove lignin, pectin, hemicellulose and water-soluble matter (Qian et al., 2008;Abdelaziz et al., 2017;Renard et al., 1990;Vincent et al., 2021). iii. ...
A new ramie degumming method, N-Hydroxyphthalimide (NHPI) catalytic oxidation degumming method (NCODM), was proposed to solve the environmental pollution problems as well as the energy consumption problems of the traditional alkaline degumming method (TADM) and the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation degumming method (TODM). In this paper, the effect of parameters on the properties of ramie fibers degummed by NCODM was investigated. Then, the degumming process was optimized by comparing with the different degumming methods using central composite design method. The results showed that the H2O2 concentration and reaction time were significant factors that determined the properties of ramie fibers. The optimum H2O2 concentration was 16.70 g/L and the optimum reaction time was 19.38 min. The time required for NCODM was only 79.38 min, which was 26.46% and 62.19% of that of TADM (300 min) and TODM (127.64 min), respectively. Moreover, the chemical oxygen demand (COD) value of the wastewater from NCODM was 31% and 3% lower than that of TADM and TODM, respectively. Therefore, NCODM has great potential to replace the TADM and TODM for ramie degumming.
... Therefore, the signals are attributed to β-xylose (X), glucuronic acid substituted β-xylose (XG), β-glucose (G), and α-glucuronic acid (AG) ( Figure S4 and Table S1 in Supplementary Materials). All structures for these units have been reported in the literature [85]. The observable signals for α-L-arafuranosyde residues (Ara) are assigned to the anomeric proton H1 Ara at 5.35 ppm and for H4 Ara proton (see Figure S4 in Supplementary Materials) at 4.27 ppm [86]; the remaining signals overlap with other signals in the spectrum. ...
... The signals in the interval 4.49-4.47 (peak at 4.48 ppm) are due to the anomeric proton H1 X of β-D-xylopyranoside residues (or β-xylose, noted above with X) [85,87,88], and the remaining signals are assigned as follow: 4.12 ppm, H5eq X ; 3.80 ppm, H4 X ; 3.55 ppm, H3 X ; 3.38 ppm, H5axx3.30 ppm, H2 X . ...
In this paper, we describe an experimental study on the hot alkali extraction of hemicelluloses from wheat straw and corn stalks, two of the most common lignocellulosic biomass constituents in Romania. The chemical compositions of the raw materials were determined analytically, and the relevant chemical components were cellulose, hemicelluloses, lignin, and ash. Using the response surface methodology, the optimum values of the hot alkaline extraction parameters, i.e., time, temperature, and NaOH concentration, were identified and experimentally validated. The physicochemical characterization of the isolated hemicelluloses was performed using HPLC, FTIR, TG, DTG, and 1H-NMR spectroscopy. The main hemicellulose components identified experimentally were xylan, arabinan, and glucan. The study emphasizes that both corn stalks and wheat straw are suitable as raw materials for hemicellulose extraction, highlighting the advantages of alkaline pretreatments and showing that optimization methods can further improve the process efficiency.
... In addition, total extractives were quantified in ethanol:toluene (2:1, v/v) according to TAPPI Standards & Methods (T 204 om-88), with adaptations. Finally, the cellulose and hemicellulose content were characterized by the gravimetric method described by (Vincent et al., 2021) with adaptations, using two steps: first step (delignification) using NaClO 2 and second step using a strong base solution, in this case KOH (hemicellulose hydrolysis). The results are included in Table 1. ...
The waste-to-energy (WTE) valorization pathway of Caryocar brasiliense (pequi) seeds was investigated via pyrolysis , gasification, and transesterification to understand its potential as biochar, syngas, and biodiesel. First, the pyrolysis (300-700 • C) was conducted in N 2 atmosphere for pequi seeds (PS) and pequi seeds without its ex-tractives (PSWE), characterizing its biochar properties. The PSWE was then gasified at 1000 • C under O 2 /N 2 , O 2 / CO 2 /N 2 and O 2 /H 2 O/N 2 atmospheres to evaluate the characteristics of the producer gas. The PS extractives were then transesterified and characterized for biodiesel production. Finally, a multiple-criteria decision analysis assessed the PS products' potential within the thermochemical routes. The results evidenced better biochar (up to 22.29% HHV enhancement, higher mass and energy yield, up to 75.9 and 85.5% reduction of O/C and H/C, respectively, and enriched N content) via PSWE pyrolysis than PS considering biofuel application and optimistic perceptions for soil amendment. This indicates that the preceding extraction of vegetal fat from PS strengthens the WTE by including further processing of extracted oil. The produced syngas under O 2 /H 2 O/N 2 gasification atmosphere showed better applicability as a biofuel (16.37 MJ⋅kg − 1 lower heating value, 107.33% cold gas efficiency, and 113.55% carbon conversion efficiency) with up to 24% higher success rate. The transesterification of the extractives revealed its potential (98% conversion rate) for use as feedstock for in situ power generation, or blended for biodiesel production. The results provide insights into the circular economy in agro-extractivist communities that may support Brazil's small and medium agro-food industries with their energy demands.
... Ecological concern and new environmental protection regulations have required the replacement of inorganic fillers with natural fillers in polymer composites. The reuse of waste or by-products in agro-food industry can increase economic value and environmental benefits and better highlight sustainability [9][10][11][12]. The main reasons for the use of natural fillers in the development of polymer composites were: low cost, sustainability [13], low density, non-toxicity and the fact that they are less abrasive during processing [14]. ...
The production of composite materials through the reuse of waste or by-products from the agri-food industry will be a challenge for environmental protection. This study focuses in that direction. In the first stage, composites were made with the hybrid resin matrix (with three major volume proportions of natural Dammar resin and epoxy resin) and the reinforcing from shredded shells of sunflower seeds. Based on the tensile and compressive stresses, the stress–strain and strain–strain diagrams were obtained. The surface area of the rupture was investigated with stereo-microscopic analysis, and the absorption/loss of water was studied with a high precision balance. The vibration behavior was investigated experimentally, determining the damping coefficient and its own frequency. In the second stage, the study of these materials was extended. Sandwich composites were made with the same type of hybrid matrix as in the first stage. The core was made of shredded shells of sunflower seeds and the outer faces of linen fabric. These composites were applied to the bend (in three points), being obtained the force-deformation diagrams. The determined mechanical properties allow the complete or partial realization of these composites of some furniture components or of some equipment used in the field of constructions.
... Modified starch (hydroxypropyl starch, HPS) is one of the most renewable resources that can be obtained by the propylation reaction of starch [13,[31][32][33]. HPS has the advantages of nontoxicity and biocompatibility [34]. On the other hand, polyurethane (PU), is employed in biomedical applications due to its excellent mechanical characteristics, and processing adaptability [35,36]. ...
... At two different magnifications, the particle shape of the produced AgNPs was examined, and the results are displayed in Figure 2a,b. Mostly, AgNPs produced via polymer reduction and stabilization result in particles distribution size less than 20 nm, which agrees with our findings [34]. The average distribution size of AgNPs from TEM images was calculated using Image J4s software and it was around 6 nm ( Figure 2c). ...
Fabrication of electrospun nanofibers based on the blending of modified natural polymer, hydroxyl propyl starch (HPS) as one of the most renewable resources, with synthetic polymers, such as polyurethane (PU) is of great potential for biomedical applications. The as-prepared nanofibers were used as antimicrobial sheets via blending with biosynthesized silver nanoparticles (AgNPs), which were prepared in a safe way with low cost using the extract of Nerium oleander leaves, which acted as a reducing and stabilizing agent as well. The biosynthesized AgNPs were fully characterized by various techniques (UV-vis, TEM, DLS, zeta potential and XRD). The obtained results from UV-vis depicted that the AgNPs appeared at a wavelength equal to 404 nm affirming the preparation of AgNPs when compared with the wavelength of extract (there are no observable peaks). The average particle size of the fabricated AgNPs that mediated with HPS exhibited a very small size (less than 5 nm) with excellent stability (more than −30 mv). In addition, the fabricated nanofibers were also fully characterized and the obtained data proved that the diameter of nanofibers was enlarged with increasing the concentration of AgNPs. Additionally, the findings illustrated that the pore sizes of electrospun sheets were in the range of 75 to 350 nm. The obtained results proved that the presence of HPS displayed a vital role in decreasing the contact angle of PU nanofibers and thus, increased the hydrophilicity of the net nanofibers. It is worthy to mention that the prepared nanofibers incorporated with AgNPs exhibited incredible antimicrobial activity against pathogenic microbes that actually presented in human wounds. Moreover, P. aeruginosa was the most sensitive species to the fabricated nanofibers compared to other tested ones. The minimal inhibitory concentrations (MICs) values of AgNPs-3@NFs against P. aeruginosa, and E. faecalis, were 250 and 500 mg/L within 15 min, respectively.
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.
The purpose of this study was to characterize the biological activity of konjac glucomannan (KGM) according to its molecular weight change. KGM-degrading bacterial strain, N3 was isolated from soil and named Bacillus aerophilus following 16S rDNA sequencing and homology analysis. KGMase, a thermophilic konjac glucomannan-degrading enzyme, was partially purified by treating the culture supernatant of strain B. aerophilus N3 with 50% ammonium sulfate followed by rigorous heating at 75 °C for 30 min. The molecular weight (MW) of KGMase was determined to be approximately 41,000 by silver staining following sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). The biochemical properties stipulated that KGMase is optimally active at 45 °C and pH 6.5 which shows the high temperature and pH stability of KGMase. Manno-oligosaccharides (MOs) derived from the hydrolysis of KGM by KGMase showed a concentration-dependent increase in tyrosinase activity. MOs are bioactive compounds derived from the hydrolysis of KGM by the thermophilic KGMase of B. aerophilus and the outcomes of our study demonstrated that MOs will be suitable for application in the cosmetics industry.
Extraction of hemicelluloses from biomass with pressurized hot‐water employs the mechanism of autohydrolysis for molecular weight reduction. In a pilot‐scale extraction of depectinized apple pomace, molecular weight was 30 kDa with a broad mass distribution including monomers and their degradation products. Ultrafiltration with sequential use of ceramic membranes with decreasing cut‐off yielded a suitable fraction with molecular weight of 9 kDa representing 10 % of the extracted hemicelluloses. Further autohydrolytic treatment of the extracted hemicellulose decreases molecular weight while increasing the mass of degradation products. For a series of hydrolysates sequential filtration through ceramic membranes was further tested for fractionation and purification. The efficiency of this fractionation was analyzed by size exclusion chromatography and a total mass balance of the ultrafiltration process is given as an evaluation for suitability of purifying and fraction glycans.
