Xylan-rich Hemicelluloses Research Articles

Hemicellulose-based nanoaggregate-incorporated biocompatible hydrogels with enhanced mechanical properties and sustained controlled curcumin release behaviors

Local drug delivery has generated considerable interest due to its controlled and sustained drug release at the target site on demand. Nanoaggregate-incorporated composite hydrogels are desirable as local drug delivery systems; however, it is difficult to achieve sustained and controlled hydrophobic drug release and superior mechanical properties in one system. Herein, a “smart” composite hydrogel was synthesized by incorporating hemicellulose-based nanoaggregates into a double network consisting of alginate/Ca2+ and polyacrylic acid-co-dimethylaminoethyl methacrylate [P(AA-co-DMAEMA)]. Hemicellulose-based nanoaggregates were assembled from xylan-rich hemicellulose laurate methacrylate (XH-LA-MA) polymers and entrapped into the hydrogel framework via chemical fixation. Another composite hydrogel with physically embedded hemicellulose laurate (XH-LA) nanoaggregates was prepared as a comparison. Accordingly, covalently cross-linked XH-LA-MA nanoaggregates in hydrogels resulted in a denser pore structure and reinforced mechanical properties. Nanoaggregate diffusion analysis revealed that covalent bonding between the nanoaggregates and the hydrogel framework contributed to prolonged diffusion behavior. Curcumin (Cur)-loaded XH-LA-MA composite hydrogels enabled sustained Cur release in simulated body fluid and showed stimulus responsiveness toward ethylenediaminetetraacetic acid (EDTA) and/or glutathione (GSH). All the composite hydrogels were biocompatible, as verified by Cell Counting Kit-8 (CCK-8) assay against NIH/3T3 cells. These composite hydrogels hold great potential as a promising dosage form for biomedical applications.

Dissolution behavior of arabinoxylan from sugarcane bagasse in tetrabutylammonium hydroxide aqueous solution

Arabinoxylan is one of the main components of xylan-rich hemicellulose of sugarcane bagasse. The study on the dissolution behavior of arabinoxylan from sugarcane bagasse (AXSB) is beneficial to its efficient utilization. The dissolution behavior of AXSB in a 50% TBAH aqueous solution was investigated by small angle X-ray scattering and rheological methods. SAXS analysis showed that the radius of gyration (Rg) of AXSB is between 8.5 nm and 21.6 nm, and Rg has a larger value with the rising AXSB concentration. Rheological measurements showed that AXSB is completely dissolved in TBAH aqueous solution at low concentration, aggregating after reaching a certain concentration. The estimated critical concentration is approximately 0.033 g mL−1. The rheological curves at the high concentration indicated shear thinning behavior, causing the failure of the Cox-Merz rule. The storage modulus grows gradually with the increasing AXSB concentration, inferring the probable formation of AXSB aggregation in TBAH aqueous solution.

Influence of pH and ionic strength on the aggregation behaviors of xylan rich hemicelluloses with alkaline lignins

The evolution of xylan-rich hemicelluloses (XH) aggregation behaviors in the presence of alkaline lignins (AL) under a wide range of pH values and NaCl concentration were investigated via dynamic light scattering and turbidity measurements. XH isolated from wheat straw contain a xylose backbone with arabinose side chains and a small amount of phenol groups. XH tend to aggregate in solution due to their low ratio of arabinose to xylose and hydrophobic phenol groups. AL interact with XH through the phenol groups bonded to the hemicellulose main chain to form an AL-XH complex. As the pH value decreases, the particle size and turbidity of AL, XH and their bonded complex all increase. The size of the AL-XH complex agglomerate is greater than the size of a XH at the same pH value, which indicates that the self-assembly of lignin molecules initiate the aggregation of XH. The particle size and turbidity of XH and AL-XH complexes increase as the XH concentration increase. At low pH values, e.g., 6.0, the particle size of the AL-XH complex more obviously increases compared to the XH particles. The size and turbidity of the AL, XH, and AL-XH complex agglomerates increased as the NaCl concentration increased.

Production and characterization of lignocellulosic fractions from sisal waste

An integrated fractionation process, UV-catalyzed hydrogen peroxide pretreatment (UHP) with subsequent alkali and acidic ethanol extraction, was developed to consecutively recover cellulose, hemicellulose, lignin and pretreated liquid fractions from sisal waste. These fractions serve as a viable source of high-value industrial chemicals. Delignification rate reached approximately 80 % under the UHP pretreatment with 0.1 mL/g H2O2 for 6 h. The pretreated sisal waste was further fractionated into four parts, cellulose (35.5 g/100 g sisal waste), xylan-rich hemicellulose (12.5 g/100 g sisal waste), acid-insoluble lignin (5.7 g/100 g sisal waste) and the liquid fraction (21.0 g/100 g sisal waste). The cellulose fraction was in high purity with increased crystalline index of 51.4 %, and the hemicellulose fraction was rich in xylan. The lignin fraction had the GSH-type structure with some ferulic acid residues bound mainly via β-O-4 linkages. The liquid fraction had a high content of phenolic compounds (16.26∼41.88 mg GAE/L) with strong antioxidant activities, 11.16∼18.48 μmol TE/L reducing power, 66.78∼82.84 μmol TE/L hydroxyl radical scavenging and 14.83∼46.67 μmol TE/L ABTS radical scavenging.

Antibacterial nanobiocomposite based on halloysite nanotubes and extracted xylan from bagasse pith

In this study, the antibacterial polyelectrolyte carboxymethyl xylan/chitosan (CMX/CS) films incorporated with halloysite nanotubes (HNTs) and Origanum vulgare essential oil (OEO) were prepared and then characterized. Xylan-rich hemicelluloses (62.23%) were extracted from sugarcane bagasse pith and then subjected to carboxymethylation. FTIR analysis revealed the successful modification of hemicelluloses. The irregular white spots in SEM images of nanobiocomposites revealed the entrance of HNTs into the polymer matrix. EDX maps manifested that the density of Si and Al atoms increased, as the amount of HNT increased. The observed discontinuities for EO-containing nanobiocomposites in the SEM images may be attributed to the hydrophobic nature of EO. The barrier properties of the nanocomposites improved by incorporation of HNTs and O. vulgare. The tensile strength of nanocomposite improved significantly by incorporating HNT. EO/HNT-containing films exhibited a higher antibacterial activity against selected bacteria than HNT-containing films.

Karakterisasi Enzim Xilanase dari Isolat Bacillus sp. UJ131 di Hutan Mangrove Margasari Lampung Timur sebagai Kandidat Probiotik

<strong>Characterization of Xilanase Enzyme by Bacillus sp. UJ131 A Probiotic Candidate from the Mangrove of Margasari, East Lampung</strong>. Mangrove are known to have high biodiversity as a potential location for exploration of enzyme-producing bacteria, one of which is the xylanase enzyme. Xylanase is an enzyme that hydrolyzes the xylan-rich hemicellulose substrate. This research aims to produce and know the character of xylanase enzyme by Bacillus sp. UJ131 isolate which was isolated from the oriental shrimp in Margasari mangrove forest of East Lampung. Xylanase enzymes are produced from the bacteria by growing them in sea water complete (SWC) broth containing xylan beechwood. Characterization xylanase enzyme consist of pH, temperature, and metal ions. The results showed that xylanase had an optimal time of 18 hours with xylanase activity of 0.18 U/ml, and optimally at pH 6 and temperature 70°C. The addition of Mn2+ and Ca2+ ions increase enzyme activity, but Fe3+, Cu2+ and Mg2+ ions decrease xylanase enzyme activity. At a maximum reaction speed of 0.25 U/ml, the xylanase enzyme can produce 1.30 μM xylose per minute

Synthesis of hemicellulose hydrogels with tunable conductivity and swelling behavior through facile one-pot reaction

The conductive hemicellulose hydrogels (CHHs) were achieved by incorporating carboxyl terminated aniline pentamer (CTAP) into the hydrophilic xylan-rich hemicellulose networks with epichlorohydrin. CHHs were obtained by facile one-pot reaction in water at ambient temperature. The successful synthesis of CTAP was confirmed by FT-IR, 1H NMR, and UV–vis spectra. All the hydrogels reached their equilibrium-swollen state within 12 h. The morphology and the thermal stability of CHHs were adjusted by the addition of CTAP. The conductivities of CHHs could also be tuned from 8.92 × 10−5 to 2.11 × 10−3 S/m by adding the blending amounts of the CTAP from 0 to 50% mass ratio while simultaneously altering the equilibrium swelling ratio from 28.1 to 15.8. CHHs showed homogeneous porous structure, tunable swelling behavior, controllable conductivity, and good thermal stability. These results highlight that CHHs are attractive candidates to be used in biomedical applications.

Compositional evaluation of selected agro-industrial wastes as valuable sources for the recovery of complex carbohydrates

Re-utilization of various agro-industrial wastes is of growing importance from many aspects. Considering the variety and complexity of such materials, compositional data and compliant methodology is still undergoing many updates and improvements.Present study evaluated sugar beet pulp (SBP), walnut shell (WS), cocoa bean husk (CBH), onion peel (OP) and pea pods (PP) as potentially valuable materials for carbohydrate recovery. Macrocomponent analyses revealed carbohydrate fraction as the most abundant, dominating in dietary fibres. Upon complete acid hydrolysis of sample alcohol insoluble residues, developed procedures of high performance thin-layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) coupled with 3-methyl-1-phenyl-2-pyrazolin-5-one pre-column derivatization (PMP-derivatization) were used for carbohydrate monomeric composition determination. HPTLC exhibited good qualitative features useful for multi-sample rapid analysis, while HPLC superior separation and quantification characteristics. Distinctive monomeric patterns were obtained among samples. OP, SBP and CBH, due to the high galacturonic acid content (20.81%, 13.96% and 6.90% dry matter basis, respectively), may be regarded as pectin sources, while WS and PP as materials abundant in xylan-rich hemicellulose (total xylan content 15.53%, 9.63% dry matter basis, respectively). Present study provides new and valuable compositional data for different plant residual materials and a reference for the application of established methodology.

Isolation and Hydrolysis Xylan from Soybean Waste with Endo-β-1,4-D-Xilanase of Bacillus sp. From Soil Termite Abdomen

Abstract Soybean waste is by product in production of tofu and soymilk. Soybean waste commonly dumps directly to the water sewer and made environmental problems like eutrotification. Soybean waste contains 23% hemicellulose, 16% cellulose dan 28% protein. Xylan rich hemicellulose is potential source of xylooligosacharides (XOS). XOS was known as functional food with prebiotic activities. In this research, xylan was isolated from soybean waste then hydrolyzed by endoxylanase enzyme of Bacillus sp from soil termite abdominal. At the beginning, Soybean waste was processed by reflux to exclude lipid compound. Then process continued by alkaline treatment using NaOH 4-18% to separate the xylan from lignocellulose complex. Isolated xylan was hydrolyzed by endo-β-1,4-D-xylanase to get XOS. Hydrolised product analysed by TLC and HPLC. TLC analysis shown thick spot confirmed as xylopentaose (X5) compare to the Rf of the standard compound. HPLC data supported these analyses with the result of X5 as highest component (6959,88 ppm) beside the other XOS such as xylobiosa (X2) 6,34 ppm and xylosa (X1) 7,1 ppm. With the same enzyme, the result of hydrolyzed of soybean wastes xylan is not different with hydrolysed of oat spelt xylan, the common xylan source.

Xylan–cellulose films: Improvement of hydrophobicity, thermal and mechanical properties

Xylan-rich hemicellulose from corn cob has been used for new material elaboration. Commercial cellulose was used as reinforcement in different percentages to improve properties of the films. Two types of composites were elaborated by solvent casting. Hydrophilic films, composed by bleached hemicellulose (BH), unmodified cellulose and glycerol as plasticizer, and hydrophobic films formed by acetylated bleached hemicellulose (BAH) and acetylated cellulose. The degree of substitution of BAH was 1.8 and acetylated cellulose presented a degree of substitution of 0.54. Thermal and mechanical properties of films were analyzed. A significant improvement was observed in the thermal behavior of hydrophobic films (Tmax∼368°C) respect to hydrophilic films (Tmax∼300°C). Although the addition of cellulose clearly increase the properties of both type of films, hydrophobic films (Young's modulus ∼2300MPa, strength ∼44.1MPa, strain at break ∼5.7%) showed better mechanical properties than hydrophilic films (Young's modulus ∼3MPa, strength ∼3.3MPa, strain at break ∼5.3%).

Non-cellulosic heteropolysaccharides from sugarcane bagasse – Sequential extraction with pressurized hot water and alkaline peroxide at different temperatures

The xylan-rich hemicellulose components of sugarcane bagasse were sequentially extracted with pressurized hot-water extraction (PHWE) and alkaline peroxide. The hemicelluloses were found to contain mainly arabinoxylans with varying substitutions confirmed by different chemical and spectroscopic methods. The arabinoxylans obtained from PHWE were found to be more branched compared to those obtained after alkaline extraction. Sequential extraction could be useful for the isolation of hemicelluloses with different degree of branching, molar mass, and functional groups from sugarcane bagasse, which can be of high potential use for various industrial applications.

Synthesis and characterization of cyanoethyl hemicelluloses and their hydrated products

A novel type of hemicellulosic derivative, cyanoethyl hemicelluloses (CEH), derived from xylan-rich hemicelluloses and acrylonitriles was successfully prepared in aqueous sodium hydroxide. The reaction was performed under various reaction conditions such as temperature, time, the amount of sodium hydroxide, and the molar ratio of acrylonitrile to anhydroxylose units in hemicelluloses, and the relationship between reaction condition and DS of the CEH was investigated in detail. A series of CEH with degree of substitution of cyanoethyl (DSC≡N) ranging from 0.23 to 1.64 were obtained. Importantly, CEH can undergo various reactions and convert into other macromolecules with functional groups like carboxylic acids, amine, aldehyde etc. In this work, H2O2/K2CO3/DMSO was used to hydrate CEH into carbamoylethyl hemicelluloses at room temperature. FT-IR, 1H and 13C NMR spectra confirmed the introduction of cyanoethyl groups into the hemicelluloses backbone and the presence of carbamoylethyl groups in the hydrated product. In addition, in the nucleophilic addition reaction, the hydroxyl groups at C-3 position of the anhydroxylose units were more active than these at C-2. TGA/DTG showed that CEH had lower thermal stability than hemicelluloses. This work provided a new macromolecule which can be used as a versatile platform for producing other functional macromolecules.

Functional Modification of Xylan-Rich Hemicelluloses in Ionic Liquid

Xylan-rich Hemicelluloses (XH) isolated from wheat straw were converted to functional biopolymers by modification using succinic anhydride (SA) as reactant without catalyst in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. The reaction was performed under various conditions such as different temperatures, different times, and the different amounts of SA, and the effect of reaction factors on the degree substitution (DS) of products were discussed. The product had the maximum DS of 1.80. The structure of modified hemicellulosic derivatives (MD) was actually confirmed by13C NMR spectroscopy. The thermal behavior of MD was monitored by means of thermogravimetry (TG) and differential thermal analysis (DTA), and the thermal stability of MD was lower than XH.

Isolation of a gastroprotective arabinoxylan from sugarcane bagasse

After industrial processing, one-third of sugarcane culms is converted into residual bagasse. The xylan-rich hemicellulose components of the bagasse were extracted with hot aqueous alkali (AX-CRUDE). Approximately 82% of the extracted hemicelluloses was precipitated with ethanol (AX-PET). Both AX-CRUDE and AX-PET contained an arabinoxylan as confirmed by 13C NMR and methylation analysis. Fraction AX-PET was fed to female Wistar rats with ethanol-induced gastric lesions. Oral administrations of 30, 100, and 300mg/kg reduced the gastric lesion area by over 50%, and replenished ethanol-induced depletion of glutathione. The polysaccharide also increased mucus production by over 70%, indicating its cytoprotective action on experimentally induced gastric ulcers. These findings are significant, since a biologically active compound can be extracted in high yields from an abundant, readily available residue.

Nanocomposite Films Based on Xylan-Rich Hemicelluloses and Cellulose Nanofibers with Enhanced Mechanical Properties

Interest in xylan-rich hemicelluloses (XH) film is growing, and efforts have been made to prepare XH films with improved mechanical properties. This work described an effective approach to produce nanocomposite films with enhanced mechanical properties by incorporation of cellulose nanofibers (CNFs) into XH. Aqueous dispersions of XH (64-75 wt %), sorbitol (16-25 wt %), and CNF (0-20 wt %) were cast at a temperature of 23 °C and 50% relative humidity. The surface morphology of the films was revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal properties and crystal structure of the films were evaluated by thermal analysis (TG) and X-ray diffraction (XRD). The surface of XH films with and without CNF was composed primarily of nanonodules, and CNFs were embedded in the XH matrix. Freeze-dried XH powder was amorphous, whereas the films with and without CNF showed a distinct peak at around 2θ = 18°, which suggested that XH molecules aggregated or reordered in the casting solution or during water evaporation. Furthermore, the nanocomposite films had improved thermal stability. XH film with 25 wt % plasticizer (sorbitol, based on dry XH weight) showed poor mechanical properties, whereas incorporation of CNF (5-20 wt %, based on the total dry mixture) into the film resulted in enhanced mechanical properties due to the high aspect ratio and mechanical strength of CNF and strong interactions between CNF and XH matrix. This effective method makes it possible to produce hemicellulose-based biomaterials of high quality.

Xylan-rich Hemicelluloses-graft-Acrylic Acid Ionic Hydrogels with Rapid Responses to pH, Salt, and Organic Solvents

Exploitation of biomaterials derived from renewable resources is an important approach to address environmental and resource problems in the world today. In this paper, novel ionic hydrogels based on xylan-rich hemicelluloses were prepared by free radical graft copolymerization of acrylic acid (AA) and xylan-rich hemicelluloses (XH) by using N,N-methylene-bis(acrylamide) (MBA) as cross-linker and ammonium persulfate/N,N,N',N'-tetramethylethylenediamine (APS/TMEDA) as redox initiator system. The network characteristics of the ionic hydrogels were investigated by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), as well as by determination of mechanical properties, swelling, and stimuli responses to pH, salts, and organic solvents. The results showed that an increase in the MBA/XH or AA/XH ratio resulted in higher cross-linking density of the network and thus decreased the swelling ratio. Expansion of the network hydrogels took place at high pH, whereas shrinkage occurred at low pH or in salt solutions as well as in organic solvents. The ionic hydrogels had high water adsorption capacity and showed rapid and multiple responses to pH, ions, and organic solvents, which may allow their use in several areas such as adsorption, separation, and drug release systems.

The Preparation and Application of the Cationic Biopolymer Based on Xylan-Rich Hemicelluloses from Agricultural Biomass

During the last few years increasing attention has been paid to the exploitation of hemicelluloses as biopolymer resources because they are available in very large amounts in organic wasters from renewable forest and agricultural biomass. The efficient method to prepare the cationic biopolymers based on xylan-rich hemicelluloses from agricultural biomass has been developed in this paper. These biopolymers with cationic functional groups, having many good properties such as solubility, bio-degradation, cationic or ampholytic polymers, were synthesized by the chemical modification of sugarcane bagasse xylan-rich hemicelluloses with CHMAC and preferably with ETA in different media. These biopolymers based on xylan-rich hemicelluloses with the degree of substitution (DS) up to 0.55 could be obtained by varying the molar ratio of ETA or CHMAC to anhydroxylose units in hemicelluloses from 0.5 to 3.0. 13C NMR confirmed that cationic groups were grafted onto the backbone of hemicelluloses. In addition, their applications in papermaking as dry strengthen agent were investigated. It was found that these biopolymers could obviously improve the physical properties of hand sheets formed from old corrugated container pulp fibres. These results mentioned above highlight the remarkable potential for using the hemicelluloses-based biopolymers as wet end additives in papermaking.

Rapid Carboxymethylation of Xylan-Rich Hemicelluloses by Microwave Irradiation

Rapid carboxymethylation of xylan-rich hemicelluloses from wheat straw biomass with sodium monochloroacetate and sodium hydroxide in the ethanol/water medium under microwave irradiations was investigated in this paper. The effects of reaction conditions such as the reaction time, the reaction temperature, and the amounts of sodium hydroxide and sodium monochloroacetate on the degree substitution (DS) of carboxymethylated hemicelluloses were discussed. The structures of hemicelluloses before and after the chemical modification were analyzed by13C nuclear magnetic resonance (NMR) spectra. Gel permeation chromatography (GPC) was used to characterize the carboxymethylated hemicelluloses. During the chemical modification, it was found that the remarkable degradation of hemicelluloses occurred under microwave irradiations.

Efficacy of xylanase purified from Aspergillus niger DFR-5 alone and in combination with pectinase and cellulase to improve yield and clarity of pineapple juice

Pineapple is one of the fruits having xylan rich hemicellulose content more than pectin. Therefore, the efficacy of absolutely purified xylanase from A. niger DFR-5 alone and in combination with pectinase and cellulase on juice yield and clarity was studied. Xylanase provided maximum yield (71.3%) and clarity (64.7%) of juice in comparison to control responses (61.8% yield and 57.8% clarity). When used together, a synergistic effect of xylanase, pectinase and cellulase on process responses was observed indicating the necessity of a cock-tail of hydrolytic enzymes for complete cell wall degradation. Overall, an increase in juice yield by 52.9% was observed. The process was numerically optimized with the constraint of 'minimum' pectinase and cellulase and 'maximum' xylanase and incubation time for 'maximum' juice yield and clarity. The closeness of observed response (90.2% yield and 80.9% clarity) to the predicted one (89.6% yield and 80.3% clarity) indicated the validity of developed model.

Homogeneous Esterification of Xylan-Rich Hemicelluloses with Maleic Anhydride in Ionic Liquid

Generation of bioenergy, new functional polymers, or chemicals and biomaterials from hemicelluloses are important uses for biomass. In this paper, a novel functional biopolymer with carbon-carbon double bond and carboxyl groups was prepared by a homogeneous esterification of xylan-rich hemicelluloses (XH) with maleic anhydride in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid using LiOH as catalyst. The biopolymers with degrees of substitution (DS) between 0.095 and 0.75 were accessible in a completely homogeneous system by changing reaction temperature, reaction time, the dosage of catalyst, and the molar ratio of maleic anhydride to anhydroxylose unit in XH. Results obtained from FT-IR and (13)C NMR spectroscopies confirmed the structure of hemicellulosic derivatives with carbon-carbon double bond and carboxyl groups, implying an efficient method to prepare a novel and important functional biopolymer for biomaterials.