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1.
Carbohydr Polym ; 339: 122243, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38823912

ABSTRACT

Pilling is a form of textile mechanical damage, forming fibrous bobbles on the surface of garments, resulting in premature disposal of clothing by consumers. However, our understanding on how the structural properties of the cellulosic matrix compliment the three-dimensional shape of cotton pills remains limited. This knowledge gap has hindered the development of effective 'pillase' technologies over the past 20 years due to challenges in balancing depilling efficacy with fabric integrity preservation. Therefore, the main focus here was characterising the role of cellulose and the hemicellulose components in cotton textiles to elucidate subtle differences between the chemistry of pills and fibre regions involved in structural integrity. State-of-the-art bioimaging using carbohydrate binding modules, monoclonal antibodies, and Leica SP8 and a Nikon A1R confocal microscopes, revealed the biophysical structure of cotton pills for the first time. Identifying regions of increased crystalline cellulose in the base of anchor fibres and weaker amorphous cellulose at dislocations in their centres, enhancing our understanding of current enzyme specificity. Surprisingly, pills contained a 7-fold increase in the concentration of xyloglucan compared to the main textile. Therefore, xyloglucan offers a previously undescribed target for overcoming this benefit-to-risk paradigm, suggesting a role for xyloglucanase enzymes in future pillase systems.


Subject(s)
Cellulose , Cotton Fiber , Glucans , Xylans , Cellulose/chemistry , Cotton Fiber/analysis , Xylans/chemistry , Xylans/metabolism , Glucans/chemistry , Crystallization , Textiles , Polysaccharides/chemistry
2.
Carbohydr Polym ; 339: 122248, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38823916

ABSTRACT

Arabinoxylan is a major hemicellulose in the sugarcane plant cell wall with arabinose decorations that impose steric restrictions on the activity of xylanases against this substrate. Enzymatic removal of the decorations by arabinofuranosidases can allow a more efficient arabinoxylan degradation by xylanases. Here we produced and characterized a recombinant Bifidobacterium longum arabinofuranosidase from glycoside hydrolase family 43 (BlAbf43) and applied it, together with GH10 and GH11 xylanases, to produce xylooligosaccharides (XOS) from wheat arabinoxylan and alkali pretreated sugarcane bagasse. The enzyme synergistically enhanced XOS production by GH10 and GH11 xylanases, being particularly efficient in combination with the latter family of enzymes, with a degree of synergism of 1.7. We also demonstrated that the enzyme is capable of not only removing arabinose decorations from the arabinoxylan and from the non-reducing end of the oligomeric substrates, but also hydrolyzing the xylan backbone yielding mostly xylobiose and xylose in particular cases. Structural studies of BlAbf43 shed light on the molecular basis of the substrate recognition and allowed hypothesizing on the structural reasons of its multifunctionality.


Subject(s)
Bifidobacterium longum , Cellulose , Endo-1,4-beta Xylanases , Glucuronates , Glycoside Hydrolases , Oligosaccharides , Saccharum , Xylans , Oligosaccharides/chemistry , Oligosaccharides/metabolism , Glycoside Hydrolases/metabolism , Glycoside Hydrolases/chemistry , Glucuronates/metabolism , Glucuronates/chemistry , Endo-1,4-beta Xylanases/metabolism , Endo-1,4-beta Xylanases/chemistry , Xylans/metabolism , Xylans/chemistry , Saccharum/chemistry , Saccharum/metabolism , Cellulose/chemistry , Cellulose/metabolism , Bifidobacterium longum/enzymology , Bifidobacterium longum/metabolism , Hydrolysis , Substrate Specificity , Recombinant Proteins/metabolism , Recombinant Proteins/chemistry , Disaccharides
3.
Carbohydr Polym ; 339: 122261, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38823925

ABSTRACT

Understanding the distribution and accessibility of polymers within plant cell walls is crucial for addressing biomass recalcitrance in lignocellulosic materials. In this work, Imaging Fourier Transform Infrared (FTIR) and Raman spectroscopy, coupled with targeted chemical treatments, were employed to investigate cell wall polymer distribution in two bamboo species at both tissue and cell wall levels. Tissue-level Imaging FTIR revealed significant disparities in the distribution and chemical activity of cell wall polymers between the fibrous sheath and fibrous strand. At the cell wall level, Imaging Raman spectroscopy delineated a distinct difference between the secondary wall and intercellular layer, with the latter containing higher levels of lignin, hydroxycinnamic acid (HCA), and xylan, and lower cellulose. Mild acidified sodium chlorite treatment led to partial removal of lignin, HCA, and xylan from the intercellular layer, albeit to a lesser extent than alkaline treatment, indicating susceptibility of these polymers to chemical treatment. In contrast, lignin in the secondary wall exhibited limited reactivity to acidified sodium chlorite but was slightly removed by alkaline treatment, suggesting stable chemical properties with slight alkaline intolerance. These findings provide valuable insights into the inherent design mechanism of plant cells and their efficient utilization.


Subject(s)
Cell Wall , Cellulose , Coumaric Acids , Lignin , Cell Wall/chemistry , Lignin/chemistry , Coumaric Acids/chemistry , Cellulose/chemistry , Spectroscopy, Fourier Transform Infrared/methods , Xylans/chemistry , Spectrum Analysis, Raman/methods , Sasa/chemistry , Chlorides/chemistry , Polymers/chemistry
4.
Compr Rev Food Sci Food Saf ; 23(3): e13366, 2024 May.
Article in English | MEDLINE | ID: mdl-38775125

ABSTRACT

Wheat bran (WB) is a well-known and valuable source of dietary fiber. Arabinoxylan (AX) is the primary hemicellulose in WB and can be isolated and used as a functional component in various food products. Typically, AX is extracted from the whole WB using different processes after mechanical treatments. However, WB is composed of different layers, namely, the aleurone layer, pericarp, testa, and hyaline layer. The distribution, structure, and extractability of AX vary within these layers. Modern fractionation technologies, such as debranning and electrostatic separation, can separate the different layers of WB, making it possible to extract AX from each layer separately. Therefore, AX in WB shows potential for broader applications if it can be extracted from the different layers separately. In this review, the distribution and chemical structures of AX in WB layers are first discussed followed by extraction, physicochemical properties, and health benefits of isolated AX from WB. Additionally, the utilization of AX isolated from WB in foods, including cereal foods, packaging film, and the delivery of food ingredients, is reviewed. Future perspectives on challenges and opportunities in the research field of AX isolated from WB are highlighted.


Subject(s)
Dietary Fiber , Xylans , Xylans/chemistry , Dietary Fiber/analysis
5.
Carbohydr Polym ; 337: 122141, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38710568

ABSTRACT

Production of value-added compounds and sustainable materials from agro-industrial residues is essential for better waste management and building of circular economy. This includes valorization of hemicellulosic fraction of plant biomass, the second most abundant biopolymer from plant cell walls, aiming to produce prebiotic oligosaccharides, widely explored in food and feed industries. In this work, we conducted biochemical and biophysical characterization of a prokaryotic two-domain R. champanellensis xylanase from glycoside hydrolase (GH) family 30 (RcXyn30A), and evaluated its applicability for XOS production from glucuronoxylan in combination with two endo-xylanases from GH10 and GH11 families and a GH11 xylobiohydrolase. RcXyn30A liberates mainly long monoglucuronylated xylooligosaccharides and is inefficient in cleaving unbranched oligosaccharides. Crystallographic structure of RcXyn30A catalytic domain was solved and refined to 1.37 Å resolution. Structural analysis of the catalytic domain releveled that its high affinity for glucuronic acid substituted xylan is due to the coordination of the substrate decoration by several hydrogen bonds and ionic interactions in the subsite -2. Furthermore, the protein has a larger ß5-α5 loop as compared to other GH30 xylanases, which might be crucial for creating an additional aglycone subsite (+3) of the catalytic site. Finally, RcXyn30A activity is synergic to that of GH11 xylobiohydrolase.


Subject(s)
Endo-1,4-beta Xylanases , Gastrointestinal Microbiome , Glucuronates , Oligosaccharides , Xylosidases , Glucuronates/metabolism , Glucuronates/chemistry , Oligosaccharides/chemistry , Oligosaccharides/metabolism , Endo-1,4-beta Xylanases/metabolism , Endo-1,4-beta Xylanases/chemistry , Xylosidases/metabolism , Xylosidases/chemistry , Humans , Crystallography, X-Ray , Xylans/chemistry , Xylans/metabolism , Catalytic Domain , Models, Molecular , Substrate Specificity
6.
Int J Biol Macromol ; 270(Pt 2): 132522, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38768922

ABSTRACT

The current study goal was to improve mucoadhesive potential and ocular pharmacokinetics of nanoparticles of thiolated xyloglucan (TXGN) containing moxifloxacin (MXF). Thiolation of xyloglucan (XGN) was achieved with esterification with 3-mercaptopropionic acid. TXGN was characterized by NMR and FTIR analysis. The nanoparticles of TXGN were prepared using ionic-gelation method and evaluate the antibacterial properties. TXGN and nanoparticles were determined to possess 0.06 and 0.08 mmol of thiol groups/mg of polymer by Ellman's method. The ex-vivo bioadhesion time of TXGN and nanoparticles was higher than XGN in a comparative assessment of their mucoadhesive properties. The creation of a disulfide link between mucus and TXGN is responsible for the enhanced mucoadhesive properties of TXGN (1-fold) and nanoparticles (2-fold) over XGN. Improved MXF penetration in nanoparticulate formulation (80 %) based on TXGN was demonstrated in an ex-vivo permeation research utilizing rabbit cornea. Dissolution study showed 95 % release of MXF from nanoparticles. SEM images of nanoparticles showed spherical shape and cell viability assay showed nontoxic behavior when tested on RPE cell line. Antibacterial analysis revealed a zone of inhibition of 31.5 ± 0.5 mm for MXF, while NXM3 exhibited an expanded zone of 35.5 ± 0.4 mm (p < 0.001). In conclusion, thiolation of XGN improves its bioadhesion, permeation, ocular-retention and pharmacokinetics of MXF.


Subject(s)
Glucans , Moxifloxacin , Nanoparticles , Xylans , Xylans/chemistry , Glucans/chemistry , Moxifloxacin/chemistry , Moxifloxacin/pharmacokinetics , Moxifloxacin/pharmacology , Animals , Rabbits , Nanoparticles/chemistry , Drug Carriers/chemistry , Anti-Bacterial Agents/pharmacokinetics , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/administration & dosage , Sulfhydryl Compounds/chemistry , Cornea/metabolism , Cornea/drug effects , Humans , Drug Delivery Systems , Permeability , Cell Line , Administration, Ophthalmic , Adhesiveness , Adhesives/chemistry
7.
Int J Biol Macromol ; 270(Pt 1): 131856, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38693000

ABSTRACT

Biomacromolecules derived from natural sources offer superior biocompatibility, biodegradability, and water-holding capacity, which make them promising scaffolds for tissue engineering. Psyllium seed has gained attention in biomedical applications recently due to its gel-forming ability, which is provided by its polysaccharide-rich content consisting mostly of arabinoxylan. This study focuses on the extraction and gelation of Psyllium seed hydrocolloid (PSH) in a single-step water-based protocol, and scaffold fabrication using freeze-drying method. After characterization of the scaffold, including morphological, mechanical, swelling, and protein adsorption analyses, 3D cell culture studies were done using NIH-3 T3 fibroblast cells on PSH scaffold, and cell viability was assessed using Live/Dead and Alamar Blue assays. Starting from day 1, high cell viability was obtained, and it reached 90 % at the end of 15-day culture period. Cellular morphology on PSH scaffold was monitored via SEM analysis; cellular aggregates then spheroid formation were observed throughout the study. Collagen Type-I and F-actin expressions were followed by immunostaining revealing a 9- and 10-fold increase during long-term culture. Overall, a single-step and non-toxic protocol was developed for extraction and gelation of PSH. Obtained results unveiled that PSH scaffold provided a favorable 3D microenvironment for cells, holding promise for further tissue engineering applications.


Subject(s)
Colloids , Psyllium , Seeds , Tissue Engineering , Tissue Scaffolds , Xylans , Psyllium/chemistry , Xylans/chemistry , Xylans/pharmacology , Tissue Engineering/methods , Animals , Seeds/chemistry , Mice , Colloids/chemistry , Tissue Scaffolds/chemistry , NIH 3T3 Cells , Cell Survival/drug effects , Water/chemistry
8.
Int J Biol Macromol ; 270(Pt 2): 132211, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38723833

ABSTRACT

Prebiotics are non-digestible compounds that promote intestinal microbiota growth and/or activity. Xylooligosaccharides (XOS) are new prebiotics derived from the hemicellulose fraction of lignocellulosic materials. Challenges in using those materials as sources for prebiotic compounds lie in the hemicellulose extraction efficiency and the safety of those ingredients. In this sense, this work aims to optimize hemicellulose extraction and XOS production through direct enzymatic hydrolysis of alkali pre-treated wheat straw without undesired byproducts. By increasing the temperature of the enzymatic step from 40 °C to 65 °C we achieved an improvement in the extraction yield from 55 % to 80 %. Products with different degrees of polymerization were also noticed: while XOS ≤ X6 where the main products at 40 °C, a mixture of long arabinoxylan derived polymers (ADPo) and XOS ≤ X6 was obtained at 65 °C, irrespective of the extraction yield. Thus, a modulatory effect of temperature on the product profile is suggested here. Among the XOS ≤ X6 produced, X2-X3 were the main products, and X4 was the minor one. At the end of the hydrolysis, 146.7 mg XOS per gram of pre-treated wheat straw were obtained.


Subject(s)
Endo-1,4-beta Xylanases , Oligosaccharides , Polysaccharides , Temperature , Triticum , Triticum/chemistry , Hydrolysis , Polysaccharides/chemistry , Endo-1,4-beta Xylanases/metabolism , Oligosaccharides/chemistry , Glucuronates/chemistry , Xylans/chemistry , Xylans/metabolism
9.
Carbohydr Polym ; 337: 122112, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38710545

ABSTRACT

The growing concerns on environmental pollution and sustainability have raised the interest on the development of functional biobased materials for different applications, including food packaging, as an alternative to the fossil resources-based counterparts, currently available in the market. In this work, functional wood inspired biopolymeric nanocomposite films were prepared by solvent casting of suspensions containing commercial beechwood xylans, cellulose nanofibers (CNF) and lignosulfonates (magnesium or sodium), in a proportion of 2:5:3 wt%, respectively. All films presented good homogeneity, translucency, and thermal stability up to 153 °C. The incorporation of CNF into the xylan/lignosulfonates matrix provided good mechanical properties to the films (Young's modulus between 1.08 and 3.79 GPa and tensile strength between 12.75 and 14.02 MPa). The presence of lignosulfonates imparted the films with antioxidant capacity (DPPH radical scavenging activity from 71.6 to 82.4 %) and UV barrier properties (transmittance ≤19.1 % (200-400 nm)). Moreover, the films obtained are able to successfully delay the browning of packaged fruit stored over 7 days at 4 °C. Overall, the obtained results show the potential of using low-cost and eco-friendly resources for the development of sustainable active food packaging materials.


Subject(s)
Cellulose , Food Packaging , Lignin , Lignin/analogs & derivatives , Nanocomposites , Nanofibers , Tensile Strength , Wood , Xylans , Food Packaging/methods , Lignin/chemistry , Nanocomposites/chemistry , Cellulose/chemistry , Cellulose/analogs & derivatives , Wood/chemistry , Nanofibers/chemistry , Xylans/chemistry , Antioxidants/chemistry , Fruit/chemistry
10.
Carbohydr Polym ; 337: 122137, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38710567

ABSTRACT

Xylans' unique properties make it attractive for a variety of industries, including paper, food, and biochemical production. While for some applications the preservation of its natural structure is crucial, for others the degradation into monosaccharides is essential. For the complete breakdown, the use of several enzymes is required, due to its structural complexity. In fact, the specificity of enzymatically-catalyzed reactions is guided by the surface, limiting or regulating accessibility and serving structurally encoded input guiding the actions of the enzymes. Here, we investigate enzymes at surfaces rich in xylan using surface plasmon resonance spectroscopy. The influence of diffusion and changes in substrate morphology is studied via enzyme surface kinetics simulations, yielding reaction rates and constants. We propose kinetic models, which can be applied to the degradation of multilayer biopolymer films. The most advanced model was verified by its successful application to the degradation of a thin film of polyhydroxybutyrate treated with a polyhydroxybutyrate-depolymerase. The herein derived models can be employed to quantify the degradation kinetics of various enzymes on biopolymers in heterogeneous environments, often prevalent in industrial processes. The identification of key factors influencing reaction rates such as inhibition will contribute to the quantification of intricate dynamics in complex systems.


Subject(s)
Surface Plasmon Resonance , Xylans , Xylans/chemistry , Xylans/metabolism , Surface Plasmon Resonance/methods , Kinetics , Surface Properties
11.
Carbohydr Polym ; 336: 122123, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-38670754

ABSTRACT

Arabinoglucuronoxylans obtained from the exudate of Cercidium praecox (Brea gum) were subjected to an amidation reaction to modulate their flow behavior to obtain a product with similar behavior to gum Arabic. The amidation reaction of the uronic acids present in this exudate was studied using the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) system with the aim of maximizing product yield and minimizing by-product. An analysis of the significant factors involved in the reaction was carried out and a response surface methodology was conducted to optimize the stoichiometry of the reagents used. It was possible to obtain models for predicting the degree of amidation (DA) of arabinoglucuronoxylans and the formation of by-products. The formation of a secondary product derived from the amino acid ß-alanine which has not been reported previously in the reaction with polysaccharides, was described. The flow behavior of an amidated product (DA = 52 %) was determined, showing a pseudoplastic behavior and a decreased Newtonian viscosity (η0 = 36.2 Pa s) at the lowest shear rate range with respect to native product solution (η0 = 115 Pa s). Amidated arabinoglucuronoxylans had a flow behavior more similar to that of gum Arabic.


Subject(s)
Xylans , Viscosity , Xylans/chemistry , Rheology , Uronic Acids/chemistry
12.
Carbohydr Polym ; 336: 122102, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-38670773

ABSTRACT

Skin wounds are susceptible to infection, leading to severe inflammatory reactions that can progress to chronic wounds, ultimately causing significant physical and mental distress to the patient. In this study, we propose an injectable composite hydrogel achieved through one-pot gelation of oxidized xyloglucan (OXG), cationic polyamide ε-poly-l-lysine (EPL), and surface amino-rich silicon nanoparticles (SiNPs). OXG exhibits commendable anti-inflammatory properties and provides crosslinking sites. SiNPs serve as mechanically reinforced crosslinkers, facilitating the construction of a dynamic Schiff base network. SiNPs significantly reduced the gelation time to 3 s and tripled the storage modulus of the hydrogels. Additionally, the combination of EPL and SiNPs demonstrated synergistic antimicrobial activity against both S. aureus and E. coli. Notably, the hydrogel effectively halted liver bleeding within 30 s. The hydrogel demonstrated outstanding shear-thinning and self-healing properties, crucial considerations for the design of injectable hydrogels. Furthermore, its efficacy was evaluated as a wound dressing in a mouse model with S. aureus infection. The results indicated that, compared to commercial products, the hydrogel exhibited a shorter wound healing time, decreased inflammation, thinner epithelium, increased hair follicles, enhanced neovascularization, and more substantial collagen deposition. These findings strongly suggest the promising potential of the proposed hydrogel as an effective wound dressing for the treatment of infected wounds.


Subject(s)
Anti-Bacterial Agents , Escherichia coli , Glucans , Hydrogels , Nanoparticles , Polylysine , Staphylococcus aureus , Wound Healing , Xylans , Glucans/chemistry , Glucans/pharmacology , Animals , Wound Healing/drug effects , Xylans/chemistry , Xylans/pharmacology , Hydrogels/chemistry , Hydrogels/pharmacology , Polylysine/chemistry , Polylysine/pharmacology , Mice , Nanoparticles/chemistry , Escherichia coli/drug effects , Staphylococcus aureus/drug effects , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/administration & dosage , Staphylococcal Infections/drug therapy , Cross-Linking Reagents/chemistry , Wound Infection/drug therapy , Male
13.
J Agric Food Chem ; 72(18): 10206-10217, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38597965

ABSTRACT

Bamboo is a promising biomass resource. However, the complex multilayered structure and chemical composition of bamboo cell walls create a unique anti-depolymerization barrier, which increases the difficulty of separation and utilization of bamboo. In this study, the relationship between the connections of lignin-carbohydrate complexes (LCCs) within bamboo cell walls and their multilayered structural compositions was investigated. The chemical composition, structural properties, dissolution processes, and migration mechanisms of LCCs were analyzed. Alkali-stabilized LCC bonds were found to be predominantly characterized by phenyl glycoside (PhGlc) bonds along with numerous p-coumaric acid (PCA) linkage structures. As demonstrated by the NMR and CLSM results, the dissolution of the LCC during the alkaline pretreatment process was observed to migrate from the inner secondary wall (S-layer) of the bamboo fiber cell walls to the cell corner middle lamella (CCML) and compound middle lamella (CML), ultimately leading to its release from the bamboo. Furthermore, the presence of H-type lignin-FA-arabinoxylan linkage structures within the bamboo LCC was identified with their primary dissolution observed in the S-layer of the bamboo fiber cell walls. The study results provided a clear target for breaking down the anti-depolymerization barrier in bamboo, signifying a major advancement in achieving the comprehensive separation of bamboo components.


Subject(s)
Carbohydrates , Cell Wall , Lignin , Lignin/chemistry , Cell Wall/chemistry , Carbohydrates/chemistry , Alkalies/chemistry , Sasa/chemistry , Solubility , Poaceae/chemistry , Xylans/chemistry , Magnetic Resonance Spectroscopy
14.
Protein Expr Purif ; 219: 106478, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38570105

ABSTRACT

Xylanases are the main enzymes to hydrolyze xylan, the major hemicellulose found in lignocellulose. Xylanases also have a wide range of industrial applications. Therefore, the discovery of new xylanases has the potential to enhance efficiency and sustainability in many industries. Here, we report a xylanase with thermophilic character and superior biochemical properties for industrial use. The new xylanase is discovered in Anoxybacillus ayderensis as an intracellular xylanase (AAyXYN329) and recombinantly produced. While AAyXYN329 shows significant activity over a wide pH and temperature range, optimum activity conditions were determined as pH 6.5 and 65 °C. The half-life of the enzyme was calculated as 72 h at 65 °C. The enzyme did not lose activity between pH 6.0-9.0 at +4 °C for 75 days. Km, kcat and kcat/Km values of AAyXYN329 were calculated as 4.09824 ± 0.2245 µg/µL, 96.75 1/sec, and 23.61/L/g.s -1, respectively. In conclusion, the xylanase of A. ayderensis has an excellent potential to be utilized in many industrial processes.


Subject(s)
Anoxybacillus , Bacterial Proteins , Endo-1,4-beta Xylanases , Enzyme Stability , Recombinant Proteins , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Recombinant Proteins/isolation & purification , Anoxybacillus/enzymology , Anoxybacillus/genetics , Endo-1,4-beta Xylanases/genetics , Endo-1,4-beta Xylanases/chemistry , Endo-1,4-beta Xylanases/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Hydrogen-Ion Concentration , Cloning, Molecular , Temperature , Escherichia coli/genetics , Xylans/metabolism , Xylans/chemistry , Substrate Specificity , Kinetics
15.
Protein Expr Purif ; 219: 106482, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38583789

ABSTRACT

GH11 enzyme is known to be specific and efficient for the hydrolysis of xylan. It has been isolated from many microorganisms, and its enzymatic characteristics and thermostability vary between species. In this study, a GH11 enzyme PphXyn11 from a novel xylan-degrading strain of Paenibacillus physcomitrellae XB was characterized, and five mutants were constructed to try to improve the enzyme's thermostability. The results showed that PphXyn11 was an acidophilic endo-ß-1,4-xylanase with the optimal reaction pH of 3.0-4.0, and it could deconstruct different kinds of xylan substrates efficiently, such as beechwood xylan, wheat arabinoxylan and xylo-oligosaccharides, to produce xylobiose and xylotriose as the main products at the optimal reaction temperature of 40 °C. Improvement of the thermal stability of PphXyn11 using site-directed mutagenesis revealed that three mutants, W33C/N47C, S127C/N174C and S49E, designed by adding the disulfide bonds at the N-terminal, C-terminal and increasing the charged residues on the surface of PphXyn11 respectively, could increase the enzymatic activity and thermal stablility significantly and make the optimal reaction temperature reach 50 °C. Molecular dynamics simulations as well as computed the numbers of salt bridges and hydrogen bonds indicated that the protein structures of these three mutants were more stable than the wild type, which provided theoretical support for their improved thermal stability. Certainly, further research is necessary to improve the enzymatic characteristics of PphXyn11 to achieve the bioconversion of hemicellulosic biomass on an applicable scale.


Subject(s)
Endo-1,4-beta Xylanases , Enzyme Stability , Paenibacillus , Paenibacillus/enzymology , Paenibacillus/genetics , Endo-1,4-beta Xylanases/genetics , Endo-1,4-beta Xylanases/chemistry , Endo-1,4-beta Xylanases/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Xylans/metabolism , Xylans/chemistry , Hydrogen-Ion Concentration , Mutagenesis, Site-Directed , Recombinant Proteins/genetics , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Temperature , Substrate Specificity
16.
Int J Biol Macromol ; 269(Pt 2): 131771, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38688792

ABSTRACT

Xyloglucan (XG), as a natural biopolymer, possesses a sound biocompatibility and an impressive biodegradability, which are usually featured with abundant hydroxyl groups available for the bioconjugation with a bioactive moiety, suggesting a promising or unique value possibly applied in the field of biomedicine. In this study, XG was extracted from Tamarind seeds and subjected to four regioselective oxidation methods to introduce carboxyl groups onto the XG molecules for a bioconjugation with collagen. Galactose oxidase and reducing end aldehyde group oxidation mainly resulted in a low carboxylate content at ∼0.34 mmol/g, whereas the primary and secondary hydroxyl group oxidations would lead to a high carboxyl content at ∼0.84 mmol/g. The number-average molar mass (Mn) and weight-average molar mass (Mw) of XG were 8.8 × 105 g/mol and 1.1 × 106 g/mol, respectively. The oxidized XGs were then subjected to a further biofunctionalization with the collagen through EDC/NHS coupling, which exhibited a degree of conjugation rate, ranged from 50 % to 72 %. The collagen-conjugated at the C6 position of XGs exhibited the highest cell viability recorded at 168 % in promoting cell growth and proliferation after 72 h of culture, surpassing that of pure collagen recorded at 138 %, which may indeed suggest a promising value in a biomedical application.


Subject(s)
Collagen , Glucans , Oxidation-Reduction , Xylans , Xylans/chemistry , Glucans/chemistry , Collagen/chemistry , Carboxylic Acids/chemistry , Cell Survival/drug effects , Tamarindus/chemistry , Animals , Cell Proliferation/drug effects , Humans
17.
Carbohydr Res ; 538: 109080, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38513464

ABSTRACT

Polysaccharides have attracted immense attention as the largest source of bioactive compounds. Its bioavailability and bioactivity can be improved by utilizing degradation enzymes to reduce their molecular weight and viscosity. In this study, a 654 bp gene encoding xylanase was screened from the genome of Bacillus altitudinis JYY-02 and overexpressed in Escherichia coli Rosetta (DE3). The recombinant xylanase with a molecular weight of 27.98 kDa was purified (11.7-fold) using Ni-NTA affinity chromatography, with a 43.6% final yield. Through molecular docking, Glu, Arg, Tyr, and Trp were found to be the main amino acids involved in the interaction between xylanase and xylobiose. The effects of pH, temperature, metal ions, and substrates on xylanase activity were determined, and the results showed that the highest catalytic activity was displayed at pH 6.5, 50 °C temperature, with Cu2+ as an activator and xylan as the substrate. The Km (substrate concentration that yields a half-maximal velocity) and Vmax (maximum velocity) of recombinant xylanase were 6.876 mg/mL and 10984.183 µmol/mg∙pr/min, respectively. The recombinant xylanase was thermostable, with 85% and 39% of the enzymatic activity retained after 1 h at 60 °C and 1 h at 90 °C, respectively. The recombinant xylanase demonstrated a significant clarifying effect on fruit juices.


Subject(s)
Bacillus , Endo-1,4-beta Xylanases , Endo-1,4-beta Xylanases/metabolism , Molecular Docking Simulation , Polysaccharides , Bacillus/genetics , Temperature , Xylans/chemistry , Hydrogen-Ion Concentration , Enzyme Stability , Cloning, Molecular , Substrate Specificity
18.
J Mater Sci Mater Med ; 35(1): 20, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38526669

ABSTRACT

Xyloglucan is a rigid polysaccharide that belongs to the carbohydrate family. This hemicellulose compound has been widely used in biomedical research because of its pseudoplastic, mucoadhesive, mucomimetic, and biocompatibility properties. Xyloglucan is a polyose with no amino groups in its structure, which also limits its range of applications. It is still unknown whether grafting hydrophilic monomers onto xyloglucan can produce derivatives that overcome these shortcomings. This work aimed to prepare the first copolymers in which N-hydroxyethyl acrylamide is grafted onto tamarind xyloglucan by free-radical polymerization. The biocompatibility of these structures in vitro was evaluated using human dermal fibroblasts. Gamma radiation-induced graft polymerization was employed as an initiator by varying the radiation dose from 5-25 kGy. The structure of the graft copolymer, Xy-g-poly(N-hydroxyethyl acrylamide), was verified by thermal analysis, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The findings indicate that the degree of grafting and the cytotoxicity/viability of the xyloglucan-based copolymer were independent of dose. Notably, the grafted galactoxyloglucan exhibited efficient support for human dermal fibroblasts, showing heightened proliferative capacity and superior migration capabilities compared to the unmodified polymer. This copolymer might have the potential to be used in skin tissue engineering.


Subject(s)
Acrylamide , Glucans , Polymers , Humans , Acrylamide/chemistry , Polymerization , Polymers/chemistry , Xylans/chemistry , Spectroscopy, Fourier Transform Infrared
19.
Carbohydr Polym ; 334: 122029, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38553229

ABSTRACT

To investigate the incubation conditions encountered by enzymes in cereal-based product transformation processes, this study aims to provide comprehensive information on the effect of low (18 %) to high (72 %) solid loading on the behavior of bacterial and fungal xylanases towards wheat grain fractions, i.e. white flour, ground whole grain and bran. Both enzymes are effective from 30 % water content. A water content of 50 % appears as the threshold for optimal arabinoxylan solubilisation. The specificity of enzymes was influenced by low hydration conditions, particularly in wheat bran, which contains arabinoxylan with diverse structures. Especially the bacterial xylanase became more tolerant to arabinose substitution as the water content decreased. Time Domain-NMR measurements revealed four water mobility domains in all the fractions. The water populations corresponding to 7.5 nm to 15 nm pores were found to be the most restrictive for enzyme activity. These results define the water content limits for the optimal xylanase action in cereal products.


Subject(s)
Endo-1,4-beta Xylanases , Xylans , Endo-1,4-beta Xylanases/chemistry , Xylans/chemistry , Dietary Fiber/analysis , Flour , Magnetic Resonance Spectroscopy , Edible Grain/chemistry , Water
20.
Int J Biol Macromol ; 264(Pt 1): 130550, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38432267

ABSTRACT

A novel endo-1,4-ß-xylanase-encoding gene was identified in Alicyclobacillus mali FL18 and the recombinant protein, named AmXyn, was purified and biochemically characterized. The monomeric enzyme worked optimally at pH 6.6 and 80 °C on beechwood xylan with a specific activity of 440.00 ± 0.02 U/mg and a good catalytic efficiency (kcat/KM = 91.89 s-1mLmg-1). In addition, the enzyme did not display any activity on cellulose, suggesting a possible application in paper biobleaching processes. To develop an enzymatic mixture for xylan degradation, the association between AmXyn and the previously characterized ß-xylosidase AmßXyl, deriving from the same microorganism, was assessed. The two enzymes had similar temperature and pH optima and showed the highest degree of synergy when AmXyn and AmßXyl were added sequentially to beechwood xylan, making this mixture cost-competitive and suitable for industrial use. Therefore, this enzymatic cocktail was also employed for the hydrolysis of wheat bran residue. TLC and HPAEC-PAD analyses revealed a high conversion rate to xylose (91.56 %), placing AmXyn and AmßXyl among the most promising biocatalysts for the saccharification of agricultural waste.


Subject(s)
Alicyclobacillus , Endo-1,4-beta Xylanases , Polysaccharides , Xylans , Xylosidases , Endo-1,4-beta Xylanases/chemistry , Xylans/chemistry , Hydrolysis , Hydrogen-Ion Concentration
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