Hofmeister effect driven dynamic-bond cross-linked dialdehyde xylan hydrogels with rapid response and robust mechanical properties for expanding stent.

The biomedical field urgently needs for programmable stent materials with nontoxic, autonomous self-healing, injectability, and suitable mechanical strength, especially self-expanding characteristics. However, such materials are still lacking. Herein, based on gelatin and dialdehyde-functionalized xylan, we synthesized 3D-printable, autonomous, self-healing, and mechanically robust hydrogels with a reversible Schiff base crosslink network. The hydrogels exhibited excellent mechanical properties and automatic healing properties at room temperature. The solid mechanical properties originate from the Schiff base, hydrogen bonding interactions, and xylan nanoparticle reinforcement of the polymer networks. As a proof of concept, the Hofmeister effect enabled the hydrogel to contract in highly concentrated salt solutions. In contrast, the same hydrogel expanded and relaxed in dilute salt solutions (quick response within 10 s), showing ionic stimulus-response and excellent shape memory characteristics, which demonstrated that the prepared hydrogel could be used as self-expanding artificial vascular stents. In particular, good biocompatibility was confirmed by cytotoxicity and compatibility tests, and ex vivo arterial experiments further indicated the feasibility of these artificial vascular scaffolds (the expansion force reached 1.51 N). Combined with its ionic stimuli-responsive shape memory ability, the strong mechanical, self-healing, 3D-printable, and biocompatibility properties make this hydrogel a promising material for artificial stents in various biomedical applications.

Efficient conversion of xylan to l-arabinose by multi-enzymatic cascade reaction including d-xylulose 4-epimerase as a new stereoselectivity-exchange enzyme.

l-Arabinose has been produced by hydrolyzing arabinan, a component of hemicellulose. However, l-arabinose has limitations in industrial applications owing to its relatively high cost. Here, d-xylulose 4-epimerase as a new-type enzyme was developed from d-tagaturonate 3-epimerase from Thermotoga petrophila using structure-guided enzyme engineering. d-Xylulose 4-epimerase, which epimerized d-xylulose to l-ribulose, d-xylulokinase and sugar phosphatase, which overcame the equilibrium of d-xylose isomerase, were included to establish a new efficient conversion pathway from d-xylose to l-arabinose. l-Arabinose at 34 g/L was produced from 100 g/L xylan in 45 h by multi-enzymatic cascade reaction using xylanase and enzymes involved in the established conversion pathway. As l-ribulokinase was used instead of d-xylulokinase in the established conversion pathway, an efficient reverse-directed conversion pathway from l-arabinose to d-xylose and the production of d-xylose from arabinan using arabinanase and enzymes involved in the proposed pathway are proposed.

Xylan acetate ester ameliorates ulcerative colitis through intestinal barrier repair and inflammation inhibition via regulation of macrophage M1 polarization.

Ulcerative colitis (UC) is a chronic inflammatory disease resulting from abnormal immune response to gut microflora translocating through damaged intestinal barrier. Xylan acetate ester (XylA) can increase colon short-chain fatty acids (SCFAs) levels and alleviate kidney disease by inhibiting inflammation through the G protein-coupled receptor pathway. Here, we synthesized and purified XylA, and then the effects and mechanisms of XylA on dextran sodium sulfate-induced UC in mice were investigated. The results showed that in mice, similar to the positive drug 5-aminosalicylic acid, oral administration of XylA significantly alleviated all UC symptoms, including weight loss, diarrhea, and hematochezia. Further mechanism studies revealed that XylA could repair the damaged colon structure and intestinal barrier function by increasing the expression of tight junction protein zonula occludens 1 and occludin, thus reducing LPS penetration. Moreover, XylA could also restrain intestinal inflammation via inhibiting LPS-TLR4 pathway, downregulating M1 macrophage polarization, and reducing proinflammatory cytokines expression, and in vitro cell experiments showed that these effects may be mediated by XylA derived SCFAs, particularly acetates, propionates and butyrates. All these results suggested that XylA may be a potential improving agent for UC treatment, and natural polysaccharides may represent a novel avenue for drug development of UC.

Biomass based nanofiber membrane composite with xylan derived carbon dots for fluorescence detection nitrite in food real samples.

In our latest research endeavor, we are proud to present an innovative approach to the synthesis of carbon dots (CDs) derived from the biomass xylan, which we have termed P-CDs. These P-CDs are meticulously integrated with a state-of-the-art biomass nanofiber membrane composed of polycaprolactone (PCL) and polylactic acid (PLA), resulting in the creation of a novel solid-state fluorescent sensor, designated as NFP-CDs. This cutting-edge sensor has been meticulously engineered for the highly sensitive and specific detection of nitrite ions (NO2-), a critical parameter in various fields. The NFP-CDs sensor stands out for its user-friendly design, cost-effective production, and portable nature, making it an ideal choice for rapid and visible nitrite ion detection. It exhibits an extraordinary response time of less than 1 s, which is a testament to its high sensitivity. Furthermore, the sensor demonstrates exceptional selectivity and specificity, with a remarkably low detection threshold of 0.36 µM. This is achieved through a sophisticated dual detection mechanism that synergistically combines colorimetric and spectral analyses, ensuring accurate and reliable results. In addition to its impressive technical specifications, the NFP-CDs sensor has been rigorously tested and validated for its efficacy in detecting nitrite ions in real-world samples. These samples include a diverse range of food products such as rock sugar, preserved mustard, kimchi, and canned fish. The sensor has demonstrated a remarkable recovery rate, which varies from 99 % to 106 %, highlighting its potential for practical application in nitrite ion detection. This research not only offers a robust and effective strategy for the detection of nitrite ions but also carries profound implications for enhancing food safety and bolstering environmental monitoring efforts. The development of the NFP-CDs sensor represents a significant step forward in the field of sensor technology, providing a powerful tool for the detection of nitrite ions and contributing to the broader goals of public health and environmental stewardship.

Slow-release antimicrobial preservation composite coating based on bamboo-derived xylan-A new way to preserve blueberry freshness.

In recent years, the biocompatibility and environmental friendliness of xylan-based materials have demonstrated great potential in the field of food packaging and coatings. In this study, the cationized xylan based composite coating (CXC) was developed using a hybrid system of cationic-modified bamboo xylan (CMX) and sodium alginate (SA) combined with thyme oil microcapsules (TM). The optimized CXC-B was composed of 1.27 % TM, 2.42 % CMX (CMX: SA = 3:2), and 96.31 % distilled water. When applied to the surface of a blueberry, the CXC-B treatment extended the ambient storage time of the fruit to 10 days while substantially reducing its morbidity (P < 0.05) and protecting its texture, flavor, and nutritional integrity. The resulting composite coating provides a promising solution to the problem of blueberry perishability during ambient storage.

Surface-enhanced Raman spectroscopy for the characterization of xylanases enzyme.

Xylanases are essential hydrolytic enzymes which break down the plant cell wall polysaccharide, xylan composed of D-xylose monomers. Surface-enhanced Raman Spectroscopy (SERS) was utilized for the characterization of interaction of xylanases with xylan at varying concentrations. The study focuses on the application of SERS for the characterization of enzymatic activity of xylanases causing hydrolysis of Xylan substrate with increase in its concentration which is substrate for this enzyme in the range of 0.2% to 1.0%. SERS differentiating features are identified which can be associated with xylanases treated with different concentrations of xylan. SERS measurements were performed using silver nanoparticles as SERS substrate to amplify Raman signal intensity for the characterization of xylan treated with xylanases. Principal Component Analysis (PCA) and Partial Least Square Discriminant Analysis (PLS-DA) were applied to analyze the spectral data to analyze differentiation between the SERS spectra of different samples. Mean SERS spectra revealed significant differences in spectral features particularly related to carbohydrate skeletal mode and O-C-O and C-C-C ring deformations. PCA scatter plot effectively differentiates data sets, demonstrating SERS ability to distinguish treated xylanases samples and the PC-loadings plot highlights the variables responsible for differentiation. PLS-DA was employed as a quantitative classification model for treated xylanase enzymes with increasing concentrations of xylan. The values of sensitivity, specificity, and accuracy were found to be 0.98%, 0.99%, and 100% respectively. Moreover, the AUC value was found to be 0.9947 which signifies the excellent performance of PLS-DA model. SERS combined with multivariate techniques, effectively characterized and differentiated xylanase samples as a result of interaction with different concentrations of the Xylan substrate. The identified SERS features can help to characterize xylanases treated with various concentrations of xylan with promising applications in the bio-processing and biotechnology industries.

Polyol-assisted ternary deep eutectic solvent protective lignocellulose pretreatment for high-efficiency xylan utilization and ethanol production.

The traditional lignocellulose pretreatment by deep eutectic solvent (DES) was usually conducted under higher acidic, alkaline and high temperature conditions, which leads to the severe degradation of xylan, decreasing the subsequent reducing sugar concentration by enzymatic hydrolysis and further ethanol fermentation. It is essential to develop an effective DES that selectively removes lignin while preventing excessive xylan degradation during lignocellulose pretreatment. An effective ethylene glycol-assisted ternary DES was designed to treat corn straw (CS) at 100 °C for 6 h. 65.51 % lignin removal was achieved, over 93.46 % cellulose and 50.22 % xylan were retained in pretreated CS with excellent enzymatic digestibility (glucan conversion of 77.05 % and xylan conversion of 71.72 %), total sugar conversion could reach 75.93 %, implying the unique capacity to selectively remove lignin while preserving carbohydrate components. Furthermore, the universality of the selective removal of lignin and effective retention of xylan by ternary DES has been successfully proven by other polyols. The enzymatic hydrolysate of ternary DES-pretreated CS fermented over our genetically engineered yeast strain SFA1OE gave a high ethanol yield of 0.488 g/g total reducing sugar, demonstrating the effectiveness of the polyol-assisted ternary DES pretreatment in achieving high-efficiency cellulosic ethanol production.

Synergistic xylan decomposition by a reducing-end xylose-releasing exo-oligoxylanase with other xylanolytic enzymes derived from Paenibacillus xylaniclasticus strain TW1.

Paenibacillus xylaniclasticus strain TW1 is a promising tool for decomposing xylan-containing lignocellulosic biomass, since this strain possesses various genes encoding cellulolytic/hemicellulolytic enzymes. In this study, PxRex8A from the TW1 strain was found to be a reducing-end xylose-releasing exo-oligoxylanase of glycoside hydrolase family 8, which cleaves xylose from xylooligosacchrides of corn core xylan. In synergistic assay, the efficient decomposition of oat spelt xylan (OSX) and beech wood xylan was exemplified in the combination of endo ß-1,4-xylanase (PxXyn11A) and PxRex8A from the TW1 strain in a molar ratio of 4:1. Furthermore, it was found that the addition of ß-d-xylosidase/α-l-arabinofuranosidase (PxXyl43A) from this strain with PxXyn11A and PxRex8A achieved twice the amount of reducing sugars (1.1 mg/mL) against OSX after 24 hours compared to PxXyn11A alone (0.5 mg/mL). These results present that synergy effect of PxRex8A and PxXyl43A with PxXyn11A promotes xylan degradation into xylose.

Kinetics of cellulase-free endo xylanase hyper-synthesis by Aspergillus Niger using wheat bran as a potential solid substrate.

The present study deals with the production of cellulase-free endoxylanase by Aspergillus niger ISL-9 using wheat bran as a solid substrate. Endoxylanase was produced under a solid-state fermentation. Various growth parameters were optimized for the improved production of the enzyme. The Substrate level of 15 g was optimized as it provided the fungus with balanced aeration and nutrition. Among the six moisture contents investigated, Moisture Content 5 (MC5) was optimized (g/l: malt extract, 10; (NH4)2HPO4, 2.5; urea, 1.0) and 10 mL of MC5 was found to give the highest production of endoxylanase. The pH and time of incubation were optimized to 6.2 and 48 h respectively. The Inoculum size of 2 mL (1.4 × 106 spores/mL) gave the maximum enzyme production. After optimization of these growth parameters, a significantly high endoxylanase activity of 21.87 U/g was achieved. Very negligible Carboxymethylcellulase (CMCase) activity was observed indicating the production of cellulase-free endoxylanase. The notable finding is that the endoxylanase activity was increased by 1.4-fold under optimized conditions (p ≤ 0.05). The overall comparison of kinetic parameters for enhanced production of endoxylanase by A. niger ISL-9 under Solid State Fermentation (SSF) was also studied. Different kinetic variables which included specific growth rate, product yield coefficients, volumetric rates and specific rates were observed at 48, 72 and 96 h incubation time and were compared for MC1 and MC5. Among the kinetic parameters, the most significant result was obtained with volumetric rate constant for product formation (Qp) that was found to be optimum (1.89 U/h) at 72 h incubation period and a high value of Qp i.e.1.68 U/h was also observed at 48 h incubation period. Thus, the study demonstrates a cost-effective and environmentally sustainable process for xylanase production and exhibits scope towards successful industrial applications.

Novel approach on the evaluation of enzyme-aided alkaline extraction of polysaccharide from Hordeum vulgare husk and molecular insight on the multifunctional scaffold.

Hordeum vulgare husk, a cereal grain, is rich in dietary fiber and prebiotics beneficial for the gut microbiota and host organism. This study investigates the effects of barley husk-derived water-soluble xylan (BH-WSX) on gut homeostasis and the microbiome. We enzymatically extracted BH-WSX and evaluated its prebiotic and antioxidant properties. A 40.0 % (w/v) xylan yield was achieved, with the extracted xylan having a molecular mass of 212.0885 and a xylose to glucuronic acid molar ratio of 6:1. Specialized optical rotation research indicated that the isolated xylan is composed of monomeric sugars such as D-xylose, glucose, and arabinose. Fourier Transform Infrared (FTIR) spectroscopy revealed that the xylan comprises ß (1 â†’ 4) linked xylose units, randomly substituted with glucose residues, α-arabinofuranose, and acetyl groups. Nuclear Magnetic Resonance (NMR) analysis showed that the barley husk extract's backbone is substituted with 4-O-methyl glucuronic acid at the O2 position. Thermogravimetric analysis indicated that WSX exhibits a single sharp peak at 266 °C on the Differential Thermal Gravimetry (DTG) curve. Furthermore, a combination of in vitro, in vivo models, and molecular docking analysis elaborated on the anti-adhesion properties of BH-WSX. This study presents a novel approach to utilizing barley husk as an efficient source of functional polysaccharides for food-related industrial applications.

Quantitative analysis of intermolecular forces in cellulose microfibrils and hemicellulose with AFM nano-colloidal probes.

It is an interesting research topic to study the interfacial interactions between hemicellulose and cellulose, specifically how hemicellulose's structure affects its binding to cellulose nanofibers. Our research proposes that dispersion interaction play an important role in this interfacial interaction, more so than electrostatic forces when considering the adherence of cellulose to xylan. To quantify these interactions, the Atomic Force Microscope (AFM) colloidal probe technique is applied to measure the intermolecular forces between cellulose nanofibers, which are attached to the probe and xylan. These measured forces are then analyzed in relation to the length, diameter and functional groups of the nanocellulose, as well as the molecular weight and side chains of the xylan. Moreover, the predominance of dispersion forces by contrasting the adhesive forces before and after the grafting of a large nonpolar group onto xylan. This modification significantly reduces contact between the cellulose and xylan backbone, thereby markedly diminishing the dispersion interactions. Parallel to the AFM experiments, molecular dynamics (MD) simulations corroborate the experimental results and support our hypotheses. Collectively, these findings contribute to a deeper understanding of polysaccharide interactions within lignocellulose.

Identification of glycosyltransferases mediating 2-O-arabinopyranosyl and 2-O-galactosyl substitutions of glucuronosyl side chains of xylan.

Xylan is one of the major hemicelluloses in plant cell walls and its xylosyl backbone is often decorated at O-2 with glucuronic acid (GlcA) and/or methylglucuronic acid (MeGlcA) residues. The GlcA/MeGlcA side chains may be further substituted with 2-O-arabinopyranose (Arap) or 2-O-galactopyranose (Gal) residues in some plant species, but the enzymes responsible for these substitutions remain unknown. During our endeavor to investigate the enzymatic activities of Arabidopsis MUR3-clade members of the GT47 glycosyltransferase family, we found that one of them was able to transfer Arap from UDP-Arap onto O-2 of GlcA side chains of xylan, and thus it was named xylan 2-O-arabinopyranosyltransferase 1 (AtXAPT1). The function of AtXAPT1 was verified in planta by its T-DNA knockout mutation showing a loss of the Arap substitution on xylan GlcA side chains. Further biochemical characterization of XAPT close homologs from other plant species demonstrated that while the poplar ones had the same catalytic activity as AtXAPT1, those from Eucalyptus, lemon-scented gum, sea apple, 'Ohi'a lehua, duckweed and purple yam were capable of catalyzing both 2-O-Arap and 2-O-Gal substitutions of xylan GlcA side chains albeit with differential activities. Sequential reactions with XAPTs and glucuronoxylan methyltransferase 3 (GXM3) showed that XAPTs acted poorly on MeGlcA side chains, whereas GXM3 could efficiently methylate arabinosylated or galactosylated GlcA side chains of xylan. Furthermore, molecular docking and site-directed mutagenesis analyses of Eucalyptus XAPT1 revealed critical roles of several amino acid residues at the putative active site in its activity. Together, these findings establish that XAPTs residing in the MUR3 clade of family GT47 are responsible for 2-O-arabinopyranosylation and 2-O-galactosylation of GlcA side chains of xylan.

Polysaccharides Analysis of Cell Wall Using Carbohydrate Gel Electrophoresis.

The plant cell wall is rich in polysaccharides with high heterogeneity. Investigating the composition and structure of cell wall polysaccharides is crucial for understanding the functionalities of plant cell walls. Carbohydrate electrophoresis is a sensitive and rapid method to analyze polysaccharides qualitatively and quantitatively. The process includes digesting the polysaccharides with appropriate cleavage enzymes, labeling the reducing ends of the released oligosaccharides with a highly charged fluorophore, and separating the labeled oligosaccharides in a polyacrylamide gel via high-voltage electrophoresis. The generated fluorescence can be calculated as compared to that of oligosaccharide standards. Therefore, this is a convenient method for polysaccharide characterization that can be performed in most laboratories. Here, we introduce the detailed operational steps and precautions, which are helpful for researchers to quickly obtain the structural information of polysaccharides.

Aspergillus labruscus ITAL 22.223 xylanase - immobilization and application for the obtainment of corncob xylan targeting xylitol production.

Corncob is an agro-residue rich in lignocellulosic material that can be used for the xylitol production, through its enzymatic conversion obtaining fermentable sugars and their subsequent fermentation. In light of the above, this study targeted the immobilization of Aspergillus labruscus xylanase and the use of the derivative to hydrolyze the corncob xylan for the obtainment of xylose, and its subsequent use for the production of xylitol. The extracellular xylanase was immobilized using different supports (sodium alginate, DEAE-Cellulose, DEAE-Sephadex and CM-Sephadex). Among all supports used, the best results were obtained with the DEAE-Cellulose derivative showing an efficiency of immobilization of 97-99%, yield of 93-95% and recovered activity of 81-100%. The sodium alginate derivative showed 3 cycles of reuse, with drop in activity of about 65% in the 3rd cycle using both CaCl2 and MnCl2 as crosslinkers. The best enzymatic activity for the DEAE-Cellulose derivative was observed at 55ºC and pH 5.0. This derivative presented reuse of 10 cycles using commercial xylan as substrate, and 4 cycles using corncob xylan. This derivative was used in an enzymatic reactor to hydrolyze corncob xylan, obtaining 2.7 mg/mL of xylose after 48 h of operation under optimal condition of temperature and pH. The xylose obtained from the corncob was fermented by Candida tropicalis for 96 h with consumption of 60%. The HPLC analyses indicated a production of 1.02 mg/mL of xylitol with 48 h of fermentation. In conclusion, this is the first report on the immobilization of the A. labrucus xylanase as an alternative for the obtainment of xylose from corncob xylan, and the subsequent production of xylitol.

High-efficiency conversion of corn bran to ethanol at 150 L scale.

Fractionated corn bran was processed to maximize ethanol production from starch, cellulose, and xylan. After various bench-scale experiments, an optimized process with dilute acid pretreatment (1.5 % w/w H2SO4) at 90 °C for 60 min was utilized followed by enzymatic hydrolysis using cellulase and hemicellulase for 48 hr. After simultaneous saccharification (regarding starch) and fermentation at 150 L using an engineered yeast, which consumes both glucose and xylose to make ethanol, the 86 % total sugar conversion yield was achieved, including conversions of 95 % for starch, 77 % for cellulose and 77 % for xylan. Also, an accurate mass balance was formulated for ethanol-producing carbohydrates including starch, cellulose, and xylan from feedstock to final ethanol. A highly efficient process of converting corn fiber to ethanol was successfully scaled up to 150 L.

Genome-wide analysis and identification of the TBL gene family in Eucalyptus grandis.

The TRICHOME BIREFRINGENCE-LIKE (TBL) gene encodes a class of proteins related to xylan acetylation, which has been shown to play an important role in plant response to environmental stresses. This gene family has been meticulously investigated in Arabidopsis thaliana, whereas there have been no related reports in Eucalyptus grandis. In this study, we identified 49 TBL genes in E. grandis. A conserved amino acid motif was identified, which plays an important role in the execution of the function of TBL gene family members. The expression of TBL genes was generally upregulated in jasmonic acid-treated experiments, whereas it has been found that jasmonic acid activates the expression of genes involved in the defense functions of the plant body, suggesting that TBL genes play an important function in the response of the plant to stress. The principle of the action of TBL genes is supported by the finding that the xylan acetylation process increases the rigidity of the cell wall of the plant body and thus improves the plant's resistance to stress. The results of this study provide new information about the TBL gene family in E. grandis and will help in the study of the evolution, inheritance, and function of TBL genes in E. grandis, while confirming their functions.

Enrichment of Aquatic Xylan-Degrading Microbial Communities.

The transition towards a sustainable society involves the utilization of lignocellulosic biomass as a renewable feedstock for materials, fuel, and base chemicals. Lignocellulose consists of cellulose, hemicellulose, and lignin, forming a complex, recalcitrant matrix where efficient enzymatic saccharification is pivotal for accessing its valuable components. This study investigated microbial communities from brackish Lauwersmeer Lake, in The Netherlands, as a potential source of xylan-degrading enzymes. Environmental sediment samples were enriched with wheat arabinoxylan (WAX) and beechwood glucuronoxylan (BEX), with enrichment on WAX showing higher bacterial growth and complete xylan degradation compared to BEX. Metagenomic sequencing revealed communities consisting almost entirely of bacteria (>99%) and substantial shifts in composition during the enrichment. The first generation of seven-day enrichments on both xylans led to a high accumulation of Gammaproteobacteria (49% WAX, 84% BEX), which were largely replaced by Alphaproteobacteria (42% WAX, 69% BEX) in the fourth generation. Analysis of the protein function within the sequenced genomes showed elevated levels of genes associated with the carbohydrate catabolic process, specifically targeting arabinose, xylose, and xylan, indicating an adaptation to the primary monosaccharides present in the carbon source. The data open up the possibility of discovering novel xylan-degrading proteins from other sources aside from the thoroughly studied Bacteroidota.

Plant Cell Wall Polysaccharide O-Acetyltransferases.

Plant cell walls are largely composed of polysaccharide polymers, including cellulose, hemicelluloses (xyloglucan, xylan, mannan, and mixed-linkage ß-1,3/1,4-glucan), and pectins. Among these cell wall polysaccharides, xyloglucan, xylan, mannan, and pectins are often O-acetylated, and polysaccharide O-acetylation plays important roles in cell wall assembly and disease resistance. Genetic and biochemical analyses have implicated the involvement of three groups of proteins in plant cell wall polysaccharide O-acetylation: trichome birefringence-like (TBL)/domain of unknown function 231 (DUF231), reduced wall acetylation (RWA), and altered xyloglucan 9 (AXY9). Although the exact roles of RWAs and AXY9 are yet to be identified, members of the TBL/DUF231 family have been found to be O-acetyltransferases responsible for the O-acetylation of xyloglucan, xylan, mannan, and pectins. Here, we provide a comprehensive overview of the occurrence of O-acetylated cell wall polysaccharides, the biochemical properties, structural features, and evolution of cell wall polysaccharide O-acetyltransferases, and the potential biotechnological applications of manipulations of cell wall polysaccharide acetylation. Further in-depth studies of the biochemical mechanisms of cell wall polysaccharide O-acetylation will not only enrich our understanding of cell wall biology, but also have important implications in engineering plants with increased disease resistance and reduced recalcitrance for biofuel production.

Fibrobacter sp. HC4, a newly isolated strain, demonstrates a high cellulolytic activity as revealed by enzymatic measurements and in vitro assay.

Despite their low quantity and abundance, the cellulolytic bacteria that inhabit the equine large intestine are vital to their host, as they enable the crucial use of forage-based diets. Fibrobacter succinogenes is one of the most important intestinal cellulolytic bacteria. In this study, Fibrobacter sp. HC4, one cellulolytic strain newly isolated from the horse cecum, was characterized for its ability to utilize plant cell wall fibers. Fibrobacter sp. HC4 consumed only cellulose, cellobiose, and glucose and produced succinate and acetate in equal amounts. Among genes coding for CAZymes, 26% of the detected glycoside hydrolases (GHs) were involved in cellulolysis. These cellulases belong to the GH5, GH8, GH9, GH44, GH45, and GH51 families. Both carboxymethyl cellulase and xylanase activities of Fibrobacter sp. HC4 were detected using the Congo red method and were higher than those of F. succinogenes S85, the type strain. The in vitro addition of Fibrobacter sp. HC4 to a fecal microbial ecosystem of horses with large intestinal acidosis significantly enhanced fibrolytic activity as measured by the increase in gas and volatile fatty acids production during the first 48 h. According to this, the pH decreased and the disappearance of dry matter increased at a faster rate with Fibrobacter sp. HC4. Our data suggest a high specialization of the new strain in cellulose degradation. Such a strain could be of interest for future exploitation of its probiotic potential, which needs to be further determined by in vivo studies.IMPORTANCECellulose is the most abundant of plant cell wall fiber and can only be degraded by the large intestine microbiota, resulting in the production of volatile fatty acids that are essential for the host nutrition and health. Consequently, cellulolytic bacteria are of major importance to herbivores. However, these bacteria are challenged by various factors, such as high starch diets, which acidify the ecosystem and reduce their numbers and activity. This can lead to an imbalance in the gut microbiota and digestive problems such as colic, a major cause of mortality in horses. In this work, we characterized a newly isolated cellulolytic strain, Fibrobacter sp. HC4, from the equine intestinal microbiota. Due to its high cellulolytic capacity, reintroduction of this strain into an equine fecal ecosystem stimulates hay fermentation in vitro. Isolating and describing cellulolytic bacteria is a prerequisite for using them as probiotics to restore intestinal balance.