pH-controlled acetic acid pretreatment for coproduction of low degree of polymerization xylo-oligosaccharides and glucose from corncobs.

Acetic acid (HAc) pretreatment has been widely used for the production of xylo-oligosaccharides (XOS), requiring harsh reaction conditions because XOS are intermediates during the xylan degradation process. This complexity makes the pretreatment process difficult to regulate. In this study, a pH-controlled HAc pretreatment using sodium hydroxide (NaOH) was proposed to enhance the yield of XOS and to reduce its degree of polymerization (DP) from corncobs (CC). By employing this method (0.3 M-2.7), 49.7 % of XOS with DP 2-6 was obtained, alongside a notable increase in the fraction of XOS with DP 2-4 (10.1 g/L). This performance significantly surpassed that of the HAc alone (0.3 M). Moreover, the glucose yield from CC via pH-controlled HAc pretreatment was as high as 93.1 % after 72-h enzymatic hydrolysis. These results suggested that the pH-controlled HAc pretreatment could be a promising strategy for the coproduction of low-DP XOS and fermentable sugars.

Effect of xylo-oligosaccharides on intestinal bacterial diversity in mice with spleen deficiency constipation.

Objective: To explore the effect of xylo-oligosaccharides on intestinal bacterial diversity in mice with spleen deficiency constipation. Methods: The 16S rDNA sequencing was used to identify microbiota composition in four groups, including the normal group (NG), the model group with spleen-deficiency constipation (SDC), XOS treated groups that include XOS1 groups treated XOS 0.05 g/mL•d, and XOS2 group treated XOS 0.1 g/mL•d. Chao1 and Shannon were used to conduct gut microbes diversity analysis. Linear discriminant analysis coupled with effect size measurements (LEfSe) was used to identify signature gut microbiota, and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) was used to predict the function of altered gut microbiota. Results: Veen map indicated 245 common OTUs were identified from four groups. Especially, 9, 3, 0, and 19 unique OTUs were identified in NG, SDC, XOS1, and XOS2 groups, respectively. The Shannon index was evidently higher in NG group than in the other three groups (p < 0.05). We identified the occurrence of dominant bacterial groups including Bacteroidetes (25.5 ~ 49.9%), Firmicutes (25.4 ~ 39.3%), Proteobacteria (12.5 ~ 24.9%), Deferribacteres (1.6 ~ 19.2%), Cyanobacteria (0.3 ~ 1.8%), Verrucomicrobia (0.02 ~ 1.6%), Actinobacteria (0.01 ~ 0.5%), and Tenericutes (0.03 ~ 0.09%) at the four groups. The XOS2 group was characterized by a higher abundance of Peptostreptococcaceae, Intestinibacter, Aerococcaceae, and Facklamia. XOS1 group enriched in Deferribacteres, Mucispirillum, Deferribacterales, Deferribacteres, Lachnoclostridium, Rhodospirillaceae, and Rhodospirillales. Meanwhile, the SDC mice showed dramatic enrichment in Rikenellaceae, Lachnospiraceae, Rikenellaceae, Roseburia, and Alistipes, which were highly abundant in the NG group. XOS fed-mice evidently increase Deferribcteres abundance compared with NG and SDC groups. However, the abundance of Rikenellaceae was significantly reduced in XOS1 and XOS2 groups compared with NG and SDC groups. We identified that altered gut microbiotas by XOS treatment were associated with various metabolic pathways, including organismal systems, metabolism, human diseases, genetic information processing, and cellular processes. Conclusion: Our research indicated that XOS has the potential to recover intestinal bacteria and contribute to the treatment of spleen deficiency constipation.

Youth-derived Lactobacillus rhamnosus with prebiotic xylo-oligosaccharide exhibits anti-hyperlipidemic effects as a novel synbiotic.

Changes in dietary patterns and living habits have led to an increasing number of individuals with elevated cholesterol levels. Excessive consumption of high-cholesterol foods can disrupt the body's lipid metabolism. Numerous studies have firmly established the cholesterol-lowering effects of probiotics and prebiotics, with evidence showing that the synergistic use of synbiotics is functionally more potent than using probiotics or prebiotics alone. Currently, the screening strategy involves screening prebiotics for synbiotic development with probiotics as the core. However, in comparison to probiotics, there are fewer types of prebiotics available, leading to limited resources. Consequently, the combinations of synbiotics obtained are restricted, and probiotics and prebiotics are only relatively suitable. Therefore, in this study, a novel synbiotic screening strategy with prebiotics as the core was developed. The synbiotic combination of Lactobacillus rhamnosus S_82 and xylo-oligosaccharides was screened from the intestinal tract of young people through five generations of xylo-oligosaccharides. Subsequently, the cholesterol-lowering ability of the medium was simulated, and the two carbon sources of glucose and xylo-oligosaccharides were screened out. The results showed that synbiotics may participate in cholesterol-lowering regulation by down-regulating the expression of NPC1L1 gene, down-regulating ACAT2 and increasing the expression of ABCG8 gene in vitro through cell adsorption and cell absorption in vitro, and regulating the intestinal microbiota. Synbiotics hold promise as potential candidates for the prevention of hypercholesterolemia in humans and animals, and this study providing a theoretical foundation for the development of new synbiotic products.

Sunflower Meal Valorization through Enzyme-Aided Fractionation and the Production of Emerging Prebiotics.

Recently, there has been a burgeoning interest in harnessing the potential of biomass and industry byproducts for the development of novel products and materials. In particular, this study explored the efficient valorization of sunflower meal (SFM), an underutilized byproduct of the oil extraction industry, usually discarded or used as low-value animal feed through enzyme-aided fractionation, specifically targeting the extraction and conversion of its abundant carbohydrate component, xylan, into emerging prebiotic compounds-xylo-oligosaccharides (XOSs)-which are recognized as promotors of a healthy gut microbiome and overall human wellbeing. An enzymatic treatment using Alcalase® 2.4 L was implemented for facilitating the recovery of a highly pure hemicellulosic fraction (92.2% carbohydrates) rich in ß-(1→4)-linked xylose residues with arabinose and glucuronic acid substitutions (DP-xylan). A further enzymatic treatment of this substrate, using ROHALASE® SEP-VISCO under optimized conditions (70 °C, pH 6, 0.005% v/v enzyme concentration), produced 52.3% of XOSs with a polymerization degree (DP) less than 20 after two hours. Further analyses demonstrated that the majority of the obtained product had a DP less than 6, predominantly consisting of di- and trisaccharides (XOS2 and XOS3) without the significant generation of xylose. These findings highlight the significant potential of SFM for the generation of valuable prebiotic compounds in a sustainable manner.

Dietary xylo-oligosaccharides alleviates LPS-induced intestinal injury via endoplasmic reticulum-mitochondrial system pathway in piglets.

The beneficial effects of xylo-oligosaccharides (XOS) on the intestine have been widely reported, including anti-inflammation, antioxidant, maintenance of intestinal epithelial barrier, and treatment of intestinal injury. However, the specific mechanism of XOS in mitigating intestinal injury in weaned piglets remains unclear. Therefore, this study aimed to explore the specific mechanism of XOS in mitigating intestinal injury. The study is a complete randomized design with 24 weaned piglets in a 2 × 2 factorial arrangement that includes diet treatments (basal diet vs. 0.02% XOS) and immunological challenge [saline vs. lipopolysaccharide (LPS)]. All piglets were fed a basal diet or a XOS diet for 21 d. On day 22, all piglets received an injection of LPS or saline. In this study, dietary XOS increased jejunal villus height, reduced crypt depth and oxidative stress, and enhanced the gene and protein expression of Claudin-1, Occludin, and zonula occludens 1 (P < 0.05). The piglets fed the XOS diet had lower serum Diamine oxidase activity and d-lactic acid content (P < 0.05). In addition, dietary XOS regulates endoplasmic reticulum (ER)-mitochondria system function and the expression of key molecules, including mitochondrial dynamics dysfunction [mitofusin (Mfn)-1, optic atrophy 1, fission 1, and dynamin-related protein 1], ER stress [activating transcription factor 4 (ATF4), ATF6, C/EBP-homologous protein, eukaryotic initiation factor 2α, glucose-regulated protein (GRP) 78, GRP94, and protein kinase R-like ER kinase] and the mitochondria-associated ER membranes (MAM) disorders (Mfn2, GRP75, and voltage-dependent anion channel 1) (P < 0.05). Therefore, the findings to indicate that dietary XOS is effective against LPS-induced jejunal injury may be attributed to its ability to alleviate mitochondrial dynamics dysfunction, ER stress, and MAM disorders.

Intestinal injury can have a range of negative impacts on weaned piglets. Xylo-oligosaccharides are known for their beneficial effects on the gut, including anti-inflammatory and antioxidant properties, and also help maintain the intestinal epithelial barrier and reduce intestinal injury. However, the exact mechanism by which xylo-oligosaccharides reduce intestinal injury in piglets remains unclear. The endoplasmic reticulum­mitochondrial system, endoplasmic reticulum and mitochondria, along with the mitochondria-associated endoplasmic reticulum membranes that connect them, plays a crucial role in mediating intestinal injury in piglets. Therefore, this study aimed to investigate whether xylo-oligosaccharides affect intestinal injury in piglets through the endoplasmic reticulum, mitochondria, and the mitochondria-associated endoplasmic reticulum membranes. The results of this study indicate that xylo-oligosaccharides mitigate intestinal injury in piglets by alleviating endoplasmic reticulum stress, mitochondrial dynamics dysfunction, and mitochondria-related endoplasmic reticulum membrane disorders, providing a theoretical basis for the treatment of intestinal injury with xylo-oligosaccharides.

Co-administration of xylo-oligosaccharides produced by immobilized Aspergillus terreus xylanase with carbimazole to mitigate its adverse effects on the adrenal gland.

Carbimazole has disadvantages on different body organs, especially the thyroid gland and, rarely, the adrenal glands. Most studies have not suggested any solution or medication for ameliorating the noxious effects of drugs on the glands. Our study focused on the production of xylooligosaccharide (XOS), which, when coadministered with carbimazole, relieves the toxic effects of the drug on the adrenal glands. In addition to accelerating the regeneration of adrenal gland cells, XOS significantly decreases the oxidative stress caused by obesity. This XOS produced by Aspergillus terreus xylanase was covalently immobilized using microbial Scleroglucan gel beads, which improved the immobilization yield, efficiency, and operational stability. Over a wide pH range (6-7.5), the covalent immobilization of xylanase on scleroglucan increased xylanase activity compared to that of its free form. Additionally, the reaction temperature was increased to 65 °C. However, the immobilized enzyme demonstrated superior thermal stability, sustaining 80.22% of its original activity at 60 °C for 120 min. Additionally, the full activity of the immobilized enzyme was sustained after 12 consecutive cycles, and the activity reached 78.33% after 18 cycles. After 41 days of storage at 4 °C, the immobilized enzyme was still active at approximately 98%. The immobilized enzyme has the capability to produce xylo-oligosaccharides (XOSs). Subsequently, these XOSs can be coadministered alongside carbimazole to mitigate the adverse effects of the drug on the adrenal glands. In addition to accelerating the regeneration of adrenal gland cells, XOS significantly decreases the oxidative stress caused by obesity.

Production and biological activity of ß-1,3-xylo-oligosaccharides using xylanase from Caulerpa lentillifera.

In this study, ß-1,3-xylanase (Xyl3088) was designed and prepared by constructing the expression vector plasmid and expressing and purifying the fusion protein. ß-1,3-xylo-oligosaccharides were obtained through the specific enzymatic degradation of ß-1, 3-xylan from Caulerpa lentillifera. The enzymolysis conditions were established and optimized as follows: Tris-HCl solution 0.05 mol/L, temperature of 37 °C, enzyme amount of 250 µL, and enzymolysis time of 24 h. The oligosaccharides' compositions and structural characterization were identified by thin-layer chromatography (TLC), ion chromatography (IC) and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS). The IC50 values for scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethyl-benzothiazoline-p-sulfonic acid (ABTS+), and superoxide anion radical (•O2-) were 13.108, 1.258, and 65.926 mg/mL for ß-1,3-xylo-oligosaccharides, respectively, and 27.588, 373.048, and 269.12 mg/mL for ß-1,4-xylo-oligosaccharides, respectively. Compared with ß-1,4-xylo-oligosaccharides, ß-1,3-xylo-oligosaccharides had substantial antioxidant activity and their antioxidant effects were concentration dependent. ß-1,3-xylo-oligosaccharides also possessed a stronger anti-inflammatory effect on RAW 264.7 cells stimulated by lipopolysaccharide (LPS) than ß-1,4-xylo-oligosaccharides. At a working concentration of 100 µg/mL, ß-1,3-xylo-oligosaccharides inhibited the release of NO and affected the expression of IL-1ß, TNF-α, and other proteins secreted by cells, effectively promoting the release of pro-inflammatory mediators by immune cells in response to external stimuli and achieving anti-inflammatory effects. Therefore, ß-1,3-xylo-oligosaccharides are valuable products in food and pharmaceutical industries.

Effects of xylo-oligosaccharide on gut microbiota, brain protein expression, and lipid profile induced by high-fat diet.

Midlife overweight and obesity are risk factors of cognitive decline and Alzheimer' s disease (AD) in late life. In addition to increasing risk of obesity and cognitive dysfunction, diets rich in fats also contributes to an imbalance of gut microbiota. Xylo-oligosaccharides (XOS) are a kind of prebiotic with several biological advantages, and can selectively promote the growth of beneficial microorganisms in the gut. To explore whether XOS can alleviate cognitive decline induced by high-fat diet (HFD) through improving gut microbiota composition, mice were fed with normal control or 60% HFD for 9 weeks to induce obesity. After that, mice were supplemented with XOS (30 g or 60 g/kg-diet) or without, respectively, for 12 weeks. The results showed that XOS inhibited weight gain, decreased epidydimal fat weight, and improved fasting blood sugar and blood lipids in mice. Additionally, XOS elevated spatial learning and memory function, decreased amyloid plaques accumulation, increased brain-derived neurotrophic factor levels, and improved neuroinflammation status in hippocampus. Changes in glycerolipids metabolism-associated lipid compounds caused by HFD in hippocampus were reversed after XOS intervention. On the other hand, after XOS intervention, increase in immune-mediated bacteria, Faecalibacterium was observed. In conclusion, XOS improved gut dysbiosis and ameliorated spatial learning and memory dysfunction caused by HFD by decreasing cognitive decline-associated biomarkers and changing lipid composition in hippocampus.

Dietary xylo-oligosaccharides and arabinoxylans improved growth efficiency by reducing gut epithelial cell turnover in broiler chickens.

BACKGROUND: One of the main roles of the intestinal mucosa is to protect against environmental hazards. Supplementation of xylo-oligosaccharides (XOS) is known to selectively stimulate the growth of beneficial intestinal bacteria and improve gut health and function in chickens. XOS may have an impact on the integrity of the intestinal epithelia where cell turnover is critical to maintain the compatibility between the digestive and barrier functions. The aim of the study was to evaluate the effect of XOS and an arabinoxylan-rich fraction (AXRF) supplementation on gut function and epithelial integrity in broiler chickens. METHODS: A total of 128 broiler chickens (Ross 308) were assigned into one of two different dietary treatments for a period of 42 d: 1) control diet consisting of a corn/soybean meal-based diet; or 2) a control diet supplemented with 0.5% XOS and 1% AXRF. Each treatment was randomly distributed across 8 pens (n = 8) with 8 chickens each. Feed intake and body weight were recorded weekly. On d 42, one male chicken per pen was selected based on average weight and euthanized, jejunum samples were collected for proteomics analysis. RESULTS: Dietary XOS/AXRF supplementation improved feed efficiency (P < 0.05) from d 1 to 42 compared to the control group. Proteomic analysis was used to understand the mechanism of improved efficiency uncovering 346 differentially abundant proteins (DAP) (Padj < 0.00001) in supplemented chickens compared to the non-supplemented group. In the jejunum, the DAP translated into decreased ATP production indicating lower energy expenditure by the tissue (e.g., inhibition of glycolysis and tricarboxylic acid cycle pathways). In addition, DAP were associated with decreased epithelial cell differentiation, and migration by reducing the actin polymerization pathway. Putting the two main pathways together, XOS/AXRF supplementation may decrease around 19% the energy required for the maintenance of the gastrointestinal tract. CONCLUSIONS: Dietary XOS/AXRF supplementation improved growth efficiency by reducing epithelial cell migration and differentiation (hence, turnover), actin polymerization, and consequently energy requirement for maintenance of the jejunum of broiler chickens.

Xylo-oligosaccharides improve functional constipation by targeted enrichment of Bifidobacterium.

Functional constipation (FC) has a negative impact on patients' quality of life. We hypothesized that dietary supplementation with xylo-oligosaccharides (XOS) or fructo-oligosaccharides (FOS) would improve constipation symptoms by influencing the gut microbiota. A randomized double-blind controlled trial was conducted in FC patients. Patients were randomly divided into 6 groups and given a dietary supplement containing XOS at doses of 3, 5, or 10 g/day, FOS at doses of 10 and 20 g/day, or placebo at 5 g/day for one month. We compared improvements in gastrointestinal function after the intervention using the Bristol Stool Form Scale (BSFS), Cleveland Clinic Constipation Score (CCCS), and Quality of Life Scale for Patients with Constipation (PAC-QoL). 16S rRNA sequencing was used to assess changes in the structure of the gut microbiota. Changes in individual bacteria had significant effects in reducing gastrointestinal symptoms during the intervention, even though the flora structure remained unchanged from baseline. Compared to FOS, XOS enriched Bifidobacterium at a lower dose, and patients receiving XOS supplementation showed significant improvements in constipation symptoms without side effects such as diarrhea and flatulence.

Multi-point immobilization of GH 11 endo-ß-1,4-xylanase on magnetic MOF composites for higher yield of xylo-oligosaccharides.

GH 11 endo-ß-1,4-xylanase (Xy) was a crucial enzyme for xylooligosaccharides (XOS) production. The lower reusability and higher cost of purification has limited the industrial application of Xy. Addressing these challenges, our study utilized various immobilization techniques, different supports and forces for Xy immobilization. This study presents a new method in the development of Fe3O4@PDA@MOF-Xy which is immobilized via multi-point interaction forces, demonstrating a significant advancement in protein loading capacity (80.67 mg/g), and exhibiting remarkable tolerance to acidic and alkaline conditions. This method significantly improved Xy reusability and efficiency for industrial applications, maintaining 60 % activity over 10 cycles. Approximately 23 % XOS production was achieved by Fe3O4@PDA@MOF-Xy. Moreover, the yield of XOS from cobcorn xylan using this system was 1.15 times higher than that of the free enzyme system. These results provide a theoretical and applicative basis for enzyme immobilization and XOS industrial production.

Structural characterization of lignin from the green pretreatments for co-producing xylo-oligosaccharides and glucose: Toward full biomass utilization.

Three green non-enzymatic catalysis pretreatments (NECPs) including autohydrolysis, subcritical CO2-assisted seawater autohydrolysis, and inorganic salt catalysis were utilized to simultaneously produce xylo-oligosaccharides (XOS), glucose, and cellulolytic enzyme lignin (CEL) from sugarcane bagasse (SCB). The yield of XOS in all three NECPs was over 50 % with a competitive glucose yield of enzymatic hydrolysis. And the effects of different pretreatments on the chemical structure and composition of CEL samples were also investigated. The pretreatments significantly increased the thermal stability, yield, and purity of the CEL samples. Moreover, the net yield of lignin was 58.3 % with lignin purity was 98.9 % in the autohydrolysis system. Furthermore, there was a decrease in the molecular weight of CEL samples as the pretreatment intensity increased. And the original lignin structural units sustained less damage during the NECPs, due to the cleavage of the ß-O-4 bonds dominating lignin degradation. Meanwhile, these pretreatments increased the phenolic-OH in CEL samples, making the lignin more reactive, and enhancing its subsequent modification and utilization. Collectively, the described techniques have demonstrated practical significance for the coproduction of XOS and glucose, and lignin, providing a promising strategy for full utilization of biomass.

Effects of xylanase, protease, and xylo-oligosaccharides on growth performance, nutrient utilization, short chain fatty acids, and microbiota in Eimeria-challenged broiler chickens fed high fiber diet.

A 21-d experiment was conducted to study the effect of xylanase, protease, and xylo-oligosaccharides on growth performance, nutrient utilization, gene expression of nutrient transporters, cecal short-chain fatty acids (SCFA), and cecal microbiota profile of broilers challenged with mixed Eimeria spp. The study utilized 392 zero-d-old male broiler chicks allocated to 8 treatments in a 4 × 2 factorial arrangement, as follows: corn-soybean meal diet with no enzyme (Con); Con plus xylanase alone (XYL); Con plus xylanase combined with protease (XYL + PRO); or Con plus xylo-oligosaccharides (XOS); with or without Eimeria challenge. Diets were based on a high-fiber (100 g/kg soluble fibers and 14 g/kg insoluble fibers) basal diet. At d 15, birds in challenged treatment were gavaged with a solution containing Eimeria maxima, Eimeria acervulina, and Eimeria tenella oocysts. At d 21, birds were sampled. Eimeria depressed (P < 0.01) growth performance and nutrient utilization, whereas supplementation had no effect. There were significant Eimeria × supplementation interactions for the sugar transporters GLUT5 (P = 0.02), SGLT1 (P = 0.01), SGLT4 (P < 0.01), and peptide transporter PepT1 (P < 0.01) in jejunal mucosa. Eimeria challenge increased the expression of GM-CSF2 (P < 0.01) and IL-17 (P = 0.04) but decreased (P = 0.03) IL-1ß expression in the cecal tonsil. Eimeria × supplementation interactions for cecal acetate, butyrate, and total SCFA showed that concentrations increased or tended to be greater in the supplemented treatments, but only in non-challenged birds. Birds challenged with Eimeria spp. had higher concentrations of isobutyrate (P < 0.01), isovalerate (P < 0.01), and valerate (P = 0.02) in cecal content. Eimeria challenge significantly (P < 0.01) decreased the microbial richness and diversity, and increased (P < 0.01) the proportion of Anaerostipes butyraticus, Bifidobacterium pseudolongum, and Lactobacillus pontis. In conclusion, Eimeria infection depressed growth performance, nutrient utilization with regulating nutrient transporters. Furthermore, Eimeria challenge shifted the microbial profile and reduced microbial richness and diversity. On the other hand, enzyme supplementation showed limited benefits, which included increased concentrations of SCFA.

Toward Renewable-Based Prebiotics from Woody Biomass: Potential of Tailored Xylo-Oligosaccharides Obtained by Enzymatic Hydrolysis of Beechwood Xylan as a Prebiotic Feed Supplement for Young Broilers.

Although antibiotic resistance emerges naturally, this process has been accelerated by the worldwide overuse and misuse of antibiotics. It is essential to find effective alternatives in the broiler industry to improve poultry health while maintaining production efficiency and product safety. In this study, we aimed to evaluate a potential alternative: wood-derived xylo-oligosaccharides (XOS). The objective of this research was to investigate the potential of XOS prepared using enzymatic hydrolysis of beechwood xylan as a prebiotic feed supplement for broilers. A pilot study was conducted to explore the optimal XOS fraction profile by in vitro fermentation. Subsequently, a semi-continuous enzyme membrane reactor was used, allowing for the production of tailored XOS in large quantities. Given the strong bidirectional relationship between intestinal health, nutrition, and intestinal microbiota composition in broilers, an in vivo experiment was performed to explore the potential of XOS as a prebiotic feed supplement by investigating growth performance, feed conversion ratio, caecal short and medium chain fatty acid (SCFA and MCFA) concentration, and microbiological composition of the caecal content. Results from the pilot study indicated that higher enzyme concentrations in the hydrolysis process yield a product that leads to a higher total SCFA and MCFA- and butyric acid production during in vitro fermentation by caecal bacteria. Supplementation of the tailored XOS to the broiler diet (day 1 (d1)-d8 0.13% wt/wt XOS, d9-d15 0.32% XOS) resulted in higher Bifidobacterium counts, beneficial to the health of birds, on d11 and d15.

Discovery of novel alkaline-tolerant xylanases from fecal microbiota of dairy cows.

Xylo-oligosaccharides (XOS) are considered as a promising type of prebiotics that can be used in foods, feeds, and healthcare products. Xylanases play a key role in the production of XOS from xylan. In this study, we conducted a metagenomic analysis of the fecal microbiota from dairy cows fed with different types of fodders. Despite the diversity in their diets, the main phyla observed in all fecal microbiota were Firmicutes and Bacteroidetes. At the genus level, one group of dairy cows that were fed probiotic fermented herbal mixture-containing fodders displayed decreased abundance of Methanobrevibacter and increased growth of beneficial Akkermansia bacteria. Additionally, this group exhibited a high microbial richness and diversity. Through our analysis, we obtained a comprehensive dataset comprising over 280,000 carbohydrate-active enzyme genes. Among these, we identified a total of 163 potential xylanase genes and subsequently expressed 34 of them in Escherichia coli. Out of the 34 expressed genes, two alkaline xylanases with excellent temperature stability and pH tolerance were obtained. Notably, CDW-xyl-8 exhibited xylanase activity of 96.1 ± 7.5 U/mg protein, with an optimal working temperature of 55 â„ƒ and optimal pH of 8.0. CDW-xyl-16 displayed an activity of 427.3 ± 9.1 U/mg protein with an optimal pH of 8.5 and an optimal temperature at 40 â„ƒ. Bioinformatic analyses and structural modeling suggest that CDW-xyl-8 belongs to GH10 family xylanase, and CDW-xyl-16 is a GH11 family xylanase. Both enzymes have the ability to hydrolyze beechwood xylan and produce XOS. In conclusion, this metagenomic study provides valuable insights into the fecal microbiota composition of dairy cows fed different fodder types, revealing main microbial groups and demonstrating the abundance of xylanases. Furthermore, the characterization of two novel xylanases highlights their potential application in XOS production.

Xylo-oligosaccharide-based prebiotics upregulate the proteins of the Sus-like system in caecal Bacteroidetes of the chicken: evidence of stimbiotic mechanism.

The present study was conducted to investigate the stimbiotic mechanism of xylo-oligosaccharide (XOS) in degrading the complex polysaccharides by the caecal bacteria of the chicken, by applying a proteomic approach. A total of 800 as-hatched Ross 308 broiler chicks were equally divided into 4 experimental pens (200 chicks per pen) at a commercial poultry barn, allocating 2 pens per treatment. Birds were fed ad libitum with 2 dietary treatments; CON (without XOS) and XOS (with 0.1g XOS/kg diet) from d 0 to 35. From each pen, 60 Individual birds were weighed weekly whereas caecal content was obtained from 5 birds cervically dislocated on d 35. The caecal bacteria were lysed and their proteins were quantified using label-free quantitative proteomic mass spectrometry. The results showed that XOS significantly increased (P < 0.05) bird weight on d 7, 14, 21, and 28, and body weight gain on d 7, 14, 21, and 35 compared to CON. However, no difference (P > 0.05) in body weight gain was observed from d 0 to 35 between CON and XOS. The proteomic analysis of caecal bacteria revealed that 29 proteins were expressed differently between the CON and the XOS group. Out of 29, 20 proteins were significantly increased in the XOS group compared to CON and 9 of those proteins belonged to the starch-utilizing system (Sus)-like system of the gram-negative Bacteroidetes. Bacteroides thetaiotaomicron (Bt) is a significant constituent of the human gut microbiota, known for its remarkable ability to hydrolyze most glycosidic bonds of polysaccharides. This microorganism possesses a 5-protein complex in its outer membrane, named the starch utilization system (Sus), responsible for adhering to, breaking down, and transporting starch into the cell. Sus serves as an exemplar system for numerous polysaccharide utilization loci that target glycans found in Bt and other members of the Bacteroidetes phylum. The proteins of the Sus-like system are involved in the degradation of complex polysaccharides and transportation of the oligosaccharides into the periplasm of the caecal bacteria where they are further broken down into smaller units. These smaller units are then transported into the cytoplasm of the cell where they are utilized in metabolic pathways leading to potential generation of short-chain fatty acids, thus improving the nutritive value of residual feed. In conclusion, XOS supplementation upregulates the expression of the proteins of the Sus-like system indicating its role as a stimbiotic.

Evaluating the In Vitro and In Vivo Prebiotic Effects of Different Xylo-Oligosaccharides Obtained from Bamboo Shoots by Hydrothermal Pretreatment Combined with Endo-Xylanase Hydrolysis.

Xylo-oligosaccharides (XOS) enriched with high fractions of X2-X3 are regarded as an effective prebiotic for regulating the intestinal microflora. In this study, the original XOS solution was obtained from bamboo shoots through hydrothermal pretreatment under optimized conditions. Subsequently, enzymatic hydrolysis with endo-xylanase was performed on the original XOS solution to enhance the abundance of the X2-X3 fractions. The results demonstrated that hydrothermal pretreatment yielded 21.24% of XOS in the hydrolysate solution, and subsequent enzymatic hydrolysis significantly increased the proportion of the X2-X3 fractions from 38.87% to 68.21%. Moreover, the XOS solutions with higher amounts of X2-X3 fractions exhibited superior performance in promoting the growth of probiotics such as Bifidobacterium adolescentis and Lactobacillus acidophilus in vitro, leading to increased production of short-chain fatty acids. In the in vivo colitis mouse model, XOS solutions with higher contents of X2-X3 fractions demonstrated enhanced efficacy against intestinal inflammation. Compared with the colitis mice (model group), the XOS solution with higher X2-X3 fractions (S1 group) could significantly increase the number of Streptomyces in the intestinal microflora, while the original XOS solution (S2 group) could significantly increase the number of Bacteroides in the intestinal microflora of colitis mice. In addition, the abundances of Alcaligenes and Pasteurella in the intestinal microflora of the S1 and S2 groups were much lower than in the model group. This effect was attributed to the ability of these XOS solutions to enhance species diversity, reversing the imbalance and disorder within the intestinal microflora. Overall, this work highlights the outstanding potential of XOS enriched with high contents of X2-X3 fractions as a regulator of the intestinal microbiota and as an anti-colitis agent.

Bioconversion of cellulose and hemicellulose in corn cob into L-lactic acid and xylo-oligosaccharides.

With the banning of antibiotic chemical feed additives, multi-functional bioactive feed additives have been extensively sought after by the feed industry. In this study, low-cost and renewable corn cobs were treated with liquid hot water and converted into bioactive xylo-oligosaccharides and L-lactic acid after enzymatic hydrolysis, strain activation, and fermentation under mild conditions, which achieved a full utilization of cellulose and hemicellulose in corn cobs. Simultaneous saccharification fermentation after strain activation with enzymatic hydrolysate delivered the highest conversion rate of glucose to L-lactic acid (93.00 %) and yielded 17.38 g/L L-lactic acid and 2.68 g/L xylo-oligosaccharides. On this basis, batch-feeding fermentation resulted in a 78.03 % conversion rate of glucose to L-lactic acid, 18.99 g/L L-lactic acid, and 2.84 g/L xylo-oligosaccharides. This work not only provided a green and clean bioconversion strategy to produce multi-functional feed additives but can also boost the full utilization of renewable and cheap biomass resources.

Expression and characterization of α-L-arabinofuranosidase derived from Aspergillus awamori and its enzymatic degradation of corn byproducts with xylanase.

In this study, α-L-arabinofuranosidase (AF) from Aspergillus awamori was heterologously expressed in Pichia pastoris X33, with a 1-fold increase in AF activity after codon and vector optimization. AF remained stable at 60-65 °C and displayed a broad pH stability range of 2.5-8.0. It also demonstrated considerable resistance to pepsin and trypsin. Furthermore, compared with xylanase alone, AF with xylanase exhibited a marked synergistic effect in the degradation of expanded corn bran, corn bran, and corn distillers' dried grains with solubles, reducing sugars by 3.6-fold, 1.4-fold, and 6.5-fold, respectively, with the degree of synergy increasing to 4.61, 2.44, and 5.4, respectively, while in vitro dry matter digestibility values were 17.6%, 5.2%, and 8.8%, respectively. After enzymatic saccharification, corn byproducts were converted to prebiotic xylo-oligosaccharides and arabinoses, thereby demonstrating the favorable properties of AF in the degradation of corn biomass and its byproducts.

The effects of protease, xylanase, and xylo-oligosaccharides on growth performance, nutrient utilization, short-chain fatty acids, and microbiota in Eimeria-challenged broiler chickens fed low-protein diet.

A total of 392 Cobb 500 off-sex male broiler chicks were used in a 21-day experiment to study the effect of protease, xylanase, and xylo-oligosaccharides (XOS) on improving growth performance, nutrient utilization (ileal digestibility and total tract retention), gene expression of nutrient transporters, cecal short-chain fatty acids (SCFAs), and microbiota profile of broilers challenged with Eimeria spp. Chicks at 0-day old were allocated to 8 treatments in a 4 × 2 factorial arrangement: 1) corn-soybean meal diet with no enzyme (Con); 2) Con plus 0.2 g/kg protease alone (PRO); 3) Con plus 0.2 g/kg protease combined with 0.1 g/kg xylanase (PRO + XYL); or 4) Con plus 0.5 g/kg xylo-oligosaccharides (XOS); with or without Eimeria challenge. The 4 diets were formulated to be marginally low in crude protein (183 g/kg). Challenged groups were inoculated with a solution containing E. maxima, E. acervulina, and E. tenella oocysts on d 15. Eimeria depressed (P < 0.01) growth performance and nutrient utilization. Supplemental protease improved (P < 0.05) body weight gain and feed intake in the prechallenge phase (d 0-15) but had no effect during the infection period (d 15-21). There was no interaction between infection and feed supplementation for nutrient utilization. The supplementations of either PRO or XOS alone increased (P < 0.01) total tract retention of Ca and tended (P < 0.1) to improve total tract retention of N, P, AME, and AMEn. Eimeria decreased (P < 0.05) expressions of GLUT2, GLUT5, PepT1, ATP2B1, CaSR, Calbidin D28K, NPT2, and ZnT1 but increased (P < 0.01) expression of GLUT1. XOS supplementation increased (P < 0.05) ATP2B1 expression. Protease decreased (P < 0.05) isobutyrate concentration in unchallenged treatments but not in challenged treatments. Eimeria decreased (P < 0.01) cecal saccharolytic SCFAs acetate and propionate but increased (P < 0.01) branched-chain fatty acid isovalerate. The supplementation of PRO + XYL or XOS increased (P < 0.05) cecal butyrate or decreased cecal isobutyrate concentrations, respectively. PRO + XYL and XOS decreased cecal protein levels in unchallenged birds but not challenged ones. Eimeria challenge significantly (P < 0.05) decreased the microbial richness (Observed features) and diversity (Shannon index and phylogenetic diversity) and changed the microbial composition by reducing the abundance of certain bacteria, such as Ruminococcus torques, and increasing the abundance of others, such as Anaerostipes. In contrast, none of the additives had any significant effect on the cecal microbial composition. In conclusion, PRO or XOS supplementation individually improved nutrient utilization. All the additives decreased the cecal content of branched-chain fatty acids, consistent with decreased cecal N concentration, although the effects were more pronounced in unchallenged birds. In addition, none of the feed additives impacted the Eimeria-induced microbial perturbation.