Xylooligosaccharides Research Articles

Research Note: Xylooligosaccharide directly attenuates Salmonella Typhimurium colonization and its induction of impairments in intestinal barrier and growth performance of broilers

Xylooligosaccharide (XOS) is known as a prebiotic, however, it is unknown whether XOS can directly protect against bacterial infection. This study aimed to investigate the direct inhibitory effects of XOS on Salmonella Typhimurium colonization and the inductive impairments in gut health and growth performance in broilers. We first probed the inhibitory effects of XOS on S. Typhimurium adhesion and its induction of intestinal epithelial cell (IPEC-J2) injuries. Afterward, 168 one-day-old yellow-feathered broilers were randomly divided into 3 groups (7 replicates/group): negative control (NC, received a basal diet), positive control (PC, received a basal diet with S. Typhimurium challenge) and XOS group (PC birds+1,500 mg/kg XOS). All birds except those in NC were orally challenged with S. Typhimurium from 8 to 10 d of age. Parameters were analyzed on d 11. The results showed that XOS inhibited S. Typhimurium adhesion and the inductive injuries of IPEC-J2 cells by lowering (P < 0.05) certain adhesion-related genes expression of this bacterium. It also alleviated S. Typhimurium-induced increase (P < 0.05) in the expression of certain inflammatory cytokines and tight junction (TJ) proteins of IPEC-J2 cells. Supplementing XOS to S. Typhimurium-challenged broilers attenuated the elevations (P < 0.05) in S. Typhimurium colonization of ileal mucosa and its translocation to the liver and spleen, as well as increased (P < 0.05) certain TJ proteins expression of ileum. Besides, XOS addition normalized S. Typhimurium-induced impairments (P < 0.05) in ileal morphology, final body weight and average daily gain in broilers. Collectively, supplemental XOS directly suppressed intestinal colonization of S. Typhimurium by diminishing its adhesiveness and subsequently mitigated destructions in intestinal barriers, thus contributing to weaken growth retardation in challenged broilers. Our findings provide a new insight into the mechanisms of XOS limiting Salmonella infection in chickens.

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. Individual birds were weighed weekly whereas caecal content was obtained on d 35 from 10 of the individually weighed and cervically dislocated birds. 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.

A circular biorefinery approach for the production of xylooligosaccharides by using mild acid hydrothermal pretreatment of pineapple leaves waste

A hydrothermal process is a sustainable approach for biorefinery leading to conversion of lignocellulosic (LC) biomass into value-added products. This study is based on the production of xylooligosaccharides (XOS) from pineapple leaves (PL) waste by using mild acid like gluconic acid (GA). GA, when used as catalyst in hydrothermal process to produce XOS the yield improved. The above process can be integrated with bacterial cellulose (BC) production bioprocess via Komagataeibacter europaeus 14,148 where gluconic acid is produced as by-product. Maximum XOS (2–5 degree of polymerisation) yield of 67.79 % in the liquid fraction was obtained via hydrothermal treatment at 160 °C for 60 min with 5% gluconic acid concentration. It is based on the selective solubilization of hemicellulose fraction. Enzymatic hydrolysis of GA hydrothermally pretreated solid fraction of PL biomass gave 14.5 g/L glucose with 5% solid loading and 10 FPU/gds enzyme loading which was employed for Bacterial cellulose production.

Effects of cellulose and lignin on xylooligosaccharides production from xylan: The superiority of acetic acid/sodium acetate hydrolysis

Xylooligosaccharides (XOS) are high-value products derived from xylan in lignocellulose and have a variety of prebiotic applications. The intertwining of xylan, cellulose, and lignin in lignocelluloses may affect XOS production. In order to investigate those impacts, the comparative analysis of XOS production was conducted using corncob, poplar and xylan as substrates through the hydrolysis using acetic acid/sodium acetate (AC/SA), acetic acid (AC), and pure water. The results revealed that the hydrolysis of different feedstocks using AC/SA generated the highest XOS yield and the least by-products compared to AC hydrolysis and hydrothermal (HT) treatment. The presence of cellulose led to the reductions of XOS production from xylan by AC/SA hydrolysis, AC hydrolysis, and HT treatment by 6.6%, 6.3%, and 4.3%, respectively. The presence of cellulose and lignin largely decreased XOS yields by 22.2%, 22.0%, and 88.5%, respectively. Obviously, the cellulose slightly inhibited xylan hydrolysis, while lignin had a strong negative effect on xylan hydrolysis. Besides, the adverse effect of lignin on xylan hydrolysis was the greatest in HT treatment. Despite the presence of cellulose and lignin, AC/SA hydrolysis exhibited the superior ability in XOS production and reduced the formation of by-products compared to AC hydrolysis and HT treatment.

Valorization of rice husk by hydrothermal processing to obtain valuable bioproducts: Xylooligosaccharides and Monascus biopigment

Rice husk is a readily available residue which can be used for producing bioproducts in a biorefinery context. In this study, the hemicellulose fraction was hydrolyzed in a hydrothermal process to produce xylooligosaccharides (XOS), whereas the cellulosic hydrolysate was used for red pigment production by Monascus ruber Tieghem IOC 2225. The highest XOS (X2-X4) production (24 g per 1 kg of rice husk) was achieved at 180 °C for 68 min in a non-stirred Parr reactor (50 mL). Subsequently, using a stirred parr reactor (1 L) at 180 °C for 60 min, 40 g of XOS (42% of xylobiose, 35% of xylobiose, 13% of xylotriose, 7% of xylotetraose, and 3% of xylopentaose) per 1 kg of rice husk were obtained. The XOS was then purified by using ultrafiltration (UF) with two diafiltration membranes at 6.5 pH, recovering approximately 92% of total XOS. Further purification was conducted with nanofiltration (NF) at 3.8 pH, recovering approximately 86.4% of XOS in the retentate. This process yielded XOS with a purity of 77%. Additionally, the enzymatic process yielded 132 g/kg of sugar, and the hydrolysate was used to produce 2.1 UA490nm of red pigment by fungi after 7 days.

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-1β 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.

A prebiotic diet modulates the oral microbiome composition and results in the attenuation of oropharyngeal candidiasis in mice.

Oral bacteria can influence the ability of Candida albicans to cause oropharyngeal candidiasis (OPC). We recently reported that a Lactobacillus johnsonii-enriched oral microbiota reduced C. albicans virulence in an immunosuppressed OPC mouse model. As a follow-up, in this work, we aimed to enrich the resident oral Lactobacillus communities with a prebiotic diet to further assess their effect on the severity of OPC. We tested the effect of a prebiotic xylo-oligosaccharides (XOS)-enriched diet in the oral global bacterial composition and severity of OPC. We assessed changes in the oral microbiome composition via 16S-rRNA gene high-throughput sequencing, validated by qPCR. The impact of the prebiotic diet on Candida infection was assessed by quantifying changes in oral fungal and bacterial biomass and scoring tongue lesions. Contrary to expectations, oral Lactobacillus communities were not enriched by the XOS-supplemented diet. Yet, XOS modulated the oral microbiome composition, increasing Bifidobacterium abundance and reducing enterococci and staphylococci. In the OPC model, the XOS diet attenuated Candida virulence and bacterial dysbiosis, increasing lactobacilli and reducing enterococci on the oral mucosa. We conclude that XOS attenuates Candida virulence by promoting a bacterial microbiome structure more resilient to Candida infection. IMPORTANCE This is the first study on the effects of a prebiotic diet on the oral mucosal bacterial microbiome and an oropharyngeal candidiasis (OPC) mouse model. We found that xylo-oligosaccharides change the oral bacterial community composition and attenuate OPC. Our results contribute to the understanding of the impact of the oral bacterial communities on Candida virulence.

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.

Lactic Acid Production from Steam-Exploded Sugarcane Bagasse Using Bacillus coagulans DSM2314

This work aimed at producing lactic acid (LA) from sugarcane bagasse after steam explosion at 195 °C for 7.5 and 15 min. Enzymatic hydrolysis was carried out with Cellic CTec3 and Cellic HTec3 (Novozymes), whereas fermentation was performed with Bacillus coagulans DSM2314. Water washing of pretreated solids before enzymatic hydrolysis improved both hydrolysis and fermentation yields. The presence of xylo-oligosaccharides (XOS) in substrate hydrolysates reduced hydrolysis efficiency, but their effect on fermentation was negligible. The presence of fermentation inhibitors in C5 streams was circumvented by adsorption on activated carbon powder with no detectable sugar losses. High carbohydrates-to-LA conversions (Yp/s) of 0.88 g·g−1 were obtained from enzymatic hydrolysates of water-washed steam-exploded materials that were produced at 195 °C, in 7.5 min, and the use of centrifuged-but-never-washed pretreated solids decreased Yp/s by 16%. However, when the detoxified C5 stream was added at a 10% ratio, Yp/s was raised to 0.93 g·g−1 for an LA productivity of 2.55 g·L−1·h−1. Doubling the pretreatment time caused a decrease in Yp/s to 0.78 g·g−1, but LA productivity was the highest (3.20 g·L−1·h−1). For pretreatment at 195 °C for 7.5 min, the elimination of water washing seemed feasible, but the use of longer pretreatment times made it mandatory to eliminate fermentation inhibitors.

Observation on the ice crystal formation process of large yellow croaker (Pseudosciaena crocea) and the effect of multiple cryoprotectants pre-soaking treatments on frozen quality

By observing the formation behavior of ice crystals, the quality of food products under different freezing conditions can be intuitively judged. In this paper, large yellow croaker was taken as the research object, and a novel cryomicroscopic system was developed to directly observe the structure of ice crystals during the freezing process. The cryoprotective effects of 4% sucrose +4% sorbitol (SU + SO), 4% xylo-oligosaccharide (XO), 4% xylo-oligosaccharide + 0.3% tetrasodium pyrophosphate (XO + TSPP) and 0.2% antifreeze protein (AFP) at different freezing temperatures were investigated. And the evaluation indicators, such as cell deformation degree, equivalent diameters, roundness, elongation and fractal dimension were introduced to quantify the damage of ice crystals to muscle tissues and fibers. The results indicate that reducing the freezing temperature and adding cryoprotectants can improve the quality of large yellow croaker. AFP has the best cryoprotective effect, with a reduction in cell deformation degree of 54.78% and 67.83% compared to the Control group at −5 °C and −20 °C, respectively. SU + SO and XO have the equivalent antifreeze effect, which is slightly inferior to XO + TSPP. In addition, physical parameters of large yellow croaker samples were measured to verify the influence of ice crystal structure on product quality. Therefore, direct observation of the ice crystal formation process and evaluation of ice crystal structure can accurately reflect the quality of frozen products, which is of great significance for the development of refrigeration and preservation technology.

Efficient co-production of xylo-oligosaccharides and fermentable sugars from sugarcane bagasse by glutamic acid pretreatment

In the production of xylo-oligosaccharides (XOS) by organic acid pretreatment, it is often difficult to isolate organic acids from XOS. Here, an acidic amino acid, glutamic acid (GA), was used to pretreat sugarcane bagasse (SCB) to prepare XOS and fermentable sugars. The effects of GA concentration, hydrolysis temperature, and pretreatment time on the yield and polymerization distribution of XOS were investigated. After hydrolysis by 0.2 M GA at 140 °C for 30 min, the maximum yield of X2-5 was 53.3%, and the concentrations of xylose and furfural were 1.8 g/L and 0.1 g/L, respectively. Meanwhile, GA increased the pore size and porosity of SCB as well as the number of functional groups of amino acid residues, which improved the enzymatic efficiency and the maximum yield of glucose was 95.3%. Thus, GA pretreatment provides a more economical, environmentally friendly and sustainable method for the co-production of XOS and glucose from SCB.

Efficient production of xylobiose and xylotriose from corncob by mixed acids and xylanase hydrolysis

Propionic acid (PA) hydrolysis offers a potential pathway for industrial xylooligosaccharide (XOS) production owing to efficiency and simplicity of the process. However, the cost of XOS production needs to be reduced as PA is expensive. This work proposed a strategy of mixed acids hydrolysis, replacing 20% of PA with formic acid (FA), and combined with xylanase hydrolysis to reduce production costs and increase the production of XOS from corncob. The hydrolysis of corncob using mixed FA and PA in a mass ratio of 2:8 produced 61.8% XOS. Xylanase hydrolysis of corncob residue improved XOS yield to 73.1%. Among them, the X2 + X3 yield was as high as 50.6%. Economic evaluation showed that the combined process reduced the XOS production cost by 10.8% compared to PA hydrolysis. The strategy of using FA instead of 20% PA for hydrolysis and enzymatic hydrolysis, with high XOS and monosaccharide yields from corncob, has potential industrial promise.

How Do Prebiotics Affect Human Intestinal Bacteria?-Assessment of Bacterial Growth with Inulin and XOS In Vitro.

Prebiotics are believed to exhibit high specificity in stimulating the growth or activity of a limited number of commensal microorganisms, thereby conferring health benefits to the host. However, the mechanism of action of prebiotics depends on multiple factors, including the composition of an individual's gut microbiota, and is therefore difficult to predict. It is known that different bacteria can utilize inulin and xylooligosaccharides (XOS), but an overview of which bacteria in the human gut may be affected is lacking. Detailed knowledge of how bacterial growth is affected by prebiotics is furthermore useful for the development of new synbiotics, which combine a living microorganism with a selective substrate to confer a health benefit to the host. Hence, we developed a statistical model to compare growth in vitro among typical human gut bacteria from different phylogenetic lineages. Based on continuous observation of the optical density (OD600), we compare maximal growth rates (rmax), maximal attained OD600 (ODmax), and area under the growth curve (AUC) of bacteria grown on inulin or XOS. The consideration of these three parameters suggests strain-specific preferences for inulin or XOS and reveals previously unknown preferences such as Streptococcus salivarius growth on XOS.

Green and efficient fractionation of bamboo biomass via synergistic hydrothermal-alkaline deep eutectic solvents pretreatment: Valorization of carbohydrates

The development of green and efficient pretreatment strategies for renewable biomass valorization is required and remains challenging. In this study, a green, efficient, and profitable pretreatment strategy using hydrothermal combined with alkaline deep eutectic solvents (HT-ADESs) was developed for the fractionation and valorization of bamboo biomass. The results demonstrated that HT pretreatment not only selectively valorized hemicellulose into functional xylooligosaccharides (XOS), accounting for 65.9% of hydrolyzed xylan, but also facilitated the subsequent delignification with ADESs. Furthermore, 29% of hemicellulose was recovered from the prehydrolyzate, revealing a branched structure of O-acetyl-4-O-methyl-glucurono-β-(1 → 4)-ᴅ-xylan. Following delignification with choline chloride/monoethanolamine containing 25 wt% peroxide, up to 98.4% glucose yield and 99.2% xylose yield were realized by enzymatic hydrolysis of pretreated residue, which were significantly higher than those of unpretreated bamboo (14.6% and 8.1%, respectively). The incorporation of an appropriate amount of water or peroxide into pure ADES facilitated lignin fractionation and reduced biorefinery costs. Overall, this work presented a promising pathway that could valorize 1 kg of dry bamboo into 490 g of fermentable sugars and 78 g of XOS, accompanied by 54 g of hemicellulose and 200 g of lignin fractions.

Xylooligosaccharides: A Bibliometric Analysis and Current Advances of This Bioactive Food Chemical as a Potential Product in Biorefineries' Portfolios.

Xylooligosaccharides (XOS) are nondigestible compounds of great interest for food and pharmaceutical industries due to their beneficial prebiotic, antibacterial, antioxidant, and antitumor properties. The market size of XOS is increasing significantly, which makes its production from lignocellulosic biomass an interesting approach to the valorization of the hemicellulose fraction of biomass, which is currently underused. This review comprehensively discusses XOS production from lignocellulosic biomass, aiming at its application in integrated biorefineries. A bibliometric analysis is carried out highlighting the main players in the field. XOS production yields after different biomass pretreatment methods are critically discussed using Microsoft PowerBI® (2.92.706.0) software, which involves screening important trends for decision-making. Enzymatic hydrolysis and the major XOS purification strategies are also explored. Finally, the integration of XOS production into biorefineries, with special attention to economic and environmental aspects, is assessed, providing important information for the implementation of biorefineries containing XOS in their portfolio.

Xylanase Production by Solid-State Fermentation for the Extraction of Xylooligosaccharides from Soybean Hulls§.

The development of a novel process for the production of xylooligosaccharides (XOS) based on the 4R concept is made possible by the integration of numerous techniques, especially enzymatic modification together with the physical pretreatment of renewable materials. This study aims to integrate the use of agricultural wastes for the production of xylanase by a new strain of Penicillium sp. and value-added products, XOS. For the production of xylanase, a solid-state fermentation was performed using wheat bran as substrate. To obtain the most active crude extract of xylanase, the time frame of cultivation was first adjusted. Then, the downstream process for xylanase purification was developed by combining different membrane separation units with size exclusion chromatography. Further characterisation included determination of the optimal pH and temperature, determination of the molecular mass of the purified xylanase and analysis of kinetic parameters. Subsequently, the hydrolytic ability of the partially purified xylanase in the hydrolysis of alkali-extracted hemicellulose from soybean hulls was investigated. Our results show that Penicillium rubens produced extracellular xylanase at a yield of 21 U/g during solid-state fermentation. Using two ultrafiltration membranes of 10 and 3 kDa in combination with size exclusion chromatography, a yield of 49 % and 13-fold purification of xylanase was achieved. The purified xylanase (35 kDa) cleaved linear bonds β-(1→4) in beechwood xylan at a maximum rate of 0.64 μmol/(min·mg) and a Michaelis constant of 44 mg/mL. At pH=6 and 45 °C, the purified xylanase showed its maximum activity. The xylanase produced showed a high ability to hydrolyse the hemicellulose fraction isolated from soybean hulls, as confirmed by thin-layer chromatography. In the hydrothermally pretreated hemicellulose hydrolysate, the content of XOS with different degrees of polymerisation was detected, while in the non-pretreated hemicellulose hydrolysate, the content of xylotriose and glucose was confirmed. Future research focusing on the creation of new enzymatic pathways for use in processes to convert renewable materials into value-added products can draw on our findings.

Broiler chicken response to xylanase and fermentable xylooligosaccharide supplementation

A study was conducted to determine the effect of dietary fiber (DF), xylanase (XYL), xylooligosaccharides (XOS), and a combination of XYL and xylooligosaccharides (STBIO) on chicken growth performance, N-corrected apparent metabolizable energy (AMEn), and nutrient availability, characteristics of the gastrointestinal tract (GIT), and cecal content of short-chain fatty acids (SCFA). A 35-day experiment was performed on 1,920 as hatched Ross 308 broiler chicks, reared in 96 pens and fed ad libitum. Experimental diets were split into 2 phases: starter (0-21 d) and finisher (22-35 d). There were 2 basal diets, first contained 54% maize and in the second, 5% of the maize was replaced by wheat bran as DF. The diets were split into 4 batches: one of them was used as a control, and each of the others were supplemented either with XYL or XOS or with the STBIO. Each diet was fed to 12 pens following randomization. The data were analyzed in GenStat (20th edition) by ANOVA using a 2×4 factorial design. The addition of STBIO improved feed conversion ratio (FCR) and increased weight gain (WG) from 21 to 35 d and from 0 to 35 d (P < 0.05). The inclusion of DF had a negative effect on N and fat retention coefficients at 35 d as well as AMEn and dry matter retention at 21 and 35 d. At 21 d, neutral detergent fiber (NDF) retention was increased when xylanase and STBIO were added to the diet (P < 0.001) and at d 35 the highest retention was noted when the diet was supplemented with DF and XYL or STBIO (P=0.001). There was no dietary effect on jejunum histomorphometry (P > 0.05). The addition of DF increased the concentration of cecal SCFA in particular valeric and propionic acid at 35-day-old birds (P < 0.05). It can be concluded that addition of STBIO in diet could provide benefits in terms of fiber degradation, WG, and feed efficiency.

Induction of plant disease resistance by mixed oligosaccharide elicitors prepared from plant cell wall and crustacean shells.

Basal plant immune responses are activated by the recognition of conserved microbe-associated molecular patterns (MAMPs), or breakdown molecules released from the plants after damage by pathogen penetration, so-called damage-associated molecular patterns (DAMPs). While chitin-oligosaccharide (CHOS), a primary component of fungal cell walls, is most known as MAMP, plant cell wall-derived oligosaccharides, cello-oligosaccharides (COS) from cellulose, and xylo-oligosaccharide (XOS) from hemicellulose are representative DAMPs. In this study, elicitor activities of COS prepared from cotton linters, XOS prepared from corn cobs, and chitin-oligosaccharide (CHOS) from crustacean shells were comparatively investigated. In Arabidopsis, COS, XOS, or CHOS treatment triggered typical defense responses such as reactive oxygen species (ROS) production, phosphorylation of MAP kinases, callose deposition, and activation of the defense-related transcription factor WRKY33 promoter. When COS, XOS, and CHOS were used at concentrations with similar activity in inducing ROS production and callose depositions, CHOS was particularly potent in activating the MAPK kinases and WRKY33 promoters. Among the COS and XOS with different degrees of polymerization, cellotriose and xylotetraose showed the highest activity for the activation of WRKY33 promoter. Gene ontology enrichment analysis of RNAseq data revealed that simultaneous treatment of COS, XOS, and CHOS (oligo-mix) effectively activates plant disease resistance. In practice, treatment with the oligo-mix enhanced the resistance of tomato to powdery mildew, but plant growth was not inhibited but rather tended to be promoted, providing evidence that treatment with the oligo-mix has beneficial effects on improving disease resistance in plants, making them a promising class of compounds for practical application.

Combined iron (III) chloride/sodium citrate with enzymatic hydrolysis for xylo-oligosaccharides and monosaccharides production from poplar

Currently, the production of xylo-oligosaccharides (XOS) from lignocelluloses by chelating system hydrolysis has not been investigated. Herein, iron (III) chloride/sodium citrate (IC/SC) chelating system hydrolysis and xylanase hydrolysis were used to produce XOS from poplar. Then, the delignification of IC/SC-hydrolyzed poplar was performed by p-toluenesulfonic acid (p-TsOH) pretreatment to increase the accessibility of cellulase. The results demonstrated that 42.3% of XOS with an extremely low by-product (xylose/XOS = 0.11) was produced from poplar by 50 mM IC/SC hydrolysis (molar ratio of 1:1, 170 °C, 60 min) and xylanase hydrolysis. The second step IC/SC hydrolysis and xylanase hydrolysis of poplar increased the yield of XOS to 51.3%. Finally, the glucose yield of p-TsOH-pretreated poplar (60% p-TsOH, 70 °C, 30 min) was greatly increased from 37.5% to 83.8% by cellulase hydrolysis with Tween 80 addition. The novel strategy proposed in this work was feasible for XOS and monosaccharides production from poplar.

Coproduction of xylooligosaccharides, glucose, and less-condensed lignin from sugarcane bagasse using syringic acid pretreatment

Current strategies for the production of xylooligosaccharides (XOS) from biomass through non–enzymatic catalysis often led to a certain degree of lignin condensation, which severely restrains subsequent enzyme hydrolysis of cellulose. Herein, syringic acid (SA) pretreatment was investigated to coproduce XOS, glucose, and less-condensed lignin from sugarcane bagasse. SA acted as a catalyst and lignin condensation inhibitor during the pretreatment. The highest XOS yield of 58.7% (27.7% xylobiose and 24.7% xylotriose) was obtained at 180 °C − 20 min − 9% SA, and the corresponding xylose/XOS ratio was only 0.42. Compared with the pretreatment at 180 °C − 20 min − 0% SA, the addition of 9% SA increased the glucose yield from 85.7% to 92.4% and decreased the degree of lignin condensation from 0.55 to 0.42. Moreover, 26.7% of SA could be easily recovered. This work presents a pretreatment strategy in which the efficient production of XOS and the suppression of lignin condensation are achieved simultaneously.