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Acetylxylan esterases (AXEs) are essential enzymes that break down the acetyl groups in acetylated xylan found in plant cell walls polysaccharides. They work synergistically with backbone-depolymerizing xylanolytic enzymes to accelerate the degradation of complex polysaccharides. In this study, we cloned the gene axeA , which encodes the acetylxylan esterase from Aspergillus nidulans FGSC A4 (AxeAN), into the pEXPYR expression vector and introduced it into the high protein-producing strain A. nidulans A773. The purified AxeAN, with a molecular weight of 33.5 kDa as confirmed by SDS-PAGE, was found to be active on ρ -nitrophenyl acetate (ρ NPA), exhibiting a remarkably high specific activity (170 U mg−1) at pH 7.0 and 55 °C. AxeAN demonstrated stability over a wide pH range (5.5–9.0), retaining >80% of its initial activity after 24 h. The K M and V max were 0.098 mmol L−1 and 320 U mg−1, respectively, using ρ NPA as a substrate. We also evaluated the synergistic effect of AxeAN with an endo-1,4-β-xylanase from Malbranchea pulchella (MpXyn10) in the hydrolysis of four different xylans (Birchwood, Beechwood, Oat spelt, and Arabinoxylan) to produce xylooligosaccharides (XOS). The best results were obtained using Birchwood xylan as substrate and MpXyn10-AxeAN as biocatalysts after 24 h of reaction (50 °C), with a XOS-yield of 91%, value 41% higher when compared to MpXyn10 (XOS-yield of 63%). These findings showed the potential of the application of AxeAN, together with other xylanases, to produce xylooligosaccharides with high purity and other products with high added value in the field of lignocellulosic biorefinery. [ABSTRACT FROM AUTHOR]

We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C. Hydrolysates with high content of lower molecular weight oligomeric sugars were obtained using LFC, and were considered advantageous for application as prebiotics. These results are attributed to the complementary features of acetic acid and furfural contained within the LFC. Computational simulation using Aspen Plus was used to investigate the effects of recycling on LFC, and it demonstrated the feasibility of the catalyst-recirculating system. A validation study was conducted based on simulation results to predict the actual performance of the proposed pretreatment system. Based on these results, the recirculating system was predicted to improve the conversion yield and low-molecular weight oligomers yield by 1.5-fold and 1.6-fold, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

Xylooligosaccharides (XOs) have shown high potential as prebiotics with nutritional and health benefits. In this work, XOs were obtained from highly purified, carboxy-reduced glucuronoarabinoxylans by treatment with Driselase®. The mixtures were fractionated, and the structures were elucidated by methylation analysis and NMR spectroscopy. Antioxidant activity was determined by the methods of DPPH and β-carotene/linoleic acid. It was found that the most active oligosaccharides (P3 and G3) comprised 4 or 5 xylose units, plus two arabinoses and one 4- O -methylglucose as side chains, their sequence of units was determined. The optimal concentration for their use as antioxidants was 2 mg/mL. The synthetic antioxidant butylated hydroxytoluene (BHT, 0.2 mg/mL) showed a percentage of inhibition 15% higher than P3. Although its concentration was ∼10 times higher, P3 is non-toxic, and could have great advantages as food additive. These results show that pure XOs exert significant antioxidant activity, only due to their carbohydrate nature. • XOs were obtained from reduced glucuronoarabinoxylans by treatment with Driselase®. • The XOs mixture was fractionated by GPC on BioGel P-2 to give pure XOs. • Antioxidant activity was measured by DPPH and β-carotene/linoleic acid. • The most active XOs had 4 or 5 xylose units, arabinose, and 4- O -methylglucose. [ABSTRACT FROM AUTHOR]

To date, although the high-carbohydrate (HC) feed has been extensively adopted in the aquaculture industry, its effects on the intestinal function and development of aquatic animals still remain unclear. In addition, the corresponding nutritional intervention is still barely reported. This study aimed to evaluate the influence of xylooligosaccharides (XOS) on the intestinal health of Megalobrama amblycephala subjected to a HC feeding. Fish (average weight: 44.55 ± 0.15 g) were randomly offered 3 diets, including a control one (29 % carbohydrate), a HC one (41 % carbohydrate), and a XOS supplemented one (HC + 1.0 % XOS, HCX) respectively for 12 weeks. The HC feeding caused morphological abnormalities of intestine, an increased intestinal permeability, and the intestinal immunosuppression, all of which were markedly reversed by XOS administration. In addition, compared with the HC group, HCX feeding remarkably promoted the intestinal activities of digestive and brush border enzymes, and the expressions of cell proliferation-related proteins (Wnt10b and Cyclin D1). The 16s rDNA sequencing also revealed that XOS administration increased the abundance of beneficial bacteria, and decreased that of pathogenic ones. In conclusion, dietary supplementation of XOS improved the intestinal histomorphology, barrier function, cell proliferation and bacterial communities of carbohydrate-overloaded fish Megalobrama amblycephala. • High-carbohydrate diet impairs intestinal mucosal immune function in fish. • High-carbohydrate diet increases intestinal permeability. • XOS stimulates the growth of SCFAs-producing bacteria in the intestine. • XOS promotes intestinal development by triggering the Wnt/β-catenin pathway. [ABSTRACT FROM AUTHOR]

Deep eutectic solvent (DES) pretreatment was applied to corncob to obtain xylooligosaccharides (XOS) by enzymatic hydrolysis using xylanase. Based on the XOS titers in the hydrolysate, urea was the most effective among the hydrogen bond donors tested to couple choline chloride (ChCl). DES pretreatment at 130 °C for two hours with ChCl-Urea (molar ratio of 1:2) containing 40 % water, decreased lignin fraction from 12.8 % to 6.9 %, while 79 % of the xylan was retained in the pretreated corncob. The highest XOS production was obtained using 400 U/g xylanase at 60 °C, which yielded 12.0 g/L XOS with a low degree of polymerization (LDP-XOS). The total XOS yield based on the raw corncob was calculated as 14.4 %, 90 % of which was LDP-XOS. The cellulose-rich residual biomass could be hydrolyzed enzymatically to glucose with 65 % cellulose digestibility. The discarded biomass after hydrolyzes was 21.7 % of the raw material. The results showed that DES was a promising pretreatment for enhancing enzymatic XOS production. [Display omitted] • DES based process was developed for enzymatic XOS production from corncob. • Urea was the most efficient H bond donor to couple choline chloride. • DES reduced the lignin content from 12.8 % to 6.9 %. • Xylan in the pretreated corncob was open to enzymatic hydrolysis. • Xylooligosaccharide yield based on the raw corncob was 14.4 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanofiltration of Beechwood-derived xylooligosaccharides (XOS) by ceramic membranes. • XOS mixtures separated into low, medium and high degrees of polymerization (DP). • Pressure and pH significantly impact nanofiltration selectivity by DP for XOS. • SANS results indicate that higher XOS concentrations magnify their aggregation. The biotechnological and functional food applications of xylooligosaccharides (XOS) are determined by their degree of polymerisation (DP) and their substituents' characteristics. Separation of XOS presents a formidable challenge for their large-scale production due to their complexity and similarity. This study employs nanofiltration membranes to fractionate beechwood xylan hydrolysates containing XOS. Tubular ceramic membranes with molecular weight cut-offs of 750, 450, and 200 Da effectively separated XOS into three distinct DP ranges, namely X2-X5, X2-X4, and X2-X3. The impacts of operating pressure and pH were evaluated to find the conditions leading to high permeate flux while maintaining high selectivity. Operating pressure of 10 bar with pH 7.0 for the 750 and 450 Da membranes and pH 4.2 for the 200 Da membrane yielded purities of 85%, 71%, and 74% for X2-X5, X2-X4, and X2-X3, respectively. [ABSTRACT FROM AUTHOR]

Arabinoxylan is a major hemicellulose in the sugarcane plant cell wall with arabinose decorations that impose steric restrictions on the activity of xylanases against this substrate. Enzymatic removal of the decorations by arabinofuranosidases can allow a more efficient arabinoxylan degradation by xylanases. Here we produced and characterized a recombinant Bifidobacterium longum arabinofuranosidase from glycoside hydrolase family 43 (Bl Abf43) and applied it, together with GH10 and GH11 xylanases, to produce xylooligosaccharides (XOS) from wheat arabinoxylan and alkali pretreated sugarcane bagasse. The enzyme synergistically enhanced XOS production by GH10 and GH11 xylanases, being particularly efficient in combination with the latter family of enzymes, with a degree of synergism of 1.7. We also demonstrated that the enzyme is capable of not only removing arabinose decorations from the arabinoxylan and from the non-reducing end of the oligomeric substrates, but also hydrolyzing the xylan backbone yielding mostly xylobiose and xylose in particular cases. Structural studies of Bl Abf43 shed light on the molecular basis of the substrate recognition and allowed hypothesizing on the structural reasons of its multifunctionality. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of lignocellulose biomass (LCB) based platform chemicals and other byproducts has become imperative in order to reduce global carbon footprints and maximise utilization of renewable energy sources. LCB derived xylan is an abundantly accessible feedstock that can be subjected to pretreatment and enzymatic bioconversion using microbe-derived xylanolytic secretomes. The enzymatic breakdown of xylan into xylooligosaccharides (XOS) and xylose requires synergistic action of xylanases and other debranching enzymes. XOS, being short chain oligosaccharides, act as substrates to establish the commensal microbiome in the lower gut of animals and exhibit prebiotic properties. Further, D-xylose, a pentose sugar, obtained from xylan hydrolysis can be converted into xylitol (C 5 H 12 O 5) which is widely used in food and pharmaceutical industries as an alternative sweetener. The researchers have extensively reviewed cellulose-based biorefineries that focus on integrated product generation. However, valorization of hemicellulosic xylan extracted from agricultural biomass to generate industrially relevant products requires a comprehensive analysis. This article, therefore, highlights sustainable operations using LCB for the production of xylanolytic enzymes, xylooligosaccharides and xylitol. Insights into knowledge gaps and technological challenges have been discussed with a focus on enzymatic hydrolysis of LCB xylan and multi-product framework from a biorefinery standpoint. [Display omitted] • Enzymatic extraction of hemicellulosic fraction from lignocellulosic biomass. • Hydrolysis of xylan into xylooligosaccharides using xylanolytic enzyme complex. • Detoxification of hemicellulosic hydrolysate and production of xylitol. • Integration of xylanase, xylooligosaccharide and xylitol bioproduction from a biorefinery standpoint. [ABSTRACT FROM AUTHOR]

The experiment was to investigate the effect of synbiotics instead of antibiotics on growth performance and cecal microbial flora structure of weaned New Zealand meat rabbits. A total of 300 35-day-old weaning New Zealand meat rabbits were selected and randomly divided into three groups, with five replicates in each group and 20 rabbits in each replicate. The rabbits in control group were fed with basal diet, the rabbits in antibiotic group were fed with basal diet supplement with oxytetracycline, and the rabbits in synbiotic group were fed with basal diet supplement with 0.04% synbiotic (by Bacillus subtilis, Bacillus coagulans and xylooligosaccharides), the experimental period was 42 d. The results showed that compared with antibiotic group and control group, the average daily gain, average daily feed intake and survival rate of meat rabbits in synbiotic group were significantly increased (P<0.05), and the diarrhea rate was significantly decreased (P<0.05). In cecal microflora of meat rabbits in vegetarian group, the relative abundance of Desulfobacterota, Actinobacteriota, Desulfovibrionia, Barnesiellaceae, Alistipes and Lachnospiraceae_NK4A136_group was significantly increased (P<0.05), and the relative abundance of Proteobacteria and Gammaproteobacteria was significantly decreased (P<0.05). The microbial flora structure was better than that of antibiotic group and control group. The experiment indicates that synbiotics have significant effect in promoting growth and maintaining intestinal microecological balance in meat rabbits, which have the potential to replace antibiotics. [ABSTRACT FROM AUTHOR]

As the emerging functional food additives, xylooligosaccharides are receiving high commercial interest due to their excellent gut microbiota modulation capacity, and accumulating studies have suggested that acidic hydrolysis for xylooligosaccharides preparation is the most convenient and cost-effective approach, whereas liquid acids are still limited due to the challenges in acid catalysts separation and products recovery. In the present study, a strong acidic cationic resin (NKC-9), as a recyclable solid acid catalyst, was successfully applied to xylooligosaccharides production by acidic hydrolysis of xylan. Additionally, a central composite design with response surface methodology was employed to optimize the conditions for maximizing xylooligosaccharides yields. The results suggested that xylooligosaccharides with the desired degree of polymerization (2–6) could be prepared, and the maximum yield was reached 47.7% in the case of 5% solid acid loading at 131 °C for 42 min. Finally, the recyclability of the solid acid catalysts confirmed that it was a cost-effective strategy for xylooligosaccharides production. [ABSTRACT FROM AUTHOR]

Xylanases have a broad range of applications in agro-industrial processes. In this study, we report on the discovery and characterization of a new thermotolerant GH10 xylanase from Bacillus safensis, designated as BsXyn10. The xylanase gene (bsxyn10) was cloned from Bacillus safensis and expressed in Escherichia coli. The reduced molecular mass of BsXyn10 was 48 kDa upon SDS-PAGE. Bsxyn10 was optimally active at pH 7.0 and 60 °C, stable over a broad range of pH (5.0–8.0), and also revealed tolerance toward different modulators (metal cations, EDTA). The enzyme was active toward various xylans with no activity on the glucose-based polysaccharides. KM, vmax, and kcat for oat spelt xylan hydrolysis were found to be 1.96 g·L−1, 58.6 μmole·min−1·(mg protein)−1, and 49 s−1, respectively. Thermodynamic parameters for oat spelt xylan hydrolysis at 60 °C were ΔS* = −61.9 J·mol−1·K−1, ΔH* = 37.0 kJ·mol−1 and ΔG* = 57.6 kJ·mol−1. BsXyn10 retained high levels of activity at temperatures up to 60 °C. The thermodynamic parameters (ΔH*D, ΔG*D, ΔS*D) for the thermal deactivation of BsXyn10 at a temperature range of 40–80 °C were: 192.5 ≤ ΔH*D ≤ 192.8 kJ·mol−1, 262.1 ≤ ΔS*D ≤ 265.8 J·mol−1·K−1, and 99.9 ≤ ΔG*D ≤ 109.6 kJ·mol−1. The BsXyn10-treated oat spelt xylan manifested the catalytic release of xylooligosaccharides of 2–6 DP, suggesting that BsXyn10 represents a promising candidate biocatalyst appropriate for several biotechnological applications. [ABSTRACT FROM AUTHOR]

Xylooligosaccharides are known prebiotics that various foods and feed industries can utilize. In the present study, the xylan was extracted from sugarcane bagasse and coconut coir by NaOH treatment and it was further structurally characterized by FTIR. Furthermore, Thermomyces lanuginosus VAPS-24 was used to produce endo-xylanase, which induced the production of XOS from both of these substrates. The maximum production of XOS in 8 h using 20U enzyme concentration and 2% substrate concentration was found as 10.10 mg/ml, 5.43 mg/ml for sugarcane bagasse and coconut coir, respectively. Further, the produced XOS was structurally characterized by the NMR, HPLC and FTIR analysis. This study gives a clue that the sugarcane bagasse can be used as the potent producer for the xylooligosaccharides as compared to the coconut coir and can be utilized at the industrial level. [ABSTRACT FROM AUTHOR]

In recent decades, consumer preference and attention to foodstuff presented as healthy and with desirable nutritional information, has increased significantly. In this field, the meat industry has a challenging task since meat and meat products have been related to various chronic diseases. Functional ingredients have emerged in response to the increasing demand for healthier and more nutritious foods. On this matter, oligosaccharides such as fructooligosaccharides (FOS), xylooligosaccharides (XOS), galactooligosaccharides (GOS), and chitooligosaccharides (COS) have been presented as suitable ingredients for the meat industry with the aim of obtaining healthier meat derivatives (e.g. with low fat or sugar content, reduced amount of additives, and desirable functional properties, etc.). However, studies considering application of such oligomers in the meat sector are scarce. In addition, a large number of issues remain to be solved related both to obtaining and characterizing the oligosaccharides available in the industry and to the effect that these ingredients have on the features of meat products (mainly physicochemical and sensory). The study of new oligosaccharides, the methodologies for obtaining them, and their application to new meat products should be promoted, as well as improving knowledge about their effects on the properties of functional meat foods. [ABSTRACT FROM AUTHOR]

Xylanase enzymes are useful to fractionate plant biomass, producing xylan, xylooligosaccharides (XOS), and antioxidant-derived XOS. In a biorefinery, pretreated biomass can be digested with xylanase prior to cellulose saccharification, enhancing the product portfolio in the process. With this vision, this study highlighted a wide range of new products attainable from alkaline-sulfite–pretreated sugarcane bagasse by treatments with endo-xylanase under controlled conditions. The developed process provided a crude extract corresponding to 29.7% (w/w) of pretreated sugarcane bagasse. The crude extract included a relatively polymeric glucuronoarabinoxylan fraction, DP2-DP6 xylooligosaccharides, and aromatic compounds. The enzymatically produced extract was fractionated with increasing ethanol concentrations [up to 90% (v/v)], providing precipitation of varied polymeric xylan fractions (48% (w/w) of the crude extract) with average molar masses ranging from 28 kDa to 3.6 kDa. The fraction soluble in 90% ethanol was subjected to adsorption on 4% (w/v) activated charcoal and eluted with an ethanol gradient from 10% to 70% (v/v), thus providing xylooligosaccharides and aromatic fractions. Most of the xylooligosaccharides (74% of the eluted sugars) were washed out in 10%–30% ethanol. DP2 and DP3 structures predominated in the 10% ethanol fraction, while DP5 structures were significantly enriched in the 30% ethanol fraction. Higher ethanol concentrations desorbed xylooligosaccharides associated with higher amounts of aromatic compounds. Total aromatics, phenolic structures, and p-hydroxycinnamates predominated in the fractions desorbed with 60% and 70% ethanol. The antioxidant activity of produced fractions correlated with their phenolic contents. Compiled results indicate that a wide variety of products can be prepared from pretreated biomass using xylanase-aided extraction procedures. Recovered fractions presented different features and specific application prospects. Beyond polymeric xylan with low lignin contamination, xylooligosaccharides or even lignin-carbohydrate complexes with antioxidant activity can be included in the biorefinery portfolio based on the currently developed fractionation studies.

Xylanases are industrial enzymes with multiple applications in the food, pharmaceuticals, bio-bleaching, and textiles industries. The present study explores a putative novel bacterium Paenibacillus sp. PCH8 shows xylanolytic activity from Himalayan glacial soil. Genome sequencing and analysis revealed multiple genes encoding xylanases, cellulases, and other lignocellulolytic enzymes. The bacterium utilized oat spelt xylan substrate and showed xylanolytic activity in wide pH (4.0 – 12.0) and temperature (4 to 90 ºC). Proteomic analysis revealed 1,4-β-xylanase, arabinan endo-1,5-α-l-arabinosidase, and 11 hypothetical proteins in partially purified protein fraction. Multi-substrate enzymatic activity (IU/mg) was observed for beechwood (21.42), oat spelt xylan (19.8), CMC (5.17), avicel (7.7), and starch (1.62) in protein fraction. The hydrolysis of xylan led to the formation of xylose, xylobiose, xylotriose, and xylotetraose upon analysis by LC-MS. The xylooligosaccharides (XOS) containing hydrolysate enhanced the growth of probiotic microbes, suggesting prebiotic potential. Thus, the study provides a new source of xylanases from Paenibacillus sp. PCH8, with potential applications in lignocellulosic biomass hydrolysis and XOS production.

Abstract The capacity of different Bacillus species to produce large amounts of extracellular enzymes and ability to ferment various substrates at a wide range of pH and temperature has placed them among the most promising hosts for the industrial production of many improved and novel products. The global interest in prebiotics, for example, xylooligosaccharides (XOs) is ever increasing, rousing the quest for various forms with expanded productivity. This article provides an overview of xylanase producing bacilli, with more emphasis on their capacity to be used in the production of the XOs, followed by the purification strategies, characteristics and application of XOs from bacilli. The large-scale production of XOs is carried out from a number of xylan-rich lignocellulosic materials by chemical or enzymatic hydrolysis followed by purification through chromatography, vacuum evaporation, solvent extraction or membrane separation methods. Utilization of XOs in the production of functional products as food ingredients brings well-being to individuals by improving defense system and eliminating pathogens. In addition to the effects related to health, a variety of other biological impacts have also been discussed.

Abstract Background Pretreatment is the key step for utilizing lignocellulosic biomass, which can extract cellulose from lignin and disrupt its recalcitrant crystalline structure to allow much more effective enzymatic hydrolysis; and organic acids pretreatment with dual benefic for generating xylooligosaccharides and boosting enzymatic hydrolysis has been widely used in adding values to lignocellulose materials. In this work, furoic acid, a novel recyclable organic acid as catalyst, was employed to pretreat sugarcane bagasse to recover the xylooligosaccharides fraction from hemicellulose and boost the subsequent cellulose saccharification. Results The FA-assisted hydrolysis of sugarcane bagasse using 3% furoic acid at 170 °C for 15 min resulted in the highest xylooligosaccharides yield of 45.6%; subsequently, 83.1 g/L of glucose was harvested by a fed-batch operation with a solid loading of 15%. Overall, a total of 120 g of xylooligosaccharides and 335 g glucose could be collected from 1000 g sugarcane bagasse starting from the furoic acid pretreatment. Furthermore, furoic acid can be easily recovered by cooling crystallization. Conclusion This work put forward a novel furoic acid pretreatment method to convert sugarcane bagasse into xylooligosaccharides and glucose, which provides a strategy that the sugar and nutraceutical industries can be used to reduce the production cost. The developed process showed that the yields of xylooligosaccharides and byproducts were controllable by shortening the reaction time; meanwhile, the recyclability of furoic acid also can potentially reduce the pretreatment cost and potentially replace the traditional mineral acids pretreatment.

Endoxylanases active under extreme conditions of temperature and alkalinity can replace the use of highly pollutant chemicals in the pulp and paper industry. Searching for enzymes with these properties, we carried out a comprehensive bioinformatics study of the GH10 family. The phylogenetic analysis allowed the construction of a radial cladogram in which protein sequences putatively ascribed as thermophilic and alkaliphilic appeared grouped in a well-defined region of the cladogram, designated TAK Cluster. One among five TAK sequences selected for experimental analysis (Xyn11) showed extraordinary xylanolytic activity under simultaneous conditions of high temperature (90 °C) and alkalinity (pH 10.5). Addition of a carbohydrate binding domain (CBM2) at the C-terminus of the protein sequence further improved the activity of the enzyme at high pH. Xyn11 structure, which has been solved at 1.8 Å resolution by X-ray crystallography, reveals an unusually high number of hydrophobic, ionic and hydrogen bond atomic interactions that could account for the enzyme’s extremophilic nature.

The increasing use of non-renewable resources and its continuous depletion has become a major concern nowadays. The production of renewable fuels from agricultural lignocellulose waste is sustainable and economically feasible. Sugarcane top is one of the most abundant lignocellulosic biomasses in India. More conveniently, it is burned in the field being in large quantity and the high-cost involved in its collection and transportation. The pretreatment process is one of the cost intensive steps in the bioethanol production, owing to the manpower and expensive chemicals requirement to separate cellulose, hemicellulose and lignin from lignocellulosic biomass. In recent times, the advent of novel recombinant carbohydrate-active enzymes from different microbial sources by genetic manipulation has led to great advances in saccharification of pretreated biomass leading to higher production of bioethanol. The multi-enzyme complexes called cellulosomes are capable of hydrolyzing cellulose and hemicellulose. This study is aimed at production of xylan, bioethanol and other value-added products from sugarcane tops. Isolation, separation and characterization of xylan, cellulose and lignin from sugarcane tops can be most efficient industry oriented approach due to their xylo-oligosaccharides or alternative substrate, bioethanol and oil based petro-chemical applications. The saccharified hydrolysate can be used for bioethanol production by fermenting with Saccharomyces cerevisiae. Xylooligosaccharides can also be produced by enzymatic hydrolysis of xylan extracted from agro-waste and have applications in controlling blood sugar level, boosting immunity, improving intestinal function and reducing fatigue. Xylan can be utilized for the production of xylo-oligosaccharides, food coating, packaging films and other pharmaceutical applications. Lignin is mainly used as a rubber intensifier, polyolefin and rubber packing. It is also used in making cement, composite materials, unsaturated polyester and vinyl ester as filler and co-monomer.

We report the adsorption equilibrium, kinetics and thermodynamic studies of endo-1,4-β-D-xylanase adsorption onto ordered mesoporous matrices of silica, carbon, and zirconia. Rapid adsorption of the enzyme was observed within 5 min, and the equilibrium was attained in 60 min. The adsorption profiles were fitted to a pseudo-second-order kinetic equation indicating a tendency towards chemisorption and that the kinetics improved with temperature. Besides, it was found that the adsorption equilibrium data followed a typical Langmuir model and that the activation energy was determined using the Arrhenius equation. Likewise, the computed thermodynamic parameters revealed that the adsorption is favourable, spontaneous, and endothermic.

Whey beverages that were enriched with fructooligosaccharides (FOS) and xylooligosaccharides (XOS) were used for carrying Foeniculum vulgare extract that was obtained by the supercritical CO2 extraction technique to produce novel functional products. Fennel-based whey beverages were subjected to thermosonication processing (100, 200, and 300 W at 60 °C for 15 min) to verify the performance of the dairy colloidal system for protecting the bioactive fennel compounds. The impacts of thermosonication processing on the quality attributes of the functional whey beverages were examined according to their droplet size distribution, microstructure, kinetic stability, color parameters, browning index, total phenolic content (TPC), and antioxidant capacity by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2-Azino-bis-(3-ethylbenzothiazoline)-6-sulphonic acid) assays. The enrichment of the whey beverages with FOS and XOS did not affect their kinetic stability. However, the addition of prebiotic dietary fibers contributed to reducing the mean droplet size due to the formation of whey protein–FOS/XOS conjugates. The thermosonication treatments did not promote color changes that were discernible to the human eye. On the other hand, the thermosonication processing reduced the kinetic stability of the beverages. Overall, the colloidal dairy systems preserved the antioxidant capacity of the fennel seed extract, regardless of thermosonication treatment intensity. The whey beverages enriched with FOS and XOS proved to be effective carrying matrices for protecting the lipophilic bioactive fennel compounds. [ABSTRACT FROM AUTHOR]

Simple Summary: Naw Mai Dong is an ethnic fermented bamboo shoot product that is popular in the upper northern region of Thailand. Xylan is a component of hemicellulose that can be found in bamboo shoots. It is a raw material utilized in xylooligosaccharide production. To produce Naw Mai Dong, bamboo shoots are sliced and pickled in bottles or jars that contain water rinsed from rice crops with or without salt. This would differ from the simple brine comprised of water and salt that is associated with most other pickled products. Naw Mai Dong is sour due to its acidity. Importantly, fermented fruits and vegetables are a potential source of lactic acid bacteria, which have been well-documented to possess a number of probiotic characteristics. This would imply that some of the lactic acid bacteria present during bamboo shoot fermentation could serve as efficient xylooligosaccharides-fermenting probiotic lactic acid bacteria. Xylooligosaccharides (XOSs) are produced from xylan, which is a component of the hemicellulose that can be found in bamboo shoots. Naw Mai Dong, an ethnic pickled bamboo shoot product of northern Thailand, is generally characterized as acidic and has a sour taste. It can be considered a potential source of probiotic lactic acid bacteria (LAB). This study aimed to isolate efficient XOSs-fermenting probiotic LAB from ethnic pickled bamboo shoot products. A total of 51 XOSs-fermenting LAB were recovered from 24 samples of Naw Mai Dong, while 17 strains exhibited luxuriant growth in xylose and XOSs. Among these, seven strains belonging to Levicaseibacillus brevis and Pediococcus acidilactici exhibited similar growth in glucose, xylose, and XOSs, while the rest showed a weaker degree of growth in xylose and XOSs than glucose. Sixteen strains exhibited resistance under gastrointestinal tract conditions and displayed antimicrobial activity against foodborne pathogens. Notably, Lv. brevis FS2.1 possessed the greatest probiotic properties, with the highest %hydrophobicity index and %auto-aggregation. Effective degradation and utilization of XOSs by probiotic strains are dependent upon xylanase and β-xylosidase production, as well as xylose metabolism. It can be concluded that pickled bamboo shoot products can be a beneficial source of XOSs-fermenting probiotic LAB. [ABSTRACT FROM AUTHOR]

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Brewers' spent grains (BSGs) represent the largest quantity of solid waste from brewing, while xylooligosaccharides (XOS) produced from BSG show promising applications in food, beverage and health products. Production of XOS from a Weiss and malt BSG was scaled-up in steam explosion hydrothermal treatment using process conditions from bench-scale liquid hot water optimisations in stirred batch reactors. Three levels of moisture (15, 25 and 32% dry matter) achieved by screw press dewatering were evaluated by varying the treatment temperatures and times. Results show the highest XOS yields (> 73.1%) were obtained, for both BSGs, at process condition selected (180 °C, 10 min) with 25% initial dry matter content. These yields were higher than reported bench-scale optimisations (61%), but obtained using 60% less water; hence, initial dry matter content was an important variable affecting XOS yield. The pilot-scale steam explosion results provide a departing point for a cost-effective commercial production of XOS from BSG. [ABSTRACT FROM AUTHOR]

Natural compounds have been used to regulate numerous metabolic dysfunctions such as obesity, diabetes, and dyslipidaemia. Xylan oligosaccharides (XOS) alleviate obesity, diabetes, and dyslipidaemia via the regulation of glucose and lipid metabolisms, and the modification of gut microbiota. Moreover, XOS is also shown to inhibit obesity, diabetes, and related metabolic disorders such as inflammation and oxidative stress, by regulating the related genes and enzymes that contribute to the respective disorders. The information currently available does not offer in-depth elucidation regarding the molecular mechanisms of action of XOS in controlling obesity, diabetes, and related metabolic disorders, thus remain to be elucidated. The present review discusses XOS and its mechanisms of action, and key roles in regulating obesity, diabetes, and related metabolic disorders, highlighting the potential use of this compound in the improvement of novel therapeutic approaches for the treatment of the aforementioned diseases. [ABSTRACT FROM AUTHOR]

Increasing the yields of short xylooligosaccharides by enzymatic production is efficient to improve prebiotic effects. Previously, C-terminal oligopeptide C60 was found to accelerate short xylooligosaccharides. Herein, in order to further understand the molecular mechanism of C60, the sequence analysis firstly showed that C60 displays typical properties of a linker (rich in proline/alanine/glycine/glutamine/arginine, 8.33–20.00%). C60 shared the highest identity with the N-terminal region of esterase (98.33%) and high identity with the linker between xylanase and esterase from Prevotella sp. (56.50%), it is speculated to originate from an early linker between XynA and another domain. Besides, structure simulation showed that C60 enhances the molecular interactions between substrate and active residues to improve catalytic efficiency. Moreover, three truncated variants with different lengths of C-terminal regions were successfully generated in Escherichia coli. The specific activities of variants were 6.44–10.24 fold of that of XynA-Tr, and their optimal temperature and pH were the same as XynA-Tr. Three truncated variants released more xylooligosaccharides, especially xylobiose (46.33, 43.41, and 49.60%), than XynA-Tr (32.43%). These results are helpful to understand the molecular mechanism of C60, and also provide new insight to improve the yields of short xylooligosaccharides by molecular modification at the terminal of xylanases. [ABSTRACT FROM AUTHOR]

A kinetic study was performed to determine the kinetics of hemicellulose (xylan) hydrolysis during subcritical hydrothermal pretreatment of OPFPF. The trend of xylan conversion was observed over 40-min treatment time at two different conditions: without CO2 addition at four different temperatures (170, 180, 190, and 200 °C), and with CO2 addition of 0.5 and 1 MPa at 180 °C. Experimental data obtained was subsequently fitted into the selected first-order kinetic model. It was demonstrated that the experimental data was comparable to the predicted values, indicating the suitability of the chosen model for quantitative interpretation of the experimental results. In addition, the reaction rate was found to improve with the rise of temperature and the presence of CO2, as indicated by the increasing values of reaction rate constants, k. The relationship between k and temperature was successfully established through Arrhenius equation, where the activation energies for xylan conversion were found in the range of 43.49 to 170.16 kJ/mol. Based on the results, subcritical pretreatment of OPFPF at 180 °C and 0.5 MPa CO2 was suggested suitable for high glucose recovery from OPFPF due to high xylan removal rate and low generation of hydrolysis byproduct which is beneficial for successful saccharification and fermentation. This study provides knowledge in the kinetics of xylan autohydrolysis in oil palm frond, and hence could contribute in the process design for recovery of glucose and hemicellulose derivatives such as XOS and furfural from oil palm residues. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is an important resource for biofuels, chemicals, and bioproducts; however, deconstructing its recalcitrant structure is a challenge. In this study, controlled instant pressure drop (DIC)-assisted alkaline pretreatment process of poppy capsule waste (PCW) was developed and statistically optimized with the aim of enhanced fractionation efficiency and production of fermentable sugars and xylooligosaccharides (XOs). The effects of DIC process variables on PCW fractionation were investigated. The optimal DIC conditions were found as 5 bar vapor pressure, 540 s processing time, and 9% (w/w) moisture content. At the second stage, optimum conditions for alkaline extraction were found as 22.58% (w/w) KOH, 1-h extraction time, and 22.15 mL precipitant volume. Process optimization concluded a hemicellulose separation yield of 26.37±0.08%, corresponding to 104.7% increase. Process optimization also contributed to the sustainability of the process by reducing KOH and precipitant consumption by 9.7% and 11.4%, respectively, with a concurrent shortening of the processing time from 24 to 1 h. DIC pretreatment enhanced the enzymatic hydrolysis yield of PCW, and a maximum glucan-to-glucose conversion yield of 22.85±0.74% was obtained, which corresponds to a 9-fold increase. Hydrolysis of PCW and hemicellulose-rich fraction by xylanase yielded xylose-free xylobiose (X2) as the principal product. SEM analysis demonstrated the expansion of PCW structure by DIC pretreatment, reasoning the higher fractionation efficiency and enzymatic hydrolysis yields. The optimized process could be an efficient option for lignocellulose fractionation, enzymatic saccharification, and XOs production within biorefinery concept while reducing the requirement for chemicals and processing time. [ABSTRACT FROM AUTHOR]

Abstract Background Xylanases are one of the most extensively used enzymes for biomass digestion. However, in many instances, their use is limited by poor performance under the conditions of pH and temperature required by the industry. Therefore, the search for xylanases able to function efficiently at alkaline pH and high temperature is an important objective for different processes that use lignocellulosic substrates, such as the production of paper pulp and biofuels. Results A comprehensive in silico analysis of family GH11 sequences from the CAZY database allowed their phylogenetic classification in a radial cladogram in which sequences of known or presumptive thermophilic and alkalophilic xylanases appeared in three clusters. Eight sequences from these clusters were selected for experimental analysis. The coding DNA was synthesized, cloned and the enzymes were produced in E. coli. Some of these showed high xylanolytic activity at pH values > 8.0 and temperature > 80 °C. The best enzymes corresponding to sequences from Dictyoglomus thermophilum (Xyn5) and Thermobifida fusca (Xyn8). The addition of a carbohydrate-binding module (CBM9) to Xyn5 increased 4 times its activity at 90 °C and pH > 9.0. The combination of Xyn5 and Xyn8 was proved to be efficient for the saccharification of alkali pretreated rice straw, yielding xylose and xylooligosaccharides. Conclusions This study provides a fruitful approach for the selection of enzymes with suitable properties from the information contained in extensive databases. We have characterized two xylanases able to hydrolyze xylan with high efficiency at pH > 8.0 and temperature > 80 °C.

Xylooligosaccharides (XOS) are the oligomers of β-1,4 linked xylose monomers and they have health promoting effect by modulating the beneficial microorganisms in intestine. In this study, hydrolysate obtained from hemp (Cannabis sativa) shives was investigated in terms of its in vitro toxicological impacts at cellular and genetic levels and antioxidant activity. The hydrolysate was found to contain 0.264 mg mL-1 of xylose, 0.789 mg mL-1 of xylobiose and 0.171 mg mL-1 of xylotriose in addition to hydroxymethlyfurfural (HMF) and furfural (F) at concentrations of 0.545 mg mL-1 and 0.107 mg mL-1, respectively. The cells, colon epithelial cells (CoN) and colon cancer cells (Caco-2), exposed to 5.00 mg mL-1 or lower XOS hydrolysate showed very similar growth profiles to the untreated control cells. At the genetic level, the oxidative responses of the cell types to XOS hydrolysate were different as measured by NFE2L2 (Nuclear factor, erythroid-derived 2-like 2) gene expression. Regarding antioxidant activity, the amount of XOS hydrolysate (IC50) that cleared 50 % of the 2,2-diphenyl-l-picrylhydrazyl (DPPH) in the medium was calculated as 0.12 mg mL-1. To conclude, based on in vitro studies, XOS hydrolysate obtained from lignocellulosic hemp shives emerges as an innovative, alternative and safe functional food candidate.

Xylooligosaccharides (XOS) are functional feed additives that are attracting growing commercial interest owing to their excellent ability to modulate the composition of the gut microbiota. The acid hydrolysis-based processing of xylan-containing materials has been proposed to represent a cost-effective approach to XOS preparation, with organic acids being preferable in this context. As such, in the present study, maleic acid was selected as a mild, edible organic acid for use in the hydrolysis of xylan to produce XOS. A response surface methodology (RSM) approach with a central composite design was employed to optimize maleic acid-mediated XOS production, resulting in a yield of 50.3% following a 15 min treatment with 0.08% maleic acid at 168°C. Under these conditions, the desired XOS degree of polymerization (2-3) was successfully achieved, demonstrating the viability of this using a low acid dose and a high reaction temperature to expedite the production of desired functional products. Moreover, as maleic acid is a relatively stable carboxylic acid, it has the potential to be recycled. These results suggest that dilute maleic acid-based thermal treatment of corncob-derived xylan can achieve satisfactory XOS yields, highlighting a promising and cost-effective approach to XOS production.

Background: This study investigated a novel in ovo feeding strategy to determine the prebiotic effects of xylo- and mannan- oligosaccharides (XOS and MOS) differing in the degree of polymerization. A total of 192 fertilized eggs were divided into 6 treatment groups: i) normal saline control (NSC), ii) xylotriose (XOS3), iii) xylotetraose (XOS4), iv) mannotriose (MOS3), v) mannotetraose (MOS4), and vi) no injection control (NIC), each containing 4 replicate trays with 8 eggs per replicate. On d 17 of incubation, 3 mg of oligosaccharides (except for controls) dissolved in 0.5 mL of 0.85% normal saline were injected into the amnion of Cobb 500 broilers eggs. After hatch, the chicks were raised for 28 d under standard husbandry practices and were fed a commercial broilers diet ad libitum, and samples were collected periodically. Results: The hatchability, growth performance, and relative weights of breast, drumstick, liver, and proventriculus were not different among the treatments (P > 0.05). The XOS3 injection increased the total short-chain fatty acid production at d 28 compared with both control groups (P < 0.05). The villus height to crypt depth ratio was significantly higher in the XOS4 group than both controls on the hatch day (P < 0.01) but were not different among any treatments on d 7 and 28 (P > 0.05). On the hatch day, the expression level of the CD3 gene (a T cell marker) was increased by XOS3, while the IL-10 gene (a marker of anti-inflammatory cytokine) was reduced by MOS4 (P < 0.05) compared with both controls. Compared with both controls, XOS3 exhibited a trend of reduction for IL-10 (P = 0.074). No cytokines or lymphocyte markers were affected by the treatments on d 7 (P > 0.05), except XOS4 increased IL-4 compared with NSC (P < 0.05). The broilers in the MOS4 group had higher operational taxonomic units (OTUs) and had more differentially abundant taxa, including order Lactobacillales and family Leuconostocaceae (P < 0.05) than both controls on d 28. The predictive functional profiling indicated that the linoleic acid metabolism pathway was enriched in the cecal microbiota of the XOS3 group compared with both controls (P < 0.05). Conclusion: The effects of these XOS and MOS on ileal mucosa and immunity are transient, but the effects on fermentation and cecal microbiota are prolonged, and further research is warranted to determine their use as a gut health promoter in poultry. [ABSTRACT FROM AUTHOR]

Purpose: The present study aims to recover value-added products from fresh pineapple processing wastes in an integrated biorefinery. Methods: Bromelain, a therapeutic protease, was extracted from pineapple by-products via an aqueous, low-temperature process. Bromelain-free biomass was rich in insoluble fibre and was further fractionated into hemicellulose, cellulose and lignin. Results: The highest content of active bromelain was obtained from pineapple core waste of the different varieties namely, Smooth Cayenne (~ 1.9 ± 0.05 CDU/mg), Giant Kew (1.6 ± 0.05 CDU/mg) and MD2 (1.5 ± 0.1 CDU/mg). The activity of extracted bromelain was close to commercial stem bromelain (2.2 ± 0.1 CDU/mg, % purity of 95–96%). The fractionation of fibrous residue (97.2 ± 0.5 g/100 g of dry mass) was optimised, and maximum yield of hemicellulose (97.5 ± 0.2%) was obtained with 5% (w/v) alkali at the end of 1.5 h. The hemicellulose and cellulose-rich residues were further valorised into xylooligosaccharides (26.1 ± 0.4 g/100 g of hemicellulose) and glucose (85.3 ± 1.7 g/100 g of cellulose-rich residue), respectively. From one ton of fresh pineapple processing waste, ~ 1 kg bromelain, ~ 24 kg xylooligosaccharides, ~ 88 kg glucose and ~ 68 kg residual hemicellulose could be obtained. Conclusion: The proposed biorefinery concept not only addresses the environmental issues but also creates an opportunity to generate wealth in the form of products required for food and pharmaceutical industries from processing waste. As demand for more natural products is rising and consumers choice are prompted by healthy foods, conversion of pineapple waste into above mentioned valuable products creates a niche in food and therapeutics industry. Schematic for extraction of bromelain coupled with co-production of xylooligosaccharides and glucose from pineapple waste. [ABSTRACT FROM AUTHOR]

Pre-hydrolysis-kraft of Eucalyptus globulus by autohydrolysis (batch) and with dilute acid hydrolysis (flow-through reactor) were explored in this study, to examine the recovery of xylooligosaccharides (XOs) from the pre-hydrolysis treatment. The results of this work support the potential reuse of the hydrolysate to increase the recovery yield of added value compounds. The pH of the dilute acid hydrolysis was maintained at 3.5 with acetic acid, to mimic the conditions of the batch reactor medium (autohydrolysis). An increase of XOs recovered was evident when the pre-treatment was in the flow-through reactor instead of the batch reactor. In the latter, a high concentration of furfural was recovered, showing the influence of time in XO conversion through hydrolysis. The total yield of pulp was higher in the flow-through reactor (36.4%) in comparison with the batch system (34.5%) after kraft pulping, which was expected, given the increasing time that the hydrolysate was present in the reactor; however, the difference was small and could have been the result of precipitated compounds in the latter, so this needs further analysis. [ABSTRACT FROM AUTHOR]

The hemicellulose content present in corn cobs can help in producing a high amount of xylooligosaccharides (XOS) in an eco-friendly manner. In this work, the XOS was produced from alkali pre-treated corn-cobs having a true yield of 38 ± 1.4% via enzymatic hydrolysis with the help of xylanase from T. lanuginosus VAPS-24. The production process was optimized to achieve a high concentration of XOS using innovative multi-objective optimization through machine learning modeling and finding out the most suitable parameters where xylobiose production is higher than xylose. The Multi-objective connected neural networks (MOCNN) model with tangent sigmoid activation function yielded a correlation coefficient of 96.51%; there were six optimal sets where xylobiose concentration was higher than xylose. The best-optimized conditions yielded 3.03 mg/ml of xylobiose and 1.31 mg/ml of xylose. Therefore, this novel approach of machine learning can target the increasing demand for xylooligosaccharides in the growing industrial market of prebiotics. [ABSTRACT FROM AUTHOR]

Objective: To develop an endo-β-1,4-xylanase with high specificity for production of prebiotic xylooligosaccharides that optimally works at moderate temperature desirable to reduce the energy cost in the production process. Results: The xylB gene, encoding for a glycosyl hydrolase family 11 xylanase from a thermoresistant fungus, Aspergillus niger BCC14405 was expressed in a methylotrophic yeast P. pastoris KM71 in a secreted form. The recombinant XylB showed a high specific activity of 3852 and 169 U mg−1 protein on beechwood xylan and arabinoxylan, respectively with no detectable side activities against different forms of cellulose (Avicel Ò PH101 microcrystalline cellulose, phosphoric acid swollen cellulose and carboxymethylcellulose). The enzyme worked optimally at 45 °C, pH 6.0. It showed a specific cleavage pattern by releasing xylobiose (X2) as the major product from xylooligosaccharides (X3 to X6) substrates. The highest XOS yield of 708 mg g−1 substrate comprising X2, X3 and X6 was obtained from beechwood xylan hydrolysis. Conclusion: The enzyme is potent for XOS production and for saccharification of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of the high level of xylooligosaccharides (XOS) on growth performance, antioxidant capability, immune function, and fecal microbiota in weaning piglets. The results showed that 28 d body weight exhibited linear and quadratic increases (P < 0.05) with increasing dietary XOS level, as well as average daily feed intake (ADFI) on d 15–28, average daily gain (ADG) on d 15–28 and 1–28. There was a linear decrease (P < 0.05) between XOS levels and feed conversion rate (FCR) on d 1–14 and 1–28. Additionally, glutathione peroxidase (GSH-Px) showed a linear increase (P < 0.05), while the malondialdehyde (MDA) level decreased linearly and quadratically (P < 0.05) with the increasing dietary level of XOS. Moreover, the XOS treatments markedly increased the levels of immunoglobulin A (Ig A) (linear, P < 0.05; quadratic, P < 0.05), IgM (quadratic, P < 0.05), IgG (linear, P < 0.05), and anti-inflammatory cytokine interleukin-10 (IL-10) (quadratic, P < 0.05) in serum, while the IL-1β (linear, P < 0.05; quadratic, P < 0.05) and IL-6 (linear, P < 0.05) decreased with increasing level of XOS. Microbiota analysis showed that dietary supplementation with 1.5% XOS decreased (P < 0.05) the α-diversity and enriched (P < 0.05) beneficial bacteria including Lactobacillus, Bifidobacterium, and Fusicatenibacter at the genus level, compared with the control group. Importantly, linearly increasing responses (P < 0.05) to fecal acetate, propionate, butyrate, and total short-chain fatty acids (SCFAs) were observed with increasing level of XOS. Spearman correlation analyses found that Lactobacillus abundance was positively correlated with ADG, acetate, propionate, and IgA (P < 0.05), but negatively correlated with IL-1β (P < 0.05). Bifidobacterium abundance was positively related with ADFI, total SCFAs, IgG, and IL-10 (P < 0.05), as well as g_Fusicatenibacter abundance with ADFI, total SCFAs, and IL-10. However, Bifidobacterium and Fusicatenibacter abundances were negatively associated with MDA levels (P < 0.05). In summary, dietary supplementation with XOS can improve the growth performance in weaning piglets by increasing antioxidant capability, enhancing immune function, and promoting beneficial bacteria counts.

A significant part of fruit production is wasted annually, a material of high value without use, causing environmental and social damage. These residues from agro-industrial processes, or those that can no longer be used in the market, can be recycled and generate value-added products by pretreatments/hydrolysis. One of the important pretreatments is acid hydrolysis, which can produce xylooligosaccharides (XOS) from biomass, a product of great commercial value in the food and pharmaceutical markets, mainly due to its prebiotic potential. Bananas, oranges, and guava generate a large volume of waste and represent much of Brazil’s fruit production. The dilute acid hydrolysis resulted in XOS production of 37.69% for banana peel, 59.60% for guava bagasse, 28.70% for orange bagasse, and 49.64% for restaurant residue. XOS were quantified by a liquid chromatograph system with a Bio-Rad Aminex HPX-87C column. The results show that, for this type of material and hydrolysis, the ideal conditions to produce XOS are high temperature, low time, and high acid concentration for banana peel residue (160 °C, 15 min, and 3% H2SO4), low temperature, low time, and high acid concentration for guava bagasse (100 °C,15 min and 3% H2SO4), high temperature and acid concentration with low time for orange bagasse (160 °C,15 min and 3% H2SO4) and high temperature and time and high acid concentration for restaurant waste (160 °C, 55 min and 3% H2SO4). This study identified acid hydrolysis conditions that maximized XOS production with a low amount of xylose production using agro-industrial and food residues, also showing the high potential of the chosen residues through the high yields of XOS production.

A new biphasic organic solvent, phenoxyethanol-maleic acid, was carried out to pretreat and fractionate vinegar residue into glucan, xylan and lignin under mild conditions. Additional effects of key factors, temperature and phenoxyethanol concentration, on vinegar residue, were evaluated. Under the biphasic system (0.5% maleic acid, 60% phenoxyethanol), 140 °C cooking vinegar residue for 1 h, 80.91% of cellulose retention in solid residue, 75.44% of hemicellulose removal and 69.28% of lignin removal were obtained. Optimal identified conditions resulted in maximum XOS of 47.3%. Then, the solid residue was enzymatically digested with a glucose yield of 82.67% at 72 h with the addition of 2.5 g/L bovine serum albumin. Finally, the residue was characterized by SEM, FTIR, XRD and BET analysis. This work demonstrated the phenoxyethanol-maleic acid pretreatment yielded XOS, fermentable sugar, and lignin with high processibility.

Barley straw was subjected to hydrothermal pretreatment (steam explosion) processing to evaluate its potential as a raw material to produce xylooligosaccharides (XOS) suitable for use as a prebiotic. The steam explosion pretreatment generated a liquid fraction containing solubilised hemicellulose. This fraction was purified using gel permeation chromatography to obtain a fraction rich in XOS DP2-DP6. The sample was characterised through analytical techniques such as HPAEC-PAD, FTIR and MALDI-TOF-MS. The prebiotic activity was evaluated using in vitro fermentation in human faecal cultures through the quantification of short-chain fatty acid (SCFA) and lactate production, the evolution of the pH and the consumption of carbon sources. The total SCFA production at the end of fermentation (30 h) was 90.1 mM. Positive significant differences between the amount of XOS from barley straw and fructooligosaccharides after incubation were observed.

Xylooligosaccharide (XOS) is a source of prebiotics with multiple biological activities. The present study aimed to investigate the effects of XOS on mice fed a high-fat diet. Mice were fed either a normal diet or a high-fat diet supplemented without or with XOS (250 and 500 mg/kg), respectively, for 12 weeks. The results showed that the XOS inhibited mouse weight gain, decreased the epididymal adipose index, and improved the blood lipid levels, including triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels. Moreover, XOS reduced the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and alleviated the damage to the liver caused by the high-fat diet. XOS also reduced hyperlipidemia-associated inflammatory responses. Additionally, quantitative real-time polymerase chain reaction results showed that XOS intervention activated the AMP-activated protein kinase (AMPK) pathway to regulate the fat synthesis, decomposition, and β oxidation; upregulated the mRNA expression levels of carnitine palmitoyl transferase 1 (CPT-1), peroxisome proliferator–activated receptors α (PPAR-α), and cholesterol 7-alpha hydroxylase (CYP7A1); and downregulated the mRNA expression levels of acetyl-CoA carboxylase (ACC), CCAAT/enhancer-binding protein alpha (C/EBPα), and lipoprotein lipase (LPL). On the other hand, XOS enhanced the mRNA expression levels of zonula occludens-1 (ZO-1), occludin, and claudin-1 in the small intestine; increased the strength of the intestinal barrier; and optimized the composition of the intestinal microbiota. Therefore, it was concluded that XOS regulated the intestinal barrier, changed the intestinal microecology, and played an important role in preventing hyperlipidemia through the unique anatomical advantages of the gut–liver axis.

Xylooligosaccharide (XOS) is a source of prebiotics with multiple biological activities. The present study aimed to investigate the effects of XOS on mice fed a high-fat diet. Mice were fed either a normal diet or a high-fat diet supplemented without or with XOS (250 and 500 mg/kg), respectively, for 12 weeks. The results showed that the XOS inhibited mouse weight gain, decreased the epididymal adipose index, and improved the blood lipid levels, including triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels. Moreover, XOS reduced the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and alleviated the damage to the liver caused by the high-fat diet. XOS also reduced hyperlipidemia-associated inflammatory responses. Additionally, quantitative real-time polymerase chain reaction results showed that XOS intervention activated the AMP-activated protein kinase (AMPK) pathway to regulate the fat synthesis, decomposition, and β oxidation; upregulated the mRNA expression levels of carnitine palmitoyl transferase 1 (CPT-1), peroxisome proliferator–activated receptors α (PPAR-α), and cholesterol 7-alpha hydroxylase (CYP7A1); and downregulated the mRNA expression levels of acetyl-CoA carboxylase (ACC), CCAAT/enhancer-binding protein alpha (C/EBPα), and lipoprotein lipase (LPL). On the other hand, XOS enhanced the mRNA expression levels of zonula occludens-1 (ZO-1), occludin, and claudin-1 in the small intestine; increased the strength of the intestinal barrier; and optimized the composition of the intestinal microbiota. Therefore, it was concluded that XOS regulated the intestinal barrier, changed the intestinal microecology, and played an important role in preventing hyperlipidemia through the unique anatomical advantages of the gut–liver axis. [ABSTRACT FROM AUTHOR]

This study focused on the applying endo-xylanases to reduce the use of bleaching agent, coupled with the production of xylooligosaccharides (XOs), in mulberry paper making. Paper mulberry pulp (PMP) was consecutively prepared from paper mulberry bark by traditional NaOH-treatment, and two types of thermostable endo-xylanase from Streptomyces thermovulgaris TISTR1948 (wild-type and recombinant endo-xylanases) were employed in the biobleaching of PMP. This process was optimized to achieve maximum XOs yields and the highest PMP quality. The optimal condition was an enzyme dosage of 125 U/g PMP at 12 h of reaction time, both in a 500 mL laboratory bottle and a 150 L reactor. The mixture obtained from the reactor was separated as liquid of XOs derived from PMP (PMP-XOs) and solid biobleached PMP. The PMP-XOs from wild-type endo-xylanase were composed of 31.6% xylopentaose (X5), 30.9% xylohexaose and higher-degree XOs (X ≥ 6), and 11.7% xylobiose (X2), whereas 76.6% of X5 and 8.6% of X2 were the main products from recombinant endo-xylanase. The PMP-XOs derived from both endo-xylanase types exhibited high antioxidant activities, reducing power, phenolic contents, and prebiotic efficacy. In addition, the application of both endo-xylanases enhanced the brightness of PMP by 5.1% and 3.5%, and reduced the kappa number by 9.1% and 3.6%, respectively. Biobleached PMP was subsequently subjected to the NaOCl bleaching step to produce the mulberry paper. This approach could reduce NaOCl consumption by 20–25%, making it an environmentally friendly alternative. The production of valuable prebiotics, such as PMP-XOs, further enhances the economic viability of this approach. [ABSTRACT FROM AUTHOR]

Bacillus sp. AR03 have been described as an important producer of carbohydrate-active enzymes (CAZymes) when growing in a peptone-based medium supplemented with simple sugars and/or carboxymethyl cellulose (CMC) as carbon sources. This work aimed to identify the extracellular enzymatic cocktails through shotgun proteomics. The proteomic analysis showed that enzymes involved in cellulose and xylan degradation were among the most abundant proteins. These enzymes included an endo-glucanase GH5_2 and a glucuronoxylanase GH30_8, which were found in all conditions. In addition, several proteins were differentially expressed in the three evaluated culture media, indicating microbial metabolic changes due to the different supplied carbon sources, particularly, in the presence of CMC. Finally, the capability of the crude enzymatic cocktails from culture media to degrade birchwood xylan was assessed, which produced mostly xylooligosaccharides containing among 3–5 xylose units. Consequently, this work shows the potential of the extracellular enzymes from Bacillus sp. AR03 for producing emergent prebiotics. [ABSTRACT FROM AUTHOR]

The genus Cohnella belongs to a group of Gram-positive endospore-forming bacteria within the Paenibacillaceae family. Although most species were described as xylanolytic bacteria, the literature still lacks some key information regarding their repertoire of xylan-degrading enzymes. The whole genome sequence of an isolated xylan-degrading bacterium Cohnella sp. strain AR92 was found to contain five genes encoding putative endo-1,4-β-xylanases, of which four were cloned, expressed, and characterized to better understand the contribution of the individual endo-xylanases to the overall xylanolytic properties of strain AR92. Three of the enzymes, CoXyn10A, CoXyn10C, and CoXyn11A, were shown to be effective at hydrolyzing xylans-derived from agro-industrial, producing oligosaccharides with substrate conversion values of 32.5%, 24.7%, and 10.6%, respectively, using sugarcane bagasse glucuronoarabinoxylan and of 29.9%, 19.1%, and 8.0%, respectively, using wheat bran-derived arabinoxylan. The main reaction products from GH10 enzymes were xylobiose and xylotriose, whereas CoXyn11A produced mostly xylooligosaccharides (XOS) with 2 to 5 units of xylose, often substituted, resulting in potentially prebiotic arabinoxylooligosaccharides (AXOS). The endo-xylanases assay displayed operational features (temperature optima from 49.9 to 50.4 °C and pH optima from 6.01 to 6.31) fitting simultaneous xylan utilization. Homology modeling confirmed the typical folds of the GH10 and GH11 enzymes, substrate docking studies allowed the prediction of subsites (− 2 to + 1 in GH10 and − 3 to + 1 in GH11) and identification of residues involved in ligand interactions, supporting the experimental data. Overall, the Cohnella sp. AR92 endo-xylanases presented significant potential for enzymatic conversion of agro-industrial by-products into high-value products. Key points • Cohnella sp. AR92 genome encoded five potential endo-xylanases. • Cohnella sp. AR92 enzymes produced xylooligosaccharides from xylan, with high yields. • GH10 enzymes from Cohnella sp. AR92 are responsible for the production of X2 and X3 oligosaccharides. • GH11 from Cohnella sp. AR92 contributes to the overall xylan degradation by producing substituted oligosaccharides. [ABSTRACT FROM AUTHOR]

In order to improve the daily intake of prebiotic fiber in the staple foods of the Mediterranean diet, the potential of including prebiotic xylooligosaccharides (XOS) in spreadable goat cheese was investigated. Preliminarily, this study aimed to obtain XOS extract from vine shoots by steam explosion. Thus, xylooligosaccharide extract (XE), also used as purified extract (XEP) were added in the goat cheese. The application of XE and XEP in the cheese, significantly changed the proximal composition, providing more than 3 g of fiber per 100 g allowing the claim "source of fiber" according with the EU Regulation 1924/2006, reducing further the predicted glycemic index. The purification treatment of the extract highlighted the potential of XEP in promoting a healthier gut microbiota by stimulating the growth of Bifidobacterium and lactic acid bacteria. Structure analysis and volatile profile showed a great similarity between the samples added with XEP and the control cheese. [Display omitted] • Xylooligosaccharides (XOS) were obtained from vine shoots with steam explosion technology. • The purification of XOS extract eliminates compounds that inhibit microbial growth. • Purified XOS in spreadable goat cheese showed a presence of fiber with prebiotic action. • Spreadable goat cheese with XOS promotes the growth of a good gut microbiota. [ABSTRACT FROM AUTHOR]

Production of value-added compounds and sustainable materials from agro-industrial residues is essential for better waste management and building of circular economy. This includes valorization of hemicellulosic fraction of plant biomass, the second most abundant biopolymer from plant cell walls, aiming to produce prebiotic oligosaccharides, widely explored in food and feed industries. In this work, we conducted biochemical and biophysical characterization of a prokaryotic two-domain R. champanellensis xylanase from glycoside hydrolase (GH) family 30 (Rc Xyn30A), and evaluated its applicability for XOS production from glucuronoxylan in combination with two endo -xylanases from GH10 and GH11 families and a GH11 xylobiohydrolase. Rc Xyn30A liberates mainly long monoglucuronylated xylooligosaccharides and is inefficient in cleaving unbranched oligosaccharides. Crystallographic structure of Rc Xyn30A catalytic domain was solved and refined to 1.37 Å resolution. Structural analysis of the catalytic domain releveled that its high affinity for glucuronic acid substituted xylan is due to the coordination of the substrate decoration by several hydrogen bonds and ionic interactions in the subsite −2. Furthermore, the protein has a larger β5-α5 loop as compared to other GH30 xylanases, which might be crucial for creating an additional aglycone subsite (+3) of the catalytic site. Finally, Rc Xyn30A activity is synergic to that of GH11 xylobiohydrolase. [Display omitted] [ABSTRACT FROM AUTHOR]