Sugar Oligomers Research Articles

Catalyst-recirculating system in steam explosion pretreatment for producing high-yield of xylooligosaccharides from oat husk

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.

Xylooligosaccharides from lignocellulosic biomass and their applications as nutraceuticals: a review on their production, purification, and characterization.

Xylooligosaccharides (XOS) are considered a potent source of prebiotics for humans. The global prebiotic market is expanding in size, was valued at USD 6.05 billion in 2021, and is expected to grow at a 14.9% compound annual growth rate between 2022 and 2030, indicating a huge demand. These XOS are non-digestible pentose sugar oligomers comprising mainly xylose. Xylose is naturally present in the lignocellulosic biomass (LCB), fruits and vegetables. Apart from the prebiotic effect, these XOS have been reported to reduce blood cholesterol, possess antioxidant effects, increase calcium absorption, reduce colon cancer risk, and benefit diabetic patients. The primary use of XOS is reported in the feed industry followed by health, medical use, food and drinks. LCB mainly contains glucan, xylan and lignin. After glucan, xylan is the second-highest available sugar on the globe composed of xylose. Therefore, the xylan fraction of LCB has great significance in producing food, feed and energy. Glucan has been exploited for the commercial production of ethanol, xylitol, furfural, hydroxymethyl furfural and glucose. As of now, xylan has limited applications. Therefore, xylan can be exploited to convert to XOS. The production of XOS from LCB fraction not only helps to produce these at a very low price, but also helps in the reduction of greenhouse gases. Its use in food and drinks is increasing as it can be derived from the abundantly and cheaply available LCB. The article provides a review on the production, purification and characterization of XOS in view of their use as nutraceuticals. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A GH81-type β-glucan-binding protein enhances colonization by mutualistic fungi in barley

Cell walls are important interfaces of plant-fungal interactions, acting as robust physical and chemical barriers against invaders. Upon fungal colonization, plants deposit phenolics and callose at the sites of fungal penetration to prevent further fungal progression. Alterations in the composition of plant cell walls significantly impact host susceptibility. Furthermore, plants and fungi secrete glycan hydrolases acting on each other's cell walls. These enzymes release various sugar oligomers into the apoplast, some of which activate host immunity via surface receptors. Recent characterization of cell walls from plant-colonizing fungi has emphasized the abundance of β-glucans in different cell wall layers, which makes them suitable targets for recognition. To characterize host components involved in immunity against fungi, we performed a protein pull-down with the biotinylated β-glucan laminarin. Thereby, we identified a plant glycoside hydrolase family 81-type glucan-binding protein (GBP) as a β-glucan interactor. Mutation of GBP1 and its only paralog, GBP2, in barley led to decreased colonization by the beneficial root endophytes Serendipita indica and S.vermifera, as well as the arbuscular mycorrhizal fungus Rhizophagus irregularis. The reduction of colonization was accompanied by enhanced responses at the host cell wall, including an extension of callose-containing cell wall appositions. Moreover, GBP mutation in barley also reduced fungal biomass in roots by the hemibiotrophic pathogen Bipolaris sorokiniana and inhibited the penetration success of the obligate biotrophic leaf pathogen Blumeria hordei. These results indicate that GBP1 is involved in the establishment of symbiotic associations with beneficial fungi-a role that has potentially been appropriated by barley-adapted pathogens.

Elucidation of Structure and Physical Properties of Pyrolytic Sugar Oligomers Derived from Cellulose Depolymerization/Dehydration Reactions: A Density Functional Theory Study

Fast pyrolysis of lignocellulosic materials is a promising research area to produce renewable fuels and chemicals. Dehydration is known to be among the most important reaction families during cellulose pyrolysis; water is the most important product. Together with water, dehydration reactions also form a range of poorly known oligomer species of varying molecular sizes, often collected as part of the bio-oil water-soluble (WS) fraction. In this work, we used electronic structure calculations to evaluate the relative thermodynamic stabilities of several oligomer species from cellulose depolymerization intermediates undergoing three consecutive dehydration events. A library of the thermodynamically favored candidate molecular structures was compiled. Results revealed that most of the water molecules are eliminated from the non-reducing end, forming thermodynamically more stable conjugated compounds. This is consistent with results reported in literature where dehydration reactions occur preferably at the non-reducing ends of oligomers. The theoretical Fourier-Transform Infrared Spectroscopy and NMR spectra of these proposed sugar oligomers conform qualitatively to the experimental result of pyrolytic sugars. Understanding their chemical structure could help to develop rational strategies to mitigate coke formation as sugars are often blamed to cause coke formation during bio-oil refining. The estimated physical–chemical properties (boiling point, melting point, Gibbs free energy of formation, enthalpy of formation, and solubility parameters among others) are also fundamental to conducting first-principles engineering calculations to design and analyze new pyrolysis reactors and bio-oil up-grading units.

Valorization of Cereal Byproducts with Supercritical Technology: The Case of Corn

Ethanol and starch are the main products generated after the processing of corn via dry grinding and wet milling, respectively. Milling generates byproducts including stover, condensed distillers’ solubles, gluten meal, and the dried distillers’ grains with solubles (DDGS), which are sources of valuable compounds for industry including lignin, oil, protein, carotenoids, and phenolic compounds. This manuscript reviews the current research scenario on the valorization of corn milling byproducts with supercritical technology, as well as the processing strategies and the challenges of reaching economic feasibility. The main products recently studied were biodiesel, biogas, microcapsules, and extracts of enriched nutrients. The pretreatment of solid byproducts for further hydrolysis to produce sugar oligomers and bioactive peptides is another recent strategy offered by supercritical technology to process corn milling byproducts. The patents invented to transform corn milling byproducts include oil fractionation, extraction of undesirable flavors, and synthesis of structured lipids and fermentable sugars. Process intensification via the integration of milling with equipment that operates with supercritical fluids was suggested to reduce processing costs and to generate novel products.

Tracking swelling of lignocellulosic biomass during acid hydrolysis by using size-exclusion chromatography to evaluate molecular size

The two-step concentrated acid hydrolysis process is very efficient in producing fermentable sugars from lignocellulosic biomass, but acid recovery is important for the economic viability of the process. During membrane or precipitation-based separation of the acid catalyst from sugar oligomers and monomers, the molecular sizes of the sugar molecules will influence sugar entrainment with the acid. This study applied size-exclusion chromatography to determine the molecular size distribution of the water-soluble sugar molecules generated during the concentrated acid swelling of lignocellulosic biomass. Two indicators were calculated from the chromatograms to describe the distribution: the relative area of the chromatogram and the ratio of small molecules versus large molecules. Measurable changes in these indicators could be related to changes in the operating conditions of the swelling step, and to downstream hydrolysis performance. This approach provided important information about the swelling progression that will be useful for optimizing the hydrolysis process, and especially when implementing an acid recovery step.

Glycoprofiling of Oligosaccharides of Regular and Lactose-Free Milk by Mass Spectrometry

Oligosaccharides from regular milk and lactose-free milk were analyzed by Electrospray Ionization interface coupled with Ion Trap Mass Spectrometry (IT-MS). The negative mode mass spectrometry of sugar compositions was obtained either by direct infusion and mass spectrometry with Liquid Chromatography (LC). Hexose (Hex) and the other oligomeric sugar components were observed in both regular and lactose-free milk. While lactose derivatives (deprotonated lactose dimer, chloride adducts, chloride dimer) in regular milk have seen to be dominated, monosaccharide derivatives (Hex-H2O, Hex, Hex-Cl) in the lactose-free milk were observed as abundant which was lytic product of lactose. Phosphate/sulfate ester substitution on lactose and sialyllactose in both regular and lactose-free milk samples were observed with similar intensity thus it has been understood that these important milk components are not digested during lactose removing process.

Lectins from plants and algae act as anti-viral against HIV, influenza and coronaviruses.

BackgroundCarbohydrate–lectin interactions are extremely specific as the lectin is capable of recognising monomeric and oligomeric sugars in a reversible manner. It has been known for a long time that lectins have antibacterial, antifungal, and insecticidal activities. Recently, it has been reported that many lectins can prevent the virus growth by interacting with the viral envelop surface glycoprotein. Spike protein, which is found on the surface of some enveloped viruses, is heavily mannosylated and will have strong affinity for mannose specific lectins. According to the findings, lectins have a high binding affinity for the glycans of the SARS-CoV-2 spike glycoprotein, which contains N-glycosylation sites. As a result, various lectins are being researched and developed as anti-viral agents.ResultsAccording to our in silico studies, the amino acid residues Asn487, Tyr489, Gln493, Lys417, and Tyr505 of the receptor binding domain (RBD) of SARS-CoV-2 formed an interaction with the model lectin Lablab purpureus lectin. Similar interaction for SARS-CoV-2 spike protein was observed with Griffithsin lectin (algal source) as well. These observations demonstrate that lectins could be one of the potential molecules for neutralising coronavirus infection.ConclusionThis review focuses on anti-viral lectins isolated and characterized from plants and algae (last 5 years) and showed anti-viral properties against HIV, Influenza, and coronaviruses.

Enzyme inhibitory activity of Dioscorea nipponica Makito hydroethanolic extracts of leaves and tubers in relation to their major secondary metabolites

Different anatomical parts of Dioscorea nipponica Makito have been used in foods and folk medicines for their nutritional and pharmacological properties; however, the scientific data on enzyme inhibitory activities and phytochemicals in plant extracts remain rather scarce. Such information is important for expanding possible uses of plant origin preparations in nutrition. This study, using commonly applied assays, evaluated inhibitory activity of 70% ethanol extract of D. nipponica leaves and tubers against such physiologically important enzymes as α-amylase, α-glucosidase, acethylcholinesterase, and angiotensin-converting enzyme (ACE). Inhibition of α-glucosidase and acethylcholinesterase required lower leaf extract concentrations as compared with other two enzymes. The IC50 values of α-glucosidase and α-amylase inhibition were 66.08 and 438 μg/mL, respectively, while the inhibition of ACE at 250–1250 μg/mL was from 28.02 ± 1.17% to 77.13 ± 0.78%. The mode of inhibition of α-glucosidase and acethylcholinesterase was evaluated by the kinetic studies. Leaf and tuber extracts displayed a mixed-type non-competitive mode of α-glucosidase inhibition. Phytochemical composition of extracts was determined by UPLC-QTOF/MS and HPLC-UV methods. Leaf extract was remarkably stronger enzyme inhibitor than tuber extract and it may be explained by the differences in the secondary metabolite composition. Quinic, chlorogenic acids and quercetin glycosides, which are well-known enzyme inhibitors, were the main phytochemicals in the leaf extract, while steroidal glycosides, peptides and oligomeric sugars were the major constituents in the tuber extract. It is expected that new knowledge on D. nipponica will serve for its valorisation in developing new health beneficial ingredients for functional foods and nutraceuticals.

Utilization of lignocellulosic biofuel conversion residue by diverse microorganisms

BackgroundLignocellulosic conversion residue (LCR) is the material remaining after deconstructed lignocellulosic biomass is subjected to microbial fermentation and treated to remove the biofuel. Technoeconomic analyses of biofuel refineries have shown that further microbial processing of this LCR into other bioproducts may help offset the costs of biofuel generation. Identifying organisms able to metabolize LCR is an important first step for harnessing the full chemical and economic potential of this material. In this study, we investigated the aerobic LCR utilization capabilities of 71 Streptomyces and 163 yeast species that could be engineered to produce valuable bioproducts. The LCR utilization by these individual microbes was compared to that of an aerobic mixed microbial consortium derived from a wastewater treatment plant as representative of a consortium with the highest potential for degrading the LCR components and a source of genetic material for future engineering efforts.ResultsWe analyzed several batches of a model LCR by chemical oxygen demand (COD) and chromatography-based assays and determined that the major components of LCR were oligomeric and monomeric sugars and other organic compounds. Many of the Streptomyces and yeast species tested were able to grow in LCR, with some individual microbes capable of utilizing over 40% of the soluble COD. For comparison, the maximum total soluble COD utilized by the mixed microbial consortium was about 70%. This represents an upper limit on how much of the LCR could be valorized by engineered Streptomyces or yeasts into bioproducts. To investigate the utilization of specific components in LCR and have a defined media for future experiments, we developed a synthetic conversion residue (SynCR) to mimic our model LCR and used it to show lignocellulose-derived inhibitors (LDIs) had little effect on the ability of the Streptomyces species to metabolize SynCR.ConclusionsWe found that LCR is rich in carbon sources for microbial utilization and has vitamins, minerals, amino acids and other trace metabolites necessary to support growth. Testing diverse collections of Streptomyces and yeast species confirmed that these microorganisms were capable of growth on LCR and revealed a phylogenetic correlation between those able to best utilize LCR. Identification and quantification of the components of LCR enabled us to develop a synthetic LCR (SynCR) that will be a useful tool for examining how individual components of LCR contribute to microbial growth and as a substrate for future engineering efforts to use these microorganisms to generate valuable bioproducts.

Chemical and Enzymatic Synthesis of Biobased Xylo-Oligosaccharides and Fermentable Sugars from Wheat Straw for Food Applications.

Xylo-oligosaccharides are sugar oligomers with 2~7 xylose units considered non-digestible fibers that can be produced from biodegradable and low-cost biomass like wheat straw. An integrated approach consisting of hydrothermal pretreatment, alkaline treatment, enzymatic treatment and the combinations thereof was applied to overcome the recalcitrance structure of the wheat straw and allow selective fractioning into fermentable sugars and xylo-oligosaccharides. The hydrolysates and processed solids were chemically characterized by High-performance liquid chromatography and Ion chromatography, and the results were expressed as function of the severity factor and statistically interpreted. The concentration of fermentable sugars (glucose, xylose, arabinose) was the highest after the combination of alkaline and enzymatic treatment with xylanase (18 g/L sugars), while xylo-oligosaccharides (xylotriose and xylotetraose) were released in lower amounts (1.33 g/L) after the same treatment. Refining experiments were carried out to obtain a purified fraction by using anion and cation exchange chromatography. The polymer adsorber resin MN-502 showed efficient removal of salts, phenols and furan derivatives. However, the xylo-oligosaccharides yields were also slightly reduced. Although still requiring further optimization of the treatments to obtain higher purified oligomer yields, the results provide information on the production of xylo-oligosaccharides and fermentable sugars from wheat straw for potential use in food applications.

Hydrothermal treatment of furfural and sugar monomers and oligomers: a model-compound approach to probe the cross-polymerization reactions in heating bio-oil

Hydrothermal treatment of furfural and sugar monomers and oligomers: a model-compound approach to probe the cross-polymerization reactions in heating bio-oil

Применение сульфитных щелоков в качестве питательной среды для культивирования продуцента молочной кислоты Rhizopus oryzae F-1030

The filamentous fungi Rhizopus oryzae are well known for their ability to hydrolyze plant polysaccharides. Representatives of this species are widely used for the production of various products, such as organic acids (lactic acid, fumaric acid), ethanol, and hydrolytic enzymes (glucoamylases, polygalacturonases). Various carbon sources such as pentose and hexose sugars are used for the synthesis of R. oryzae exoproducts. Expensive plant sugarcontaining raw materials are used in the lactic acid production by the microbiological method, which significantly increases the final cost of the product. The article demonstrates the possibility of using cheaper by-products of pulp and paper production such as sulphite liquors as an alternative source of carbon for microbiological synthesis of lactic acid. Sulphite liquors contain a large amount of carbohydrates – products of incomplete hydrolysis of cellulose such as hemicelluloses, mono- and oligomeric sugars. The composition of sulfite liquors allows us to consider them as a potential substrate for the synthesis of lactic acid by using different microorganisms. The paper considers the dependence of the lactic acid yield on the composition of the nutrient medium based on sulfite liquor and the cultivation method of the fungus R. oryzae F-1030. As additional sources of nitrogen and phosphorus, (NH4)2SO4 and KH2PO4 were introduced to the nutrient medium. The fungus R. oryzae F-1030 was cultivated by two methods: the semicontinuous culture method, when the nutrient medium was completely replaced after depletion of the reducing sugars in it; the batch culture method, when the lack of reducing sugars in the medium was compensated by the addition of concentrated sulfite liquor. Since the nutrient medium based on sulfite liquor contains the products of incomplete cellulose hydrolysis and xylans, the xylanase and cellulase activities of the fungus R. oryzae F-1030 were measured in order to determine its absorption degree of carbohydrates, contained in the nutrient medium. It was found that it is more expedient to use the semicontinuous method for the fungus R. oryzae F-1030 cultivation on a nutrient medium based on sulfite liquor in order to obtain more synthesized lactic acid. The addition of mineral sources of nitrogen and phosphorus has practically no effect on the final yield of lactic acid. For citation: Mingazova L.A., Kryakunova E.V., Kanarskaya Z.A., Kanarsky A.V. Applying Sulfite Liquors as a Nutrient Medium for Cultivation of Lactic Acid Producer Rhizopus oryzae F-1030. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 163–173. DOI: 10.37482/0536-1036-2021-5-163-173

Separation and characterization of lignin and sugars in the hydrolysate of hot water extraction of poplar wood by membrane filtration and activated carbon adsorption

Hot water extraction of poplar wood was conducted at temperatures from 190 to 200 °C for 5 to 8 min. A hemicellulose yield of 81% and a lignin yield of 38% were obtained at 200 °C for 8 min. A combined process of microfiltration, ultrafiltration, and activated carbon adsorption was developed to separate lignin and sugars in the hydrolysate of hot water extraction. Lignin recovery efficiencies of 56.7%, 26.0%, and 13.2% were attained for microfiltration, ultrafiltration, and activated carbon adsorption, respectively. The characterization of lignin revealed diversity in molecular weight and functional groups, which is beneficial for high-value valorization. The obtained hemicellulose sugars from the combined process showed a good recovery rate of 43.8% and remarkable purity of 97.5%. The purified sugars were a mixture of monomers and oligomers that consisted of arabinose, galactose, xylose, glucose, and mannose. Sugar oligomers with degrees of polymerization from 2 to 6 accounted for 21.6% of all sugars.

Selective 13 C-Labels on Repeating Glycan Oligomers to Reveal Protein Binding Epitopes through NMR: Polylactosamine Binding to Galectins.

A combined chemo‐enzymatic synthesis/NMR‐based methodology is presented to identify, in unambiguous manner, the distinctive binding epitope within repeating sugar oligomers when binding to protein receptors. The concept is based on the incorporation of 13C‐labels at specific monosaccharide units, selected within a repeating glycan oligomeric structure. No new chemical tags are added, and thus the chemical entity remains the same, while the presence of the 13C‐labeled monosaccharide breaks the NMR chemical shift degeneracy that occurs in the non‐labeled compound and allows the unique identification of the different components of the oligomer. The approach is demonstrated by a proof‐of‐concept study dealing with the interaction of a polylactosamine hexasaccharide with five different galectins that display distinct preferences for these entities.

Selective 13C‐Labels on Repeating Glycan Oligomers to Reveal Protein Binding Epitopes through NMR: Polylactosamine Binding to Galectins

AbstractA combined chemo‐enzymatic synthesis/NMR‐based methodology is presented to identify, in unambiguous manner, the distinctive binding epitope within repeating sugar oligomers when binding to protein receptors. The concept is based on the incorporation of 13C‐labels at specific monosaccharide units, selected within a repeating glycan oligomeric structure. No new chemical tags are added, and thus the chemical entity remains the same, while the presence of the 13C‐labeled monosaccharide breaks the NMR chemical shift degeneracy that occurs in the non‐labeled compound and allows the unique identification of the different components of the oligomer. The approach is demonstrated by a proof‐of‐concept study dealing with the interaction of a polylactosamine hexasaccharide with five different galectins that display distinct preferences for these entities.

Produksi dan Pemurnian Xilooligosakarida dari Xilan Tongkol Jagung menggunakan Xilanase Streptomyces P26B4 dan Khamir IP4

Xylooligosaccharides (XOS) are sugar oligomers from xylan that can be used as prebiotics to improve digestive tract health. Xylan can be extracted from corncobs which are a by-product of agriculture. The purpose of this study was to produce XOS through hydrolysis of corn cobs xylan using Streptomyces P26B4 xylanase. The products of hydrolysis also consisted of monomer xylose; for that xilooligosaccharides were purified using yeast IP4. The xylan hydrolysis products are quantitatively analyzed based on the value of reducing sugars and degree of polymerization (DP), strengthened qualitatively with TLC. Sugar component was analyzed after the addition of yeast by HPLC. P26B4 xylanase isolates had the highest activity on the 7th day incubation, pH 5,5 buffer citrate and temperature of 50°C. The lowest DP value of xylan hydrolysis was 2.49 at a concentration of 6%, and the 24th hour of incubation. TLC chromatograms showed that xylose and XOS products were produced. Purification of XOS at 6%, showed a decreasing in the area of xylose before and after receiving yeast respectively 1.87% and 1.41%.Therefore, yeast IP4 has the potential to consume xylose amnd purify the XOS. 
 Keywords: corncobs xylan, IP4 yeast, purification, Streptomyces P26B4 xylanase, xylooligosaccharides

Fates of heavy organics of bio-oil in hydrotreatment: The key challenge in the way from biomass to biofuel.

Heavy organics in bio-oil generally refer to the sugar oligomers and lignin-derivatives. They are important fractions in bio-oil and their effective conversion in hydrotreatment determines carbon yield from biomass or bio-oil to biofuel. Fates of the heavy organics largely determine intrinsic reaction behaviors of bio-oil during hydrotreatment. The heavy organics in bio-oil have high tendency towards polymerization upon thermal treatment, which is one of the main precursors for coke formation and catalyst deactivation. Furthermore, the heavy organics have some other unique characteristics in hydrotreatment such as the steric hindrance for contacting active sites on surface of catalyst. How to effectively convert the heavy organics has been regarded as the bottle-neck issue in hydrotreatment of bio-oil and the key barrier in the roadmap from biomass to biofuels. Thus, this review particularly focuses on the progress in understanding reaction behaviors of the heavy organics in hydrotreatment of bio-oil, a central challenge to be resolved. The results indicated that coke formation from heavy organics in bio-oil remains main obstacle in hydrotreatment and further fundamental studies are required to develop suitable catalyst and process to stabilize the heavy organics in bio-oil. In particular, the mechanism for coke formation from the heavy species of varied chemical family should be clarified and corresponding measures should be developed to tackle high tendency of coking. Techno-economic feasibility should be considered in the first place in development of catalysts or process for tackling the heavy fractions of bio-oil.

Friend or Foe? Impacts of Dietary Xylans, Xylooligosaccharides, and Xylanases on Intestinal Health and Growth Performance of Monogastric Animals.

Simple SummaryXylan is naturally present in typical feedstuffs fed to animals and has been shown to cause increased digesta viscosity reducing nutrient digestibility and growth. Xylooligosaccharides are sugar oligomers consisting of xylose units that can be extracted and purified from biomaterials for use as a prebiotic in monogastric feeds. Xylooligosaccharides can also be obtained from the hydrolysis of xylan either in the intestine of the animal or in-vitro through various techniques. The question of xylanase supplementation versus xylooligosaccharide supplementation as well as symbiosis of both on the intestinal health and performance of monogastric livestock is still up for debate. Xylanase inhibitors present in common cereal grains provide yet another obstacle to overcome and are found to be highly variable. As the fear of antibiotic resistance increases, novel approaches to improve growth performance and enhance intestinal health without the use of antibiotics also increase. The aim of this article is to review the structural difference and its impact on xylan in feeds, classification and the use of various xylanases, as well as the production and use of xylooligosaccharides for the physiological effects on intestinal health and growth performance of monogastric animals.This paper discusses the structural difference and role of xylan, procedures involved in the production of xylooligosaccharides (XOS), and their implementation into animal feeds. Xylan is non-starch polysaccharides that share a β-(1-4)-linked xylopyranose backbone as a common feature. Due to the myriad of residues that can be substituted on the polymers within the xylan family, more anti-nutritional factors are associated with certain types of xylan than others. XOS are sugar oligomers extracted from xylan-containing lignocellulosic materials, such as crop residues, wood, and herbaceous biomass, that possess prebiotic effects. XOS can also be produced in the intestine of monogastric animals to some extent when exogenous enzymes, such as xylanase, are added to the feed. Xylanase supplementation is a common practice within both swine and poultry production to reduce intestinal viscosity and improve digestive utilization of nutrients. The efficacy of xylanase supplementation varies widely due a number of factors, one of which being the presence of xylanase inhibitors present in common feedstuffs. The use of prebiotics in animal feeding is gaining popularity as producers look to accelerate growth rate, enhance intestinal health, and improve other production parameters in an attempt to provide a safe and sustainable food product. Available research on the impact of xylan, XOS, as well as xylanase on the growth and health of swine and poultry, is also summarized. The response to xylanase supplementation in swine and poultry feeds is highly variable and whether the benefits are a result of nutrient release from NSP, reduction in digesta viscosity, production of short chain xylooligosaccharides or a combination of these is still in question. XOS supplementation seems to benefit both swine and poultry at various stages of production, as well as varying levels of XOS purity and degree of polymerization; however, further research is needed to elucidate the ideal dosage, purity, and degree of polymerization needed to confer benefits on intestinal health and performance in each respective species.

Effect of Severity Factor on the Subcritical Water and Enzymatic Hydrolysis of Coconut Husk for Reducing Sugar Production

Preventing the further degradation of monomeric or oligomeric sugar into by-product during biomass conversion is one of the challenges for fermentable sugar production. In this study, the performance of subcritical water (SCW) and enzymatic hydrolysis of coconut husk toward reducing sugar production was investigated using a severity factor (SF) approach. Furthermore, the optimal condition of SCW was optimized using response surface methodology (RSM), where the composition changes of lignocellulose and sugar yield as responses. From the results, at low SF of SCW, sugar yield escalated as increasing SF value. In the enzymatic hydrolysis process, the effect of SCW pressure is a significant factor enhancing sugar yield. A maximum total sugar yield was attained on the mild SF condition of 2.86. From this work, it was known that the SF approach is sufficient parameter to evaluate the SCW and enzymatic hydrolysis of coconut husk. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).