Commercial Xylanase Research Articles

Synergistic microwave and acidic deep eutectic solvent-based pretreatment of Theobroma cacao pod husk biomass for xylooligosaccharides production

The bioconversion of lignocellulosic biomass into novel bioproducts is crucial for sustainable biorefineries, providing an integrated solution for circular economy objectives. The current study investigated a novel microwave-assisted acidic deep eutectic solvent (DES) pretreatment of waste cocoa pod husk (CPH) biomass to extract xylooligosaccharides (XOS). The sequential DES (choline chloride/citric acid, molar ratio 1:1) and microwave (450W) pretreatment of CPH biomass was effective in 67.3% xylan removal with a 52% XOS yield from total xylan. Among different XOS of varying degrees of polymerization, a higher xylobiose content corresponding to 69.3% of the total XOS (68.22 mg/g CPH) from liquid fraction was observed. Enzymatic hydrolysis of residual xylan from pretreated CPH biomass with low commercial xylanase (10 IU/g) concentration yielded 24.2% XOS. The MW-ChCl/citric acid synergistic pretreatment approach holds great promise for developing a cost-effective and environmentally friendly method contributing to the sustainable production of XOS from agricultural waste streams.

Funcionalidade nutricional do complexo xilanolítico obtida de Aspergillus japonicus var. aculeatus UFMS 48.136 em dietas para suínos

Abstract The objective of this study was to evaluate the nutritional functionality of the xylanolytic complex produced from Aspergillus japonicus var. aculeatus UFMS 48.136 isolated from the Cerrado/ Pantanal biome in Mato Grosso do Sul, compared to commercial xylanase, in swine diets. Sixteen barrows were used, with an initial weight of 64.23 ± 10.5 kg, distributed in a randomized block experimental design, with four diets: control, formulated according to nutritional recommendations; negative control, formulated with a reduction of 100 Kcal / kg of metabolizable energy (ME); negative control + xylanase Cerrado / Pantanal; negative control + commercial xylanase; with four repetitions each. The xylanase supplementation provided higher (P<0.05) values of digestible energy (DE), ME, and higher (P<0.05) digestibility of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in relation to the negative control diet, but without differing (P>0.05) from the control diet. The inclusion of xylanases increased (P<0.05) in the coefficients of digestibility (CD) and metabolism of crude energy (CE), DM, OM, CP, EE, NDF, and ADF. There was no difference (P>0.05) in digestibility and CD values between Cerrado/Pantanal and commercial xylanase. The inclusion of xylanases made it possible to reduce 100 Kcal of ME per kilogram of diet. Cerrado/Pantanal xylanases therefore have the same nutritional efficiency as commercial xylanases.

Determination of prebiotic properties of rice bran extract.

This research investigated and compared the prebiotic properties of a rice bran extract obtained through commercial xylanase extraction in comparison with water extraction. Prebiotic properties were evaluated by probiotic growth stimulation (Lacticaseibacillus casei and Lactiplantibacillus plantarum) and gastrointestinal pathogen inhibition (Bacillus cereus and Escherichia coli). The rice bran extract obtained with xylanase (RB1) displayed significantly higher total polysaccharide and total reducing sugar contents than those obtained with water (RB2; p<0.05). After extraction for 30 min, RB1 exhibited the highest total polysaccharide and total reducing sugar contents. HPLC (high performance liquid chromatography) analysis revealed that RB1 primarily contained xylose, while RB2 contained less glucose and lacked other sugar derivatives. RB1 proved effective in stimulating the growth of L. casei and L. plantarum, surpassing even inulin (a commercial prebiotic). Furthermore, it demonstrated a high potential for inhibiting the growth of pathogenic B. cereus and E. coli, comparable to inulin. In contrast, RB2 exhibited lower inhibitory capacity against B. cereus and E. coli.

249 The Impact High Soyhull and Soybean Meal Diet Formulations on Grow-Finish Pig Performance

Abstract The objectives of this study were two-fold in evaluating the effects of soybean meal and soyhulls inclusion level in diets fed to grow-finish pigs on growth performance. Firstly, we compared high soybean meal (minimal crystalline amino acids) vs. crystalline amino acids diet formulations. Secondly, we evaluated the addition of soyhulls and soyhulls plus xylanase to diet formulations. In a complete randomized design, a total of 463 grower pigs (BW of 28.4 ± 5.6 kg) were randomly assigned to one of four dietary treatments (n = 12 pens/treatment; 9 – 11 pigs/pen). Within each phase, dietary treatments were formulated to the same SID Lys:ME, and to meet or exceed nutrient recommendations (NRC, 2012) and were fed over three phases consisting of: 1) corn soybean-meal based diet formulated with crystalline amino acids (CON); 2) corn soybean-meal based diet formulated to meet AA requirements via soybean-meal with limited crystalline amino acids (HSBM); 3) As diet #1 with 15% soyhulls (SH); and 4) As diet #3 + commercial xylanase enzyme (SH+X). Diets were formulated with to a SID Lys:ME of 3.26, 2.46, and 1.95 in phase 1, 2, and 3, respectively. Pig BW and pen feed disappearance were recorded at phase change to calculate ADG, ADFI, and feed efficiency (G:F) over the study duration of 95 days. All data were analyzed using the PROC MIXED of SAS 9.4 with pen as the experimental unit and the model included the fixed effect of treatment with least squares means reported. There were no differences (P &amp;gt; 0.05) amongst treatments in phase 1 for any growth performance measures. There was an increase in ADFI of pigs fed SH and SH+X when compared with CON and HSBM (P &amp;lt; 0.05) in phase 2 (P2; 2.89 and 2.82 vs. 2.75 and 2.73 kg/d, respectively) and phase 3 (P3; 3.42 and 3.40 vs. 3.18 and 3.28 kg/d, respectively). However, no differences in ADG or G:F (P &amp;gt; 0.05) compared with CON were reported in P2 or P3. Overall, there were no differences in ADG (P &amp;gt; 0.05) between treatments. Pigs fed SH and SH+X had an increase ADFI compared with CON and HSBM (2.84 and 2.83 vs. 2.68 and 2.71 kg/d, respectively; P &amp;lt; 0.05) and a decrease in G:F when fed SH; however, no differences between CON, HSBM, and SH+X (0.38 vs. 0.40, 0.40, and 0.39, respectively; P &amp;gt; 0.05). In conclusion, there were no negative growth performance effects of feeding a diet containing minimal crystalline amino acids and meeting the requirement of the pigs via soybean meal. Further, there was an increase in feed intake when pigs were fed a diet containing 15% soyhulls, regardless of if there was an addition of xylanase.

The effect of different wheat varieties and exogenous xylanase on bird performance and utilization of energy and nutrients

The aims of the present study were to first, determine the xylan fractions of 10 different wheat cultivar samples and their response to treatment by the same commercial xylanase enzyme preparation. Second, use information obtained to select 5 of the wheats for use within a feeding experiment to determine whether the rate of xylan release can be used to predict the feeding value of the wheats when diets have been supplemented with xylanase. Treatment of 10 different wheat varieties by the same enzyme resulted in varying levels of hydrolysis. Soluble xylan content ranged from 7.85 to 14.40 and 3.20 to 5.13 (mg/g) when treated with and without xylanase, respectively. Oligosaccharide content ranged from 0.34 to 1.58 and 0.05 to 0.54 (mg/g) when treated with and without xylanase, respectively. Five of the 10 wheats were then selected based on the determined xylan fractions to use within a feeding experiment. A total of 360 male Ross 308 broilers were randomly allocated to 60 raised floor pens. A soybean meal (SBM) balancer feed was formulated to contain 12.07 MJ/kg apparent metabolizable energy (AME) and 392.9 g/kg crude protein (CP). Five diets were prepared by mixing 630 g/kg of each of the 5 experimental wheats with 370 g/kg of the balancer. Each diet was split into 2, one of which was supplemented with 100 g/MT of Econase XT (223,000 BXU/g), resulting in a total of 10 diets. The birds were fed the diets from 0 to 28 d of age. Wheat cultivar had an effect (P=0.044) on feed intake (FI), while the addition of xylanase increased (P < 0.05) weight gain (WG) and improved feed conversion ratio (FCR). Various interactions were observed (P < 0.05) between wheat cultivars and xylanase for AME and nutrient utilization. This study suggests that wheats treated with the same xylanase, differ in their susceptibility to release soluble xylan and oligosaccharides, which may partially explain the varying performance and nutrient digestibility responses noted in the literature.

Structure and function characterization of the α-L-arabinofuranosidase from the white-rot fungus Trametes hirsuta

α-L-Arabinofuranosidases (Abfs) play a crucial role in the degradation of hemicelluloses, especially arabinoxylans (AX). Most of the available characterized Abfs are from bacteria, while fungi, as natural decomposers, contain Abfs with little attention given. An arabinofuranosidase (ThAbf1), belonging to the glycoside hydrolase 51 (GH51) family, from the genome of the white-rot fungus Trametes hirsuta, was recombinantly expressed, characterized, and functionally determined. The general biochemical properties showed that the optimal conditions for ThAbf1 were pH 6.0 and 50°C. In substrate kinetics assays, ThAbf1 preferred small fragment arabinoxylo-oligosaccharides (AXOS) and could surprisingly hydrolyze di-substituted 23,33-di-L-arabinofuranosyl-xylotriose (A2,3XX). It also synergized with commercial xylanase (XYL) and increased the saccharification efficiency of arabinoxylan. The crystal structure of ThAbf1 indicated the presence of an adjacent cavity next to the catalytic pocket which led to the ability of ThAbf1 to degrade di-substituted AXOS. The narrow binding pocket prevents ThAbf1 from binding larger substrates. These findings have strengthened our understanding of the catalytic mechanism of GH51 family Abfs and provided a theoretical foundation for the development of more efficient and versatile Abfs to accelerate the degradation and biotransformation of hemicellulose in biomass. KEY POINTS: • ThAbf1 from Trametes hirsuta degraded di-substituted arabinoxylo-oligosaccharide. • ThAbf1 performed detailed biochemical characterization and kinetics. • ThAbf1 structure has been obtained to illustrate the substrate specificity.

Use of corn cob through xylan extraction and its potential use as a substrate for the quantification of xylanase enzymatic activity

In Mexico, it is estimated that the amount of residues produced by the planting of the ten main crops is approximately 45 million tons of dry matter, of which just over 25 million tons are corn cob. The corn cob contains large amounts of hemicellulose, mainly composed of xylan, which can have various industrial uses. For this reason, in the present study, fresh and dry corn cob was used with two particle sizes: 0.105 mm and 0.42 mm, to carry out an exhaustive alkaline extraction of xylan and where eight fractions of hemicelluloses extracts were obtained. Each of the fractions were subjected to enzymatic hydrolysis for eight hours with a commercial xylanase (Livanol Devisco 1500) and as internal control, beechwood xylan (Sigma Aldrich, X4252) was used, of which only 6.9 ± 2.25 g/L were released. reducing sugars. It was found that the fractions from the steam treatment and the fraction from the alkaline extraction precipitated with alcohol, both for fresh corn cob, were released a quantity of reducing sugars very similar to commercial xylan with 7.10 ± 2.02 and 7.24 ± 0.37 g/L, respectively. Finally, it was possible to determine that although the 8 fractions obtained in the present study can be used as substrates to determine the xylanase enzymatic activity, the best was the fraction of the alkaline extraction since 0.236 ± 0.03 IU/mL were quantified, while for the commercial substrate (beechwood xylan) an activity of 0.287 ± 0.01 IU/mL was obtained.

A novel cold-active GH8 xylanase from cellulolytic myxobacterium and its application in food industry

Although xylanase have a wide range of applications, cold-active xylanases have received less attention. In this study, a novel glycoside hydrolase family 8 (GH8) xylanase from Sorangium cellulosum with high activity at low temperatures was identified. The recombinant xylanase (XynSc8) was most active at 50 °C, demonstrating 20% of its maximum activity and strict substrate specificity towards beechwood and corncob xylan at 4 °C with Vmax values of 968.65 and 1521.13 μmol/mg/min, respectively. Mesophilic XynSc8 was active at a broad range of pH and hydrolyzed beechwood and corncob xylan into xylooligosaccharides (XOS) with degree of polymerization greater than 3. Moreover, incorporation of XynSc8 (0.05–0.2 mg/kg flour) provided remarkable improvement (28–30%) in bread specific volume and textural characteristics of bread compared to commercial xylanase. This is the first report on a novel cold-adapted GH8 xylanase from myxobacteria, suggesting that XynSc8 may be a promising candidate suitable for bread making.

Evaluation of Original and Enzyme-Modified Fique Fibers as an Azo Dye Biosorbent Material

As natural fibers, low-cost biosorbents have proven to be an effective and clean tool to remove textile dyes from wastewater. In this research, the Reactive Black 5 removal ability of original and enzyme-modified natural fibers were assessed. A fiber extracted from a Colombian fique plant (Furcraea sp.) was employed. The effects of fique fiber protonation with different solvents and dye solution pH on RB5 removal were evaluated. The biosorbent chemical composition was modified using the commercial enzymes pectinase, ligninase, and xylanase. The point of zero charge (PZC) of the original and modified material was measured, and the dye removal capacity of the three enzyme-modified fibers was determined. Fiber protonation with 0.1 M HCl and a dye solution with pH of 2.4 increased the RB5 elimination to 49.1%. The change in the fiber chemical composition led to a reduction in the PZC from 5.5 to a 4.7–4.9 range. Pectinase-pretreated fique fibers presented the highest dye removal of 66.29%, representing a 36% increase in RB5 dye removal. Although the original fique fiber showed RB5 dye removal ability, its enzymatic modification changed the charge distribution on the fiber surface, improving the capture of dye molecules. Enzyme modification can be applied to obtain new functionalities for plant fibers as biosorbent materials.

Dietary Chlorella vulgaris with a specific enzyme mixture enriches pork in potassium and improves its sodium to potassium ratio

PurposeThe purpose of this study was to assess the effect of dietary inclusion of 5% Chlorella vulgaris, individually or supplemented with two carbohydrase mixtures, on pork's mineral profile (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorous, sulfur and zinc).Design/methodology/approachForty male finishing pigs were assigned to four dietary treatments: cereal and soybean meal-based diet (control), control diet with 5% microalga (CCV), CCV diet supplemented with 0.005% of a commercial xylanase and β-glucanase-based complex and CCV diet supplemented with 0.01% of a mixture of four carbohydrate-active enzymes. Pigs were slaughtered after 41 ± 7.8 days of trial and the mineral composition of longissimus lumborum muscle was analyzed using inductively coupled plasma–optical emission spectrometry.FindingsWhen C. vulgaris was supplemented with a four-CAZyme mixture, an increase of total minerals in meat was found due to a higher content of potassium, which led to a decrease of sodium to potassium ratio in pork. However, CCV treatment decreased the amount of calcium and manganese in meat, which was likely due to a lower bioavailability of these minerals in the diet.Originality/valueConsidering the imbalance of sodium and potassium in most Western diets and the increasing occurrence of cardiovascular diseases in the population, the improvement of meat quality caused by a reduction of sodium to potassium ratio might help to reduce the prevalence of high blood pressure and cardiovascular diseases, having thus benefits for consumers' health.

Improved Release of Monosaccharides and Ferulic Acid Using Enzyme Blends From Aspergillus Niger and Eupenicillium Parvum.

Supplementing commercial xylanase and cellulase with selected debranching enzymes only resulted in slight enhancement of the enzymatic hydrolysis of wheat bran autohydrolysis residues (WBAR) which was obtained at 160°C over a 30-min period of autohdyrolysis, while a blend of enzymes from Aspergillus niger and Eupenicillium parvum achieved synergistic efficacy in this context. Using an equal mixture blend of these enzymes at a 0.5% (w/w) enzyme loading dosage with the addition of ferulic acid esterase (1 U/g substrate), the obtained hydrolysis yields were desirable, including 84.98% of glucose, 84.74% of xylose, 80.24% of arabinose, and 80.86% of ferulic acid. Following further separation using an HP-20 resin, the final ferulic acid recovery levels were as high as 62.5% of the esterified ferulic acid present within the initial WBAR input. Together, these data suggest that a combination of autohydrolysis and enzymatic hydrolysis using crude enzyme blends can efficiently achieve wheat bran enzymatic saccharification and associated ferulic acid release.

Microwave-assisted enzymatic hydrolysis to produce xylooligosaccharides from rice husk alkali-soluble arabinoxylan

The prebiotic properties of xylooligosaccharides (XOS) and arabino-xylooligosaccharides (AXOS) produced from rice husk (RH) using microwave treatment combined with enzymatic hydrolysis were evaluated. The RH was subjected to microwave pretreatment at 140, 160 and 180 °C for 5, 10 and 15 min to obtain crude arabinoxylan (AX). Increasing microwave pretreatment time increased sugar content. Crude AX was extracted with 2% (w/v) sodium hydroxide at 25 °C for 24 h and used as a substrate for XOS production by commercial xylanases. Results showed that oligosaccharides produced by Pentopan Mono BG and Ultraflo Max provided xylobiose and xylotriose as the main products. AXOS was also present in the oligosaccharides that promoted growth of Lactobacillus spp. and resisted degradation by over 70% after exposure to simulated human digestion.

Xylose Release from Sunflower Stalk by Coupling Autohydrolysis and Enzymatic Post-Hydrolysis

PurposeIn this study, to obtain xylose-based fermentation media from autohydrolysis liquors of sunflower stalk by using commercial xylanase formulation was aimed. Xylose is generally produced from xylan by diluted acid hydrolysis that causes the formation of some unwanted compounds during the process. As an alternative to dilute acid hydrolysis method, enzymatic hydrolysis of xylan can provide more specific hydrolysis under moderate conditions and does not cause the formation of undesirable compounds.MethodsXylose production was carried out with Trichoderma longibrachiatum xylanase on solubilized xylan form of sunflower stalk, which was hydrothermally pretreated for 1 h at 160 °C. The effects of substrate concentration and enzyme activity were investigated for the production of xylose. To obtain a high xylose yield and selectivity, the optimization study was conducted by the response surface methodology.ResultsThe optimum substrate concentration and enzyme activity were found as 60 mg ds/mL CAL and 234 U/mL, respectively. Under the optimum condition, xylose yield and selectivity were found to be 69.5% and 8.2 g/g, respectively.ConlusionThis study showed that xylose could be produce with a high yield without requiring a neutralization process and corrosive chemical reagent apart from water.Graphic Abstract

Improved Production of Xylanase in Pichia pastoris and Its Application in Xylose Production From Xylan

Xylanases with high specific activity has been focused with great interest as a useful enzyme in biomass utilization. The production of recombinant GH11 xylanase (MYCTH_56237) from Myceliophthora thermophila has been improved through N-terminal signal peptide engineering in P. pastoris. The production of newly recombinant xylanase (termed Mtxyn11C) was improved from 442.53 to 490.7 U/mL, through a replacement of α-factor signal peptide with the native xylanase signal peptide segment (MVSVKAVLLLGAAGTTLA) in P. pastoris. Scaling up of Mtxyn11C production in a 7.5 L fermentor was improved to the maximal production rate of 2503 U/mL. In this study, the degradation efficiency of Mtxyn11C was further examined. Analysis of the hydrolytic mode of action towards the birchwood xylan (BWX) revealed that Mtxyn11C was clearly more effective than commercial xylanase and degrades xylan into xylooligosaccharides (xylobiose, xylotriose, xylotetraose). More importantly, Mtxyn11C in combination with a single multifunctional xylanolytic enzyme, improved the hydrolysis of BWX into single xylose by 40%. Altogether, this study provided strategies for improved production of xylanase together with rapid conversion of xylose from BWX, which provides sustainable, cost-effective and environmental friendly approaches to produce xylose/XOSs for biomass energy or biofuels production.

Xylanases in diets with alternative feeds and energy reduction in commercial layers

The use of alternative ingredients has been increasing in a continuing attempt to reduce production costs, along with the use of additives, such as carbohydrases, for their possible positive effects on nutrient metabolization by layers. Thus, this study aimed to evaluate the effects of different xylanases in diets with reduced metabolizable energy (ME) and the inclusion of alternative ingredients on the metabolizability of nutrients in diets for commercial laying hens, by conducting two metabolism tests. In the first trial,100 layers hens were distributed in a fully randomized 2 × 2 + 1 factorial design (two metabolizable energy reductions × two xylanases, plus one control diet). In the second assay,140 layer hens were distributed in a fully randomized 2 × 3 + 2 factor design (two xylanases× three ingredients, plus two control diets, positive and negative). It was concluded that supplementation with pantanal xylanase improved the metabolizability of nutrients in corn-based diets and soybean meal for light commercial layers, allowing for a reduction of up to 200 kcal/kg of ME in the diets. Xylanases are more effective on wheat bran enabling a decrease of 150 kcal/kg of ME in commercial laying diets without affecting nutrient metabolizability. The action of pantanal xylanase in diets containing fibrous ingredients was similar to that of commercial xylanase.

Silage quality and biogas production from Spartina pectinata L. fermented with a novel xylan-degrading strain of Lactobacillus buchneri M B/00077

The aim of the current study was to determine the ability of the Lactobacillus buchneri M B/00077 strain to degrade xylan, its impact on the quality of silage made from the lignocellulosic biomass of Spartina pectinata L., as well as the efficiency of biogas production. In the model in vitro conditions the L. buchneri M B/00077 strain was able to grow in a medium using xylan as the sole source of carbon, and xylanolytic activity was detected in the post-culture medium. In the L. buchneri M B/00077 genome, genes encoding endo-1,4-xylanase and β-xylosidase were identified. The silages prepared using L. buchneri M B/00077 were characterized by a higher concentration of acetic and propionic acids compared to the controls or the silages prepared with the addition of commercial xylanase. The addition of bacteria increased the efficiency of biogas production. From the silages treated with L. buchneri M B/00077, 10% and 20% more biogas was obtained than from the controls and the silages treated with commercial xylanase, respectively. The results of the current study indicated the strain L. buchneri M B/00077 as being a promising candidate for further application in the field of pretreatment of lignocellulosic biomass.

Characterization of Feruloyl Esterase from Bacillus pumilus SK52.001 and Its Application in Ferulic Acid Production from De-Starched Wheat Bran.

Feruloyl esterase (FAE; EC 3.1.1.73) catalyzes the hydrolysis of the 4-hydroxy-3-methoxycinnamoyl group in an esterified sugar to assist in waste biomass degradation or to release ferulic acid (FA). An FAE-producing strain was isolated from humus soil samples and identified as Bacillus pumilus SK52.001. The BpFAE gene from B. pumilus SK52.001 was speculated and heterogeneously expressed in Bacillus subtilis WB800 for the first time. The enzyme exists as a monomer with 303 amino acids and a molecular mass of 33.6 kDa. Its specific activity was 377.9 ± 10.3 U/(mg protein), using methyl ferulate as a substrate. It displays an optimal alkaline pH of 9.0, an optimal temperature of 50 °C, and half-lives of 1434, 327, 235, and 68 min at 50, 55, 60, and 65 °C, respectively. Moreover, the purified BpFAE released 4.98% FA of the alkali-acidic extractable FA from de-starched wheat bran (DSWB). When the DSWB was enzymatically degraded by the synergistic effect of the BpFAE and commercial xylanase, the FA amount reached 49.47%. It suggested that the alkaline BpFAE from B. pumilus SK52.001, which was heterologously expressed in B. subtilis WB800, possesses great potential for biomass degradation and achieving high-added value FA production from food by-products.

Effects of Enzyme Loading, Incubation Time and Incubation Temperature on Sawdust Hydrolysis by Locally Produced Bacterial Xylanase

The present study aims to investigate the enzymatic hydrolysis conditions of bacterial xylanase on alternative cheaper substrate which is hardwood sawdust (SD) in order to produce reducing sugars (xylose). The bacterial xylanase was produced and secreted from the Bacillus sp. The wood industry in Malaysia has become a major source of foreign exchange across the globe for developing the countries. Therefore, more wood residues (sawdust) are produced during the logging and processing of wood. Most of the sawdust will be disposed into the landfills. In actual, the sawdust can be utilised into more valuable products such as in producing reducing sugars. Thus, previous researches have studied on xylose production from wooden sawdust using commercial xylanases, but only few with the bacterial xylanase. Therefore, a study on the best conditions of enzymatic hydrolysis in producing xylose from sawdust using bacterial xylanase is essential. Prior to the enzymatic hydrolysis, the hardwood sawdust was pre-treated by autoclave at 121°C for 20 min in order to breakdown the lignin linkage and obtain the hemicellulosic xylan (delignification). The enzymatic hydrolysis conditions such as enzyme loading, incubation time and incubation temperature were experimented by One-Factor-At-Time (OFAT) method. Based on the experiment, the fifth cycle pre-treated autoclaved sawdust showed 5.5-fold higher than the untreated sawdust. The best enzymatic hydrolysis conditions for xylose production were enzyme loading of 1.4%, incubation time of 30 min, and incubation temperature of 56.9 °C. These conditions also succeeded in producing 2.5-fold higher xylose than the one without the enzymatic hydrolysis. &#x0D;

A novel thermostable xylanase from Geobacillus vulcani GS90: Production, biochemical characterization, and its comparative application in fruit juice enrichment.

Xylanases have great attention to act as a potential role in agro-industrial processes. In this study, production, characterization, and fruit juice application of novel xylanase from thermophilic Geobacillus vulcani GS90 (GvXyl) were performed. GvXyl was purified via acetone precipitation and gel-filtration chromatography. The results showed that GvXyl had 1,671.4U/mg of specific activity and optimally worked at pH 8 and 55°C. It was also active in a wide pH (3-9) and temperature (30-90ºC) ranges. GvXyl was highly stable at 90ºC and relatively stable at pH 3-9. The kinetic parameters of GvXyl were obtained as Km , Vmax , and kcat ; 10.2mg/ml, 4,104µmolmin-1 mg-1 , and 3,542.6s-1 , respectively. GvXyl had higher action than commercial xylanase in fruit juice enrichment. These results revealed that GvXyl might possess a potential influence in fruit juice processing because of its high specific activity and great thermal stability. PRACTICAL APPLICATIONS: Polysaccharides include starch, pectin, and hemicellulose create problems by lowering fruit juice quality in beverages. To overcome this problem, various clarification processes might be applied to natural fruit juices. Even though chemicals are widely used for this purpose, recently enzymes including xylanases are preferred for obtaining high-quality products. In this study, we reported the production and biochemical characterization of novel thermostable xylanase from thermophilic G. vulcani GS90 (GvXyl). Also, apple and orange juice enrichment were performed with the novel xylanase to increase the quality in terms of yield, clarity, and reducing sugar substance. The improved quality features of apple and orange juices with GvXyl was then compared to commercially available β-1,4-xylanase. The results revealed that GvXyl might possess a potential influence in fruit juice processing because of its high specific activity and great thermal stability.

Production of Xyloligosaccharides from Rice Straw by Microwave-assisted Enzymatic Hydrolysis and Evaluation of Their Prebiotic Properties

Rice straw (RS) is a by-product from rice production process. It is rich in cellulose, hemicellulose and lignin. RS hemicellulose mainly composes of arabinoxylan (AX). This research aimed to investigate the potential of microwave-pretreatment in AX extraction from RS and substrate to produce xylooligosaccharides (XOS) via enzymatic hydrolysis. The extractive-free RS was pretreated by microwave process at 160°C for 5-15 min, then the AX was extracted with 4% sodium hydroxide. The total sugar and reducing sugar content of AX exhibited that increasing microwave-pretreatment time increased the yield of AX. The highest AX content was found at 160°C for 10 min as 7.73%, reducing sugar content of 11.89 mg/g, and total sugar of 165.85 mg/g. The crude AX obtained by microwave-pretreatment was then used as a substrate for XOS production by two commercial xylanases of Pentopan mono BG (BG) and Ultraflo Max (UM), at the enzyme concentration of 50-300 U/g AX (50°C, pH 6.0) for 24 h.The reducing sugar content and sugar profiles were monitored by DNS assay,and thin layer chromatography (TLC) which revealed that BG 50 U/g at 12 h andUM 50 U/g at 24 h showed the promising reducing sugar of 16.4 and 25.44 mg/g,respectively. The composition of XOS derived from RS (RS-XOS) prepared by BGwas xylobiose (X2), xylotriose (X3), xylotretraose (X4), and xylopentaose (X5)while by UM was xylobiose (X2), xylotriose (X3) and xylotretraose (X5). Moreover,XOS produced by BG contained very low amount of xylose (X1). In addition, theRS-XOS could the growth of Lactobacillus brevis greater than commercial XOS.