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|Storage Temperature:||Below -10oC|
|Stability:||> 10 years under recommended storage conditions|
|Substrate For (Enzyme):||endo-1,4-β-Xylanase|
High purity Xylopentaose for use in research, biochemical enzyme assays and in vitro diagnostic analysis.
(Trichoderma longibrachiatum) E-XYLAA - endo-1,4-β-Xylanase (Aspergillus aculeatus) E-XYAN4 - endo-1,4-β-Xylanase M4 (Aspergillus niger) E-XYRU6 - endo-1,4-β-Xylanase (rumen microorganism) E-XYNAP - endo-1,4-β-Xylanase (Aeromonas punctata) E-XYNBS - endo-1,4-β-Xylanase
(Bacillus stearothermophilus T6) E-XYNACJ - endo-1,4-β-Xylanase (Cellvibrio japonicus) E-XYNBCM - endo-1,4-β-Xylanase (Cellvibrio mixtus) E-XYLNP - endo-1,4-β-Xylanase (Neocallimastix patriciarum) E-XYLATM - endo-1,4-β-Xylanase (Thermotoga maritima) E-BXSEBP - β-Xylosidase (Bacillus pumilus) E-BXSR-1KU - β-D-Xylosidase (Selenomonas ruminantium)
McCleary, B. V. & McGeough, P. (2015). Appl. Biochem. Biotechnol., 177(5), 1152-1163.
The most commonly used method for the measurement of the level of endo-xylanase in commercial enzyme preparations is the 3,5-dinitrosalicylic acid (DNS) reducing sugar method with birchwood xylan as substrate. It is well known that with the DNS method, much higher enzyme activity values are obtained than with the Nelson-Somogyi (NS) reducing sugar method. In this paper, we have compared the DNS and NS reducing sugar assays using a range of xylan-type substrates and accurately compared the molar response factors for xylose and a range of xylo-oligosaccharides. Purified beechwood xylan or wheat arabinoxylan is shown to be a suitable replacement for birchwood xylan which is no longer commercially available, and it is clearly demonstrated that the DNS method grossly overestimates endo-xylanase activity. Unlike the DNS assay, the NS assay gave the equivalent colour response with equimolar amounts of xylose, xylobiose, xylotriose and xylotetraose demonstrating that it accurately measures the quantity of glycosidic bonds cleaved by the endo-xylanase. The authors strongly recommend cessation of the use of the DNS assay for measurement of endo-xylanase due to the fact that the values obtained are grossly overestimated due to secondary reactions in colour development.Hide Abstract
Versatile high resolution oligosaccharide microarrays for plant glycobiology and cell wall research.
Pedersen, H. L., Fangel, J. U., McCleary, B., Ruzanski, C., Rydahl, M. G., Ralet, M. C., Farkas, V., Von Schantz, L., Marcus, S. E., Andersen, M.C. F., Field, R., Ohlin, M., Knox, J. P., Clausen, M. H. & Willats, W. G. T. (2012). Journal of Biological Chemistry, 287(47), 39429-39438.
Microarrays are powerful tools for high throughput analysis, and hundreds or thousands of molecular interactions can be assessed simultaneously using very small amounts of analytes. Nucleotide microarrays are well established in plant research, but carbohydrate microarrays are much less established, and one reason for this is a lack of suitable glycans with which to populate arrays. Polysaccharide microarrays are relatively easy to produce because of the ease of immobilizing large polymers noncovalently onto a variety of microarray surfaces, but they lack analytical resolution because polysaccharides often contain multiple distinct carbohydrate substructures. Microarrays of defined oligosaccharides potentially overcome this problem but are harder to produce because oligosaccharides usually require coupling prior to immobilization. We have assembled a library of well characterized plant oligosaccharides produced either by partial hydrolysis from polysaccharides or by de novo chemical synthesis. Once coupled to protein, these neoglycoconjugates are versatile reagents that can be printed as microarrays onto a variety of slide types and membranes. We show that these microarrays are suitable for the high throughput characterization of the recognition capabilities of monoclonal antibodies, carbohydrate-binding modules, and other oligosaccharide-binding proteins of biological significance and also that they have potential for the characterization of carbohydrate-active enzymes.Hide Abstract
Improved development in magnetic Xyl-CLEAs technology for biotransformation of agro-industrial by-products through the use of a novel macromolecular cross-linker.
Hero, J. S., Morales, A. H., Perotti, N. I., Romero, C. M. & Martinez, M. A. (2020). Reactive and Functional Polymers, 154, 104676.
Cross-Linked Enzyme Aggregates (CLEAs) technologies for enzyme immobilization are influenced by mass transference problems as the degree of molecular crosslinking achieved strongly affects the enzyme exposure to the substrates. Therefore, this work seeks to improve the accessibility of high molecular weight substrates by using macromolecular cross-linkers to the synthesis of a xylanolytic biocatalyst. After confirming that commercial polymers used as macromolecular cross-linkers significantly upgraded the xylanase activity from a crude preparation, a novel biopolymer/amyloid protein complex (BPAP) extracted from a microbial biofilm was used producing a remarkable recovery (83%) of the enzyme activity. A response surface methodology was applied to contrast the features of a previously developed biocatalyst with glutaraldehyde (GA@Xyl-CLEAs) and a novel one synthesized with BPAP combined with functionalized magnetic nanoparticles: mBPAP@Xyl-CLEAs. It was observed that the crosslinking agent used was the factor that most affected the enzyme activity. Also, the mBPAP system showed a similar and higher hydrolytic activity than those synthesized with GA, which was not affected by the mNPs/protein ratio. Finally, the mBPAP@Xyl-CLEAs were successfully tested for xylooligosaccharides production from agroindustrial-derived substrates, making this technology a promising practice to obtain green and suitable biocatalysts.Hide Abstract
An integrated process to produce prebiotic xylooligosaccharides by autohydrolysis, nanofiltration and endo-xylanase from alkali-extracted xylan.
Lian, Z., Wang, Y., Luo, J., Lai, C., Yong, Q., & Yu, S. (2020). Bioresource Technology, 314, 123685.
Alkali-extracted xylan from lignocellulosics is a promising feedstock for production of prebiotic xylooligosaccharides (XOS). An integrated process was established combining autohydrolysis, nanofiltration and xylanase hydrolysis. Results show that after autohydrolysis 48.37% of xylan was degraded into oligomers and dissolved into the autohydrolysate, of which 57.83% were XOS. By-products and xylose were removed by nanofiltration with discontinuous diafiltration, while high recovery yields of XOS (84.15%) and xylan (87.45%) were obtained. High yields of XOS were obtained by adding xylanase to the autohydrolysates; after enzymatic hydrolysis an XOS yield of 96-98% was obtained. The enzymatic hydrolysates showed positive prebiotic effects on B. adolescentis with an increase in cell concentration by 4.8-fold after fermentation for 24 h. The main products were short-chain fatty acids with carbon balanced during the whole fermentation process. This integrated strategy resulted in a final XOS conversion of 41.22% contrasted to the initial xylan in raw alkali-extracted xylan.Hide Abstract
Enzyme synergy for the production of arabinoxylo-oligosaccharides from highly substituted arabinoxylan and evaluation of their prebiotic potential.
Bhattacharya, A., Ruthes, A., Vilaplana, F., Karlsson, E. N., Adlecreutz, P. & Stålbrand, H. (2020). LWT, 131, 109762.
Wheat bran arabinoxylan can be converted by enzymatic hydrolysis into short arabinoxylo-oligosaccharides (AXOS) with prebiotic potential. Alkali extraction of arabinoxylan from wheat-bran offers advantages in terms of yield and results in arabinoxylan with highly-substituted regions which has been a challenge to hydrolyse using endoxylanases. We show that this hurdle can be overcome by selecting an arabinoxylanase that attacks these regions. The yield of AXOS can be increased by enzyme synergy, involving the hydrolysis of some arabinoxylan side groups. Thus, arabinoxylanase (CtXyl5At) from Clostridium thermocellum, belonging to subfamily 34 of glycoside hydrolase (GH) family 5 was investigated pertaining to its specificity for highly-substituted regions in the arabinoxylan-backbone. CtXyl5At preferentially hydrolysed the water-soluble fraction of alkali-extracted arabinoxylan. AXOS with DP 2-4 were determined as major products from CtXyl5At catalyzed hydrolysis. Increase in AXOS yield was observed with enzyme synergy, involving an initial treatment of soluble arabinoxylan with a GH43 α-l-arabinofuranosidase from Bifidobacterium adolescentis termed BaAXHd3 (30°C, 6h), followed by hydrolysis with CtXyl5At (50°C, 24h). The prebiotic potential of AXOS was shown by growth analysis using the human gut bacteria Bifidobacterium adolescentis ATCC 15703 and Roseburia hominis DSM 6839. Importantly, AXOS were utilized by the bacteria and short-chain fatty acids were produced.
Enzyme-aided xylan extraction from alkaline-sulfite pretreated sugarcane bagasse and its incorporation onto eucalyptus kraft pulps.
Cornetti, A. A. A., A., Ferraz, A. & Milagres, A. M. (2020). Carbohydrate Research, 108003.
Hemicellulose-rich substrates produced in the lignocellulose biorefinery context can yield macromolecular xylan structures with assorted application in the chemical industry. Xylan presents natural affinity to cellulose and its incorporation onto fibers increases the physical processability of pulp; however, current studies diverge on how molar mass affects xylan interaction with cellulose. In the current work, xylans with varied structural characteristics were prepared from alkaline-sulfite pretreated sugarcane bagasse with aid of an alkaline-active xylanase and selective precipitations using different ethanol concentrations. Prepared xylan fractions, containing low levels of lignin contamination (4-9%) and molar masses ranging from 2.3 kDa to 34 kDa, were incorporated onto eucalyptus pulp fibers up to 4.7 g xylan/100 g pulp. The efficiency of xylan incorporation onto cellulosic fibers was dependent on the xylan structures, where low molar mass and low substitution degree favored high incorporation levels.Hide Abstract
Identification of a Key Enzyme for the Hydrolysis of β-(1→ 3)-xylosyl Linkage in Red Alga Dulse Xylooligosaccharide from Bifidobacterium adolescentis.
Kobayashi, M., Kumagai, Y., Yamamoto, Y., Yasui, H. & Kishimura, H. (2020). Marine Drugs, 18(3), 174.
Red alga dulse possesses a unique xylan, which is composed of a linear β-(1→3)/β-(1→4)-xylosyl linkage. We previously prepared characteristic xylooligosaccharide (DX3, (β-(1→3)-xylosyl-xylobiose)) from dulse. In this study, we evaluated the prebiotic effect of DX3 on enteric bacterium. Although DX3 was utilized by Bacteroides sp. and Bifidobacterium adolescentis, Bacteroides Ksp. grew slowly as compared with β-(1→4)-xylotriose (X3) but B. adolescentis grew similar to X3. Therefore, we aimed to find the key DX3 hydrolysis enzymes in B. adolescentis. From bioinformatics analysis, two enzymes from the glycoside hydrolase family 43 (BAD0423: subfamily 12 and BAD0428: subfamily 11) were selected and expressed in Escherichia coli. BAD0423 hydrolyzed β-(1→3)-xylosyl linkage in DX3 with the specific activity of 2988 mU/mg producing xylose (X1) and xylobiose (X2), and showed low activity on X2 and X3. BAD0428 showed high activity on X2 and X3 producing X1, and the activity of BAD0428 on DX3 was 1298 mU/mg producing X1. Cooperative hydrolysis of DX3 was found in the combination of BAD0423 and BAD0428 producing X1 as the main product. From enzymatic character, hydrolysis of X3 was completed by one enzyme BAD0428, whereas hydrolysis of DX3 needed more than two enzymes.Hide Abstract
High Enzymatic Recovery and Purification of Xylooligosaccharides from Empty Fruit Bunch via Nanofiltration.
Wijaya, H., Sasaki, K., Kahar, P., Rahmani, N., Hermiati, E., Yopi, Y., Ogino, C. Prasetya, B. & Kondo, A. (2020). Processes, 8(5), 619.
Xylooligosaccharides (XOS) are attracting an ever-increasing amount of interest for use as food prebiotics. In this study, we used efficient membrane separation technology to convert lignocellulosic materials into a renewable source of XOS. This study revealed a dual function of nanofiltration membranes by first achieving a high yield of xylobiose (a main component of XOS) from alkali-pretreated empty fruit bunch (EFB) hydrolysate, and then by achieving a high degree of separation for xylose as a monosaccharide product. Alkali pretreatment could increase the xylan content retention of raw EFB from 23.4% to 26.9%, which eventually contributed to higher yields of both xylobiose and xylose. Nanofiltration increased the total amount of XYN10Ks_480 endoxylanase produced from recombinant Streptomyces lividans 1326 without altering its specific activity. Concentrated XYN10Ks_480 endoxylanase was applied to the recovery of both xylobiose and xylose from alkali-pretreated EFB hydrolysate. Xylobiose and xylose yields reached 41.1% and 17.3%, respectively, and when unconcentrated XYN10Ks_480 endoxylanase was applied, those yields reached 35.1% and 8.3%, respectively. The last step in nanofiltration was to separate xylobiose over xylose, and 41.3 g.L−1 xylobiose (90.1% purity over xylose) was achieved. This nanofiltration method should shorten the processes used to obtain XOS as a high-value end product from lignocellulosic biomass.Hide Abstract
Production of xylooligosaccharides from xylan catalyzed by endo-1, 4-β-D-xylanase-immobilized nanoscale carbon, silica and zirconia matrices.
Shivudu, G., Chandraraj, K. & Selvam, P. (2020). Molecular Catalysis, 484, 110745.
Nanoscale materials of carbon, silica and zirconia were used to immobilize a recombinant endo-1, 4-β-D-xylanase (XynC) of B. subtilis KCX006. The adsorption of endo-1, 4-β-D-xylanase on nanomaterials of carbon, silica and zirconia followed the pseudo-second-order kinetic model. The activation energies for adsorption of endoxylanase on carbon, silica and zirconia nanomaterials were 9.94 kJ mol−1, 40.44 kJ mol−1 and 16.33 kJ mol−1 respectively. The recovered activity (RA) of endoxylanase immobilized on carbon, silica and zirconia nanomaterials was in the range of 52%–92%. The endoxylanase immobilized on zirconia nanoparticles showed maximum RA. All immobilized endoxylanase showed optimum activity at pH 6.6 similar to that of free/soluble endoxylanase. But compared to free endoxylanase, all immobilized endoxylanase had broad optimum temperature range (50-65°C) for catalytic activity. The Michaelis-Menten constant (Km) increased for all immobilized endoxylanase due to substrate diffusion limit. The endoxylanase immobilized on above nanomaterials was used repeatedly for XOS production from xylan. All immobilized endoxylanase produced X2-X6 and substituted XOS similar to free endoxylanase from beechwood xylan and extracted crude xylans from sorghum and sugarcane bagasse. The endoxylanase immobilized on above nanoparticles did not lose activity after five batches of repeated use. The results showed that endoxylanase immobilized on carbon, silica and zirconia matrices would be useful for production of XOS by enzyme recycling.Hide Abstract
Modified-dietary fiber from cassava pulp reduces abdominal fat and meat cholesterol contents without affecting growth performance of broiler chickens.
Okrathok, S. & Khempaka, S. (2020). Journal of Applied Poultry Research, 29(1), 229-239.
This study aimed to investigate the effects of modified-dietary fiber from cassava pulp (M-DFCP), mostly classified as insoluble dietary fiber (IDF), as a feed supplement on productive performance, nutrient digestibility, weight of digestive organs, abdominal fat storage, and cholesterol in meat and blood of broiler chickens. A total of 336 one-day-old male broiler chickens (Ross 308) were allocated to 4 groups in 7 replicate pens with 12 chicks each, based on a completely randomized design. Four dietary treatments composed of control and 3 M-DFCP inclusion levels: 0.5, 1.0, and 1.5%. The results showed that M-DFCP showed no negative effects on growth performance in broiler chickens. The inclusion of M-DFCP in diets at 1.0 to 1.5% had positive effects on increased gizzard weight, reduced gizzard pH, and reduced abdominal fat. The M-DFCP at 1.0% can also increase nutrient digestibility (dry matter, organic matter, and ether extract). In addition, the supplementation of M-DFCP at 1.0 to 1.5% in diets represented lower cholesterol in serum, breast and thigh meats, and liver of broiler chickens. In conclusion, these results indicate that M-DFCP can be used as an IDF source in broiler diets. The inclusion of 1.0% M-DFCP in broiler diet has positive effects on enhancing gizzard function, improving nutrient digestibility, and reducing abdominal fat and cholesterol in chicken meat, blood, and liver.Hide Abstract
In vitro versus in situ evaluation of xylan hydrolysis into xylo-oligosaccharides in broiler chicken gastrointestinal tract.
Morgan, N. K., Wallace, A., Bedford, M. R., Hawking, K. L., Rodrigues, I., Hilliar, M. & Choct, M. (2020). Carbohydrate Polymers, 230, 115645.
Xylan hydrolysis into xylo-oligosaccharides (XOS) was evaluated both in the gizzard and ileum of broiler chickens, and by a 2-step in vitro digestion assay that simulated the pH, temperature and time period of the gastric and small intestine (SI) phases. Twelve dietary treatments with varying soluble and insoluble xylan levels, either with or without supplemental xylanase, were fed to broiler chickens (n = 576) for the in situ analysis, and were exposed to the in vitro assay. Relatedness of the two methods was strong for determination of XOS production in all dietary treatments for X5, X4, X3, X2 and X1, respectively, in both the gastric (r = 0.980, 0.853, 0.894, 0.870 and 0.951) and small intestine phase (r = 0.957, 0.923, 0.940, 0.970, 0.969) (P < 0.05). Consequently, the in vitro assay was used to illustrated the diversity of XOS production across different batches of wheat and barley in the presence of xylanase.Hide Abstract
Production of xylooligosaccharides and monosaccharides from hydrogen peroxide-acetic acid-pretreated poplar by two-step enzymatic hydrolysis.
Hao, X., Wen, P., Wang, J., Wang, J., You, J. & Zhang, J. (2020). Bioresource Technology, 297, 122349.
The severe pretreatment of poplar makes xylan difficult to utilize efficiently. In this work, poplar was pretreated by hydrogen peroxide-acetic acid (HPAC) with H2SO4 as catalyst to remove lignin, and the solid residues were used to produce xylooligosaccharides (XOS) and monosaccharides by two-step xylanase and cellulase hydrolysis. The results indicated that higher H2SO4 concentrations in the HPAC pretreatment of poplar afforded stronger lignin removal ability. An increased XOS yield of 19.8% was obtained from 200 mM H2SO4-catalyzed poplar by xylanase and the XOS purity was high, with a very low xylose/XOS ratio of 0.14. Higher glucose (75.2%) and xylose (61.4%) yields were obtained from the HPAC-pretreated poplar using 50 mM H2SO4 as catalyst. Finally, 16.9 g XOS and 296.4 g glucose were produced from 1 kg poplar by xylanase and cellulase. This study provides a method for producing functional XOS and monosaccharides from poplar using a simple reduced-pollution strategy.Hide Abstract
Pilot-scale production of xylo-oligosaccharides and fermentable sugars from Miscanthus using steam explosion pretreatment.
Bhatia, R., Winters, A., Bryant, D. N., Bosch, M., Clifton-Brown, J., Leak, D. & Gallagher, J. (2020). Bioresource Technology, 296, 122285.
This study investigated pilot-scale production of xylo-oligosaccharides (XOS) and fermentable sugars from Miscanthus using steam explosion (SE) pretreatment. SE conditions (200°C; 15 bar; 10 min) led to XOS yields up to 52 % (w/w of initial xylan) in the hydrolysate. Liquid chromatography-mass spectrometry demonstrated that the solubilised XOS contained bound acetyl- and hydroxycinnamate residues, physicochemical properties known for high prebiotic effects and anti-oxidant activity in nutraceutical foods. Enzymatic hydrolysis of XOS-rich hydrolysate with commercial endo-xylanases resulted in xylobiose yields of 380 to 500 g/kg of initial xylan in the biomass after only 4 h, equivalent to ~74 to 90 % conversion of XOS into xylobiose. Fermentable glucose yields from enzymatic hydrolysis of solid residues were 8 to 9-fold higher than for untreated material. In view of an integrated biorefinery, we demonstrate the potential for efficient utilisation of Miscanthus for the production of renewable sources, including biochemicals and biofuels.Hide Abstract
Comparison of Japanese and Indian intestinal microbiota shows diet-dependent interaction between bacteria and fungi.
Pareek, S., Kurakawa, T., Das, B., Motooka, D., Nakaya, S., Rongsen-Chandola, T. et al. (2019). NPJ Biofilms and Microbiomes, 5(1), 1-13.
The bacterial species living in the gut mediate many aspects of biological processes such as nutrition and activation of adaptive immunity. In addition, commensal fungi residing in the intestine also influence host health. Although the interaction of bacterium and fungus has been shown, its precise mechanism during colonization of the human intestine remains largely unknown. Here, we show interaction between bacterial and fungal species for utilization of dietary components driving their efficient growth in the intestine. Next generation sequencing of fecal samples from Japanese and Indian adults revealed differential patterns of bacterial and fungal composition. In particular, Indians, who consume more plant polysaccharides than Japanese, harbored increased numbers of Prevotella and Candida. Candida spp. showed strong growth responses to the plant polysaccharide arabinoxylan in vitro. Furthermore, the culture supernatants of Candida spp. grown with arabinoxylan promoted rapid proliferation of Prevotella copri. Arabinose was identified as a potential growth-inducing factor in the Candida culture supernatants. Candida spp. exhibited a growth response to xylose, but not to arabinose, whereas P. copri proliferated in response to both xylose and arabinose. Candida spp., but not P. copri, colonized the intestine of germ-free mice. However, P. copri successfully colonized mouse intestine already harboring Candida. These findings demonstrate a proof of concept that fungal members of gut microbiota can facilitate a colonization of the intestine by their bacterial counterparts, potentially mediated by a dietary metabolite.Hide Abstract
Secondary lactic acid bacteria fermentation with wood-derived xylooligosaccharides as a tool to expedite sour beer production.
Dysvik, A., La Rosa, S. L., Buffetto, F., Liland, K. H., Myhrer, K. S., Rukke, E. O., Wicklund, T. & Westereng, B. (2019). Journal of Agricultural and Food Chemistry, 68(1), 301-314.
Xylooligosaccharides (XOS) from woody biomass were evaluated as a substrate for secondary lactic acid bacteria (LAB) fermentation in sour beer production. XOS were extracted from birch (Betula pubescens) and added to beer to promote the growth of Lactobacillus brevis BSO 464. Growth, pH, XOS degradation, and metabolic products were monitored throughout fermentations, and the final beer was evaluated sensorically. XOS were utilized, metabolic compounds were produced (1800 mg/L lactic acid), and pH was reduced from 4.1 to 3.6. Secondary fermentation changed sensory properties significantly, and the resulting sour beer was assessed as similar to a commercial reference in multiple attributes, including acidic taste. Overall, secondary LAB fermentation induced by wood-derived XOS provided a new approach to successfully produce sour beer with reduced fermentation time (from 1-3 years to 4 weeks). The presented results demonstrate how hemicellulosic biomass can be valorized for beverage production and to obtain sour beer with improved process control.Hide Abstract
Hydrophobic resin treatment of hydrothermal autohydrolysate for prebiotic applications.
Corbett, D. B., Hong, C., Venditti, R., Jameel, H. & Park, S. (2019). RSC Advances, 9(55), 31819-31827.
The production of a high-value xylooligosaccharide (XOS) prebiotic product from lignocellulosic autohydrolysate requires processing for the removal of non-carbohydrate components such as lignin and furfural. In this research, the nature of XOS dissolved in autohydrolysate is evaluated including the XOS degree of polymerization (DP) distribution and potential covalent association between XOS and lignin (LCC). The impact of these factors on the yield of XOS during treatment of Miscanthus autohydrolysate with hydrophobic resin is assessed. Over 30% of the XOS in autohydrolysate was found to be likely associated with lignin (“tied” XOS), all of which was removed during hydrophobic resin treatment along with over 90% of the dissolved lignin. However, loss of dissolved XOS during resin treatment was found to not be due solely to XOS association with lignin. Over 50% of the “free,” non-lignin-associated XOS was also removed by resin treatment. Interaction between “free” XOS and the hydrophobic resin was found to be highly dependent on DP with higher DP XOS being removed far more readily than low DP XOS. Over 80% of dissolved “free” XOS with a DP of six and above (X6+) was removed from autohydrolysate during treatment while only 17% of xylose (X1) was removed. Efforts to understand the interaction between the hydrophobic resin and XOS and to improve the recovery of XOS during hydrophobic resin treatment are presented.Hide Abstract
Sensitivity of the Bacillus subtilis Xyn A xylanase and its mutants to different xylanase inhibitors determines their activity profile and functionality during bread making.
Leys, S., De Bondt, Y., Schreurs, L. & Courtin, C. M. (2019). Journal of Agricultural and Food Chemistry, 67(40), 11198-11209.
The importance of inhibition sensitivity for xylanase functionality in bread making was investigated using mutants of the wild-type Bacillus subtilis xylanase (XBSTAXI), sensitive to Triticum aestivum xylanase inhibitor (TAXI). XBSNI, a mutant with reduced sensitivity to TAXI, and XBSTI, a mutant sensitive to all wheat endogenous proteinaceous inhibitors (TAXI, Xylanase Inhibiting Protein and Thaumatin-like Xylanase Inhibitor) were used. The higher inhibition sensitivity of XBSTAXI and XBSTI compared to XBSNI was associated with a respective 7- and 53-fold increase in enzyme dosage required for a maximal increase in bread loaf volume. XBSTI and XBSTAXI were only active during the mixing phase and the beginning of fermentation, while XBSNI was able to hydrolyze arabinoxylan until the end of fermentation. In spite of this difference in activity profile, no differences in loaf volume were observed for the different xylanases at optimal concentrations. Dough extensional viscosity analysis suggests that increased water availability as a result of xylanase activity favors starch-starch and starch-gluten interactions and drives the improvement in bread loaf volume.Hide Abstract
Xylooligosaccharides production from wheat middlings bioprocessed with Bacillus subtilis.
Reque, P. M., Pinilla, C. M. B., Gautério, G. V., Kalil, S. J., & Brandelli, A. (2019). Food Research International, 126, 108673.
Prebiotic compounds are substrates selectively metabolized by beneficial gut microbiota causing a health-promoting effect. Despite some prebiotic carbohydrates have been largely studied, xylooligosaccharides (XOS) are important prebiotics derived from arabinoxylans, which are polysaccharides found in cereals. This study aimed to investigate the production of xylanolytic enzymes and XOS during bioprocessing of wheat middlings, a product derived from wheat flour production, using a probiotic Bacillus subtilis. The composition of XOS and the enzymatic and prebiotic activities of resulting B. subtilis cultures were evaluated. The activity of xylanolytic enzymes continuously enhanced during the 72 h bacterial growth, where β-xylosidase presented the highest value (70.31 U/mL). XOS profile and concentration varied considerably between control and bioprocessed samples and among these at different times. Maximum prebiotic activity score was found for the 24 h and 72 h bioprocessed samples (1.73 and 1.61, respectively) using the commercial probiotic Lactobacillus acidophilus LA-5. Wheat middlings showed to be a promising substrate for production of prebiotics like XOS and B. subtilis FTC01 appears to be a good source of xylanolytic enzymes.Hide Abstract
Identification and characterization of a hyperthermophilic GH9 cellulase from the Arctic Mid-Ocean Ridge vent field.
Stepnov, A. A., Fredriksen, L., Steen, I. H., Stokke, R. & Eijsink, V. G. (2019). PloS One, 14(9), e0222216.
A novel GH9 cellulase (AMOR_GH9A) was discovered by sequence-based mining of a unique metagenomic dataset collected at the Jan Mayen hydrothermal vent field. AMOR_GH9A comprises a signal peptide, a catalytic domain and a CBM3 cellulose-binding module. AMOR_GH9A is an exceptionally stable enzyme with a temperature optimum around 100°C and an apparent melting temperature of 105°C. The novel cellulase retains 64% of its activity after 4 hours of incubation at 95°C. The closest characterized homolog of AMOR_GH9A is TfCel9A, a processive endocellulase from the model thermophilic bacterium Thermobifida fusca (64.2% sequence identity). Direct comparison of AMOR_GH9A and TfCel9A revealed that AMOR_GH9A possesses higher activity on soluble and amorphous substrates (phosphoric acid swollen cellulose, konjac glucomannan) and has an ability to hydrolyse xylan that is lacking in TfCel9A.Hide Abstract
Cloning of novel bacterial xylanases from lignocellulose-enriched compost metagenomic libraries.
Ellilä, S., Bromann, P., Nyyssönen, M., Itävaara, M., Koivula, A., Paulin, L. & Kruus, K. (2019). AMB Express, 9(1), 124.
Xylanases are in important class of industrial enzymes that are essential for the complete hydrolysis of lignocellulosic biomass into fermentable sugars. In the present study, we report the cloning of novel xylanases with interesting properties from compost metagenomics libraries. Controlled composting of lignocellulosic materials was used to enrich the microbial population in lignocellulolytic organisms. DNA extracted from the compost samples was used to construct metagenomics libraries, which were screened for xylanase activity. In total, 40 clones exhibiting xylanase activity were identified and the thermostability of the discovered xylanases was assayed directly from the library clones. Five genes, including one belonging to the more rare family GH8, were selected for subcloning and the enzymes were expressed in recombinant form in E. coli. Preliminary characterization of the metagenome-derived xylanases revealed interesting properties of the novel enzymes, such as high thermostability and specific activity, and differences in hydrolysis profiles. One enzyme was found to perform better than a standard Trichoderma reesei xylanase in the hydrolysis of lignocellulose at elevated temperatures.Hide Abstract