The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Aldo Todaro - One of the best experts on this subject based on the ideXlab platform.
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screening of durum wheat landraces triticum turgidum subsp durum for the malting suitability
Journal of Cereal Science, 2018Co-Authors: Vincenzo Alfeo, Barbara Jaskulagoiris, Ginfranco Venora, Emanuele Schimmenti, Guido Aerts, Aldo TodaroAbstract:Abstract Durum (T. turgidum subsp. durum) wheat production worldwide is substantially less than that of common wheat (Triticum aestivum) mainly due to the relatively limited end-users. In order to evaluate malting and brewing suitability, sixteen old durum wheat landraces were malted at micro scale. Results show malt quality parameters in the range 78.2–85.9% for the extract, 72.9–80.9% for the fermentability, 3–5 EBC units for the colour, 0.49–0.79% dm for water-extractable Arabinoxylans and 0.043–0.059% dm for the β-glucans. Regarding wort viscosity (1.53–1.92 mPa s), we found negative correlation with endo-1,4-β-D-xylanase, positive correlation with endo-β-glucanases and soluble proteins, while no correlations were found with Arabinoxylan and betaglucan wort content. These results showed that some durum wheats, such as Trentino, Martinella, Gioia, Inglesa, Francesa, Giustalisa and Bidi have suitable characteristics for malting and brewing. The improvement of the malting process is required for the other durum wheats.
Anne S Meyer - One of the best experts on this subject based on the ideXlab platform.
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a carbohydrate binding family 48 module enables feruloyl esterase action on polymeric Arabinoxylan
Journal of Biological Chemistry, 2019Co-Authors: Jesper Holck, Anne S Meyer, Folmer Fredslund, Marie Sofie Moller, Jesper Brask, Kristian B R M Krogh, Lene Lange, Ditte Hededam Welner, Birte Svensson, Casper WilkensAbstract:: Feruloyl esterases (EC 3.1.1.73), belonging to carbohydrate esterase family 1 (CE1), hydrolyze ester bonds between ferulic acid (FA) and arabinose moieties in Arabinoxylans. Recently, some CE1 enzymes identified in metagenomics studies have been predicted to contain a family 48 carbohydrate-binding module (CBM48), a CBM family associated with starch binding. Two of these CE1s, wastewater treatment sludge (wts) Fae1A and wtsFae1B isolated from wastewater treatment surplus sludge, have a cognate CBM48 domain and are feruloyl esterases, and wtsFae1A binds Arabinoxylan. Here, we show that wtsFae1B also binds to Arabinoxylan and that neither binds starch. Surface plasmon resonance analysis revealed that wtsFae1B's Kd for xylohexaose is 14.8 μm and that it does not bind to starch mimics, β-cyclodextrin, or maltohexaose. Interestingly, in the absence of CBM48 domains, the CE1 regions from wtsFae1A and wtsFae1B did not bind Arabinoxylan and were also unable to catalyze FA release from Arabinoxylan. Pretreatment with a β-d-1,4-xylanase did enable CE1 domain-mediated FA release from Arabinoxylan in the absence of CBM48, indicating that CBM48 is essential for the CE1 activity on the polysaccharide. Crystal structures of wtsFae1A (at 1.63 A resolution) and wtsFae1B (1.98 A) revealed that both are folded proteins comprising structurally-conserved hydrogen bonds that lock the CBM48 position relative to that of the CE1 domain. wtsFae1A docking indicated that both enzymes accommodate the Arabinoxylan backbone in a cleft at the CE1-CBM48 domain interface. Binding at this cleft appears to enable CE1 activities on polymeric Arabinoxylan, illustrating an unexpected and crucial role of CBM48 domains for accommodating Arabinoxylan.
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characterization of solubilized arabinoxylo oligosaccharides by maldi tof ms analysis to unravel and direct enzyme catalyzed hydrolysis of insoluble wheat Arabinoxylan
Enzyme and Microbial Technology, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Anne S MeyerAbstract:Abstract Hydrolysis of Arabinoxylan is an important prerequisite for valorization of wheat endosperm materials, but the water insoluble Arabinoxylan fraction of wheat endosperm cell walls has proven difficult to hydrolyze enzymatically. In this study, enzymatic hydrolysis of purified, water insoluble wheat Arabinoxylan was examined and improved by combining detailed substrate analysis with analyses of product monosaccharides and oligosaccharides after treatments with rationally composed enzyme mixtures. Treatment of purified, water insoluble wheat Arabinoxylan (substrate concentration 1.0%, w/w) for 48 h at pH 5, 50 °C with a combination of β-xylosidase from Trichoderma reesei and a hemicellulolytic fungal enzyme preparation from Humicola insolens, Ultraflo L, liberated 1.6 mg ferulic acid, 24 mg acetic acid, 51 mg arabinose, 167 mg xylose, and furthermore, solubilized 244 mg oligosaccharides per gram substrate dry matter. This yield was equivalent to solubilization of 45% by weight of the insoluble wheat Arabinoxylan. Analysis of the solubilized oligomers by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) analysis revealed presence of different feruloylated and acetylated pentose oligomers. The data thus signified the presence of acetyl groups in wheat Arabinoxylan. Addition of acetyl xylan esterase from Aspergillus aculeatus on top of the Ultraflo L and β-xylosidase addition did however not facilitate additional degradation of the insoluble wheat Arabinoxylan, whereas, addition of feruloyl esterase obtained from Aspergillus niger on top of the β-xylosidase and Ultraflo L blend solubilized an additional 1.9% (w/w) dry matter from the substrate and significantly changed the MALDI-TOF MS profile of the solubilized oligomers which became significantly less feruloylated after this enzyme treatment.
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synergistic enzyme mechanisms and effects of sequential enzyme additions on degradation of water insoluble wheat Arabinoxylan
Enzyme and Microbial Technology, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Anne S MeyerAbstract:Abstract Generation of a fermentable hydrolysate from Arabinoxylan is a first prerequisite in the utilization of wheat hemicellulose in the biofuel industry. This study examined the efficacy of four hemicellulolytic microbial enzyme preparations and one xylanase preparation in catalyzing degradation of purified water soluble and water insoluble wheat Arabinoxylan—with particular emphasis on the catalytic degradation of water insoluble Arabinoxylan. The effects of individual enzyme treatments were compared by assessing yields of arabinose, xylose, and xylobiose obtained under different reaction conditions of pH and temperature in response surface designs. In general, the monosaccharide yields obtained were lower on the water insoluble wheat Arabinoxylan than on the water soluble. On both substrates, the Ultraflo L preparation from Humicola insolens was best in catalyzing arabinose and xylobiose release, while the Celluclast 1.5 L preparation from Trichoderma reesei was superior to all the other enzyme preparations in catalyzing xylose release. Treatments with 50:50 combinations of the enzyme preparations only resulted in a pronounced synergistic xylose release with a mixture of Ultraflo L:Celluclast 1.5 L. Examination of the progress of the substrate degradation indicated that the synergism on the insoluble Arabinoxylan resembled what we have previously observed on soluble Arabinoxylan, i.e. that the effect was a result of positive interaction in arabinose release and xylan depolymerization between the α- l -arabinofuranosidase (EC 3.2.1.55) and endo-1,4-β-xylanase (EC 3.2.1.8) activities present in Ultraflo L, and between the β-xylosidase (EC 3.2.1.37) activity present in the Celluclast 1.5 L. The results of treatments with combinations of Ultraflo L and purified T. reesei β-xylosidase – with both simultaneous and sequential addition, and with and without contemporary pH adjustments to optimize individual enzyme activities – strongly corroborated this conclusion.
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Enzymatic Hydrolysis of Wheat Arabinoxylan by a Recombinant "Minimal" Enzyme Cocktail Containing beta-Xylosidase and Novel endo-1,4-beta-Xylanase and alpha-L-Arabinofuranosidase Activities
Biotechnology progress, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Christel Thea Jorgensen, Anne S MeyerAbstract:This study describes the identification of the key enzyme activities required in a "minimal" enzyme cocktail able to catalyze hydrolysis of water-soluble and water-insoluble wheat Arabinoxylan and whole vinasse, a fermentation effluent resulting from industrial ethanol manufacture from wheat. The optimal arabinose-releasing and xylan-depolymerizing enzyme activities were identified from data obtained when selected, recombinant enzymes were systematically supplemented to the different Arabinoxylan substrates in mixtures; this examination revealed three novel alpha-l-arabinofuranosidase activities: (i) one GH51 enzyme from Meripilus giganteus and (ii) one GH51 enzyme from Humicola insolens, both able to catalyze arabinose release from singly substituted xylose; and (iii) one GH43 enzyme from H. insolens able to catalyze the release of arabinose from doubly substituted xylose. Treatment of water-soluble and water-insoluble wheat Arabinoxylan with an enzyme cocktail containing a 20%:20%:20%:40% mixture and a 25%:25%:25%:25% mixture, respectively, of the GH43 alpha-l-arabinofuranosidase from H. insolens (Abf II), the GH51 alpha-l-arabinofuranosidase from M. giganteus (Abf III), a GH10 endo-1,4-beta-xylanase from H. insolens (Xyl III), and a GH3 beta-xylosidase from Trichoderma reesei (beta-xyl) released 322 mg of arabinose and 512 mg of xylose per gram of water-soluble wheat Arabinoxylan dry matter and 150 mg of arabinose and 266 mg of xylose per gram of water-insoluble wheat Arabinoxylan dry matter after 24 h at pH 5, 50 degrees C. A 10%:40%:50% mixture of Abf II, Abf III, and beta-xyl released 56 mg of arabinose and 91 mg of xylose per gram of vinasse dry matter after 24 h at pH 5, 50 degrees C. The optimal dosages of the "minimal" enzyme cocktails were determined to be 0.4, 0.3, and 0.2 g enzyme protein per kilogram of substrate dry matter for the water-soluble wheat Arabinoxylan, the water-insoluble wheat Arabinoxylan, and the vinasse, respectively. These enzyme protein dosage levels were approximately 14, approximately 18, and approximately 27 times lower than the dosages used previously, when the same wheat Arabinoxylan substrates were hydrolyzed with a combination of Ultraflo L and Celluclast 1.5 L, two commercially available enzyme preparations produced by H. insolens and T. reesei.
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enzymatic hydrolysis of wheat Arabinoxylan by a recombinant minimal enzyme cocktail containing β xylosidase and novel endo 1 4 β xylanase and α l arabinofuranosidase activities
Biotechnology Progress, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Christel Thea Jorgensen, Anne S MeyerAbstract:This study describes the identification of the key enzyme activities required in a "minimal" enzyme cocktail able to catalyze hydrolysis of water-soluble and water-insoluble wheat Arabinoxylan and whole vinasse, a fermentation effluent resulting from industrial ethanol manufacture from wheat. The optimal arabinose-releasing and xylan-depolymerizing enzyme activities were identified from data obtained when selected, recombinant enzymes were systematically supplemented to the different Arabinoxylan substrates in mixtures; this examination revealed three novel alpha-l-arabinofuranosidase activities: (i) one GH51 enzyme from Meripilus giganteus and (ii) one GH51 enzyme from Humicola insolens, both able to catalyze arabinose release from singly substituted xylose; and (iii) one GH43 enzyme from H. insolens able to catalyze the release of arabinose from doubly substituted xylose. Treatment of water-soluble and water-insoluble wheat Arabinoxylan with an enzyme cocktail containing a 20%:20%:20%:40% mixture and a 25%:25%:25%:25% mixture, respectively, of the GH43 alpha-l-arabinofuranosidase from H. insolens (Abf II), the GH51 alpha-l-arabinofuranosidase from M. giganteus (Abf III), a GH10 endo-1,4-beta-xylanase from H. insolens (Xyl III), and a GH3 beta-xylosidase from Trichoderma reesei (beta-xyl) released 322 mg of arabinose and 512 mg of xylose per gram of water-soluble wheat Arabinoxylan dry matter and 150 mg of arabinose and 266 mg of xylose per gram of water-insoluble wheat Arabinoxylan dry matter after 24 h at pH 5, 50 degrees C. A 10%:40%:50% mixture of Abf II, Abf III, and beta-xyl released 56 mg of arabinose and 91 mg of xylose per gram of vinasse dry matter after 24 h at pH 5, 50 degrees C. The optimal dosages of the "minimal" enzyme cocktails were determined to be 0.4, 0.3, and 0.2 g enzyme protein per kilogram of substrate dry matter for the water-soluble wheat Arabinoxylan, the water-insoluble wheat Arabinoxylan, and the vinasse, respectively. These enzyme protein dosage levels were approximately 14, approximately 18, and approximately 27 times lower than the dosages used previously, when the same wheat Arabinoxylan substrates were hydrolyzed with a combination of Ultraflo L and Celluclast 1.5 L, two commercially available enzyme preparations produced by H. insolens and T. reesei.
Jan A. Delcour - One of the best experts on this subject based on the ideXlab platform.
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prebiotic and other health related effects of cereal derived Arabinoxylans Arabinoxylan oligosaccharides and xylooligosaccharides
Critical Reviews in Food Science and Nutrition, 2011Co-Authors: Willem F Broekaert, Tom Van De Wiele, Willy Verstraete, Christophe M. Courtin, Kristin Verbeke, Jan A. DelcourAbstract:Arabinoxylans (AX) from cereals are cell wall components that constitute an important part of the dietary fiber intake in humans. Enzymatic hydrolysis of AX yields Arabinoxylan-oligosaccharides (AXOS), consisting of arabinoxylooligosaccharides and xylooligosaccharides (XOS). This reaction takes place in the production of AXOS and of cereal-derived food products such as bread and beer, as well as in the colon upon ingestion of AX. This review mainly focuses on the available evidence that AXOS and XOS exert prebiotic effects in the colon of humans and animals through selective stimulation of beneficial intestinal microbiota. In addition, in vitro experiments and in vivo intervention studies on animals or humans are discussed that have investigated potential health-related effects resulting from the dietary intake of AX, AXOS, or XOS.
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tolerance of Arabinoxylan oligosaccharides and their prebiotic activity in healthy subjects a randomised placebo controlled cross over study
British Journal of Nutrition, 2010Co-Authors: Lieselotte Cloetens, Jan A. Delcour, Christophe M. Courtin, Willem F Broekaert, Yasmine Delaedt, Frans Ollevier, Paul Rutgeerts, Kristin VerbekeAbstract:The tolerance and prebiotic effect following oral intake by healthy human subjects of Arabinoxylan-oligosaccharides (AXOS), produced by partial enzymic hydrolysis of the wheat fibre arabinoxlyan, were studied. A total of twenty healthy subjects participated in the present randomised, placebo-controlled cross-over study. They consumed 10 g AXOS or placebo per d each for 3 weeks with a 4-week wash-out period in between. Before and immediately after each intake period, blood samples were taken to measure haematological and clinical chemistry parameters and the subjects completed a questionnaire about gastrointestinal symptoms. Additionally, urine was collected over 48 h for analysis of p-cresol and phenol content by GC ‐ MS, and faeces were collected over 72 h for analysis of microbiota using real-time PCR. Of the subjects, ten also performed a urine and faeces collection 2 weeks after the start of intake (during intervention). A limited number of tested blood parameters were influenced in a statistically significantly way by either AXOS or placebo intake, but these changes remained within the normal range. Blood lipids remained unchanged. AXOS had no statistically significant effect on the range of gastrointestinal symptoms, except for a mild increase in flatulence. Urinary p-cresol excretion, an indicator of protein fermentation, was significantly decreased after 2 weeks of AXOS intake. The levels of bifidobacteria were significantly increased after 2 and 3 weeks of AXOS intake as well as after 3 weeks of placebo. However, the effect of AXOS on bifidobacteria was more pronounced than that of placebo. In conclusion, AXOS are a well-tolerated prebiotic at the dose of 10 g/d. AXOS intake increases faecal bifidobacteria and reduces urinary p-cresol excretion. Arabinoxylan-oligosaccharides: Prebiotics: Protein fermentation: Tolerance
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Effects of genotype, harvest year and genotype-by-harvest year interactions on Arabinoxylan, endoxylanase activity and endoxylanase inhibitor levels in wheat kernels
Journal of Cereal Science, 2008Co-Authors: Emmie Dornez, Kurt Gebruers, Jan A. Delcour, Iris J. Joye, Bart De Ketelaere, Jonathan Lenartz, Carine Massaux, Bernard Bodson, Christophe M. CourtinAbstract:Abstract The effects of genotype, harvest year and their interaction on the levels of Arabinoxylans (AX), endoxylanases and endoxylanase inhibitors in wheat were studied using 14 varieties grown in three successive growing periods with diverse climatological conditions. Relations with more commonly evaluated wheat characteristics such as yield, thousand kernel weight, specific weight, protein level, Hagberg falling number (HFN) and α -amylase activity level were examined. Water extractable Arabinoxylan (WE-AX) levels in wheat varied much more than total Arabinoxylan (TOT-AX) levels. This variability was mainly genetically determined, but harvest year also had an important effect. Total endoxylanase activity levels varied more than a factor of 20 between the different wheat samples. Endogenous endoxylanases typically accounted for only 10–15% of this activity, while wheat-associated microbial endoxylanases accounted for the remaining 85–90%. However, when preharvest sprouting occurred, the contribution of endogenous endoxylanases could sometimes amount to over 40% of this total activity. Endogenous endoxylanase activity levels were mainly determined by the interaction of genotype and harvest year, while wheat-associated microbial endoxylanase activity levels were predominantly determined by genotype alone. Endogenous and microbial endoxylanase activity levels were strongly correlated, suggesting that wheat varieties which are susceptible to preharvest sprouting are often also susceptible to microbial contamination. The TAXI and XIP-type endoxylanase inhibitor levels varied by a factor of 8 and 1.8, respectively. They were mainly determined by genotype and were rather similar in the different growing periods.
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microbial metabolism and prebiotic potency of Arabinoxylan oligosaccharides in the human intestine
Trends in Food Science and Technology, 2007Co-Authors: Charlotte Grootaert, Willy Verstraete, Jan A. Delcour, Christophe M. Courtin, Willem F Broekaert, Tom Van De WieleAbstract:Arabinoxylans (AX) are the main non-starch polysaccharides found in many cereal grains and are part of dietary fibre. They consist of β-(1,4)-linked d-xylopyranosyl residues to which arabinofuranosyl moieties are attached. They are degraded in the colon by specific intestinal bacteria possessing AX-degrading enzymes. Although some health effects of AX are documented, the effects of their hydrolysis products, the Arabinoxylan oligosaccharides (AXOS), are less studied. Many oligosaccharides exert prebiotic activities and there are indications that xylo-oligosaccharides consisting of β-(1,4)-linked d-xylopyranosyl residues show strong bifidogenic effects. Therefore, the in-depth study of the prebiotic potential of AXOS and the intestinal microbiota involved in their transformation processes is warranted.
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Arabinoxylans and endoxylanases in wheat flour bread making
Journal of Cereal Science, 2002Co-Authors: Christophe M. Courtin, Jan A. DelcourAbstract:For the past 50 years the function of Arabinoxylans in bread-making has been the subject of much debate and controversy. In the last decade, these molecules have been put in the spotlight again inter alia because of the increasing use of endoxylanases in European wheat and rye flour bread-making processes. This renewed interest has led to considerable advances in the understanding of both Arabinoxylan and endoxylanase functionalities in bread-making. We here present a survey of the relevant work. Knowledge of both the substrate (Arabinoxylan) and the enzyme (endoxylanase), as well as of recently discovered endoxylanase inhibitors, is summarised. Facts on Arabinoxylans and endoxylanases in wheat flour bread-making are presented and integrated in an up-to-date view on their functionality in bread-making.
Hanne Risbjerg Sorensen - One of the best experts on this subject based on the ideXlab platform.
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characterization of solubilized arabinoxylo oligosaccharides by maldi tof ms analysis to unravel and direct enzyme catalyzed hydrolysis of insoluble wheat Arabinoxylan
Enzyme and Microbial Technology, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Anne S MeyerAbstract:Abstract Hydrolysis of Arabinoxylan is an important prerequisite for valorization of wheat endosperm materials, but the water insoluble Arabinoxylan fraction of wheat endosperm cell walls has proven difficult to hydrolyze enzymatically. In this study, enzymatic hydrolysis of purified, water insoluble wheat Arabinoxylan was examined and improved by combining detailed substrate analysis with analyses of product monosaccharides and oligosaccharides after treatments with rationally composed enzyme mixtures. Treatment of purified, water insoluble wheat Arabinoxylan (substrate concentration 1.0%, w/w) for 48 h at pH 5, 50 °C with a combination of β-xylosidase from Trichoderma reesei and a hemicellulolytic fungal enzyme preparation from Humicola insolens, Ultraflo L, liberated 1.6 mg ferulic acid, 24 mg acetic acid, 51 mg arabinose, 167 mg xylose, and furthermore, solubilized 244 mg oligosaccharides per gram substrate dry matter. This yield was equivalent to solubilization of 45% by weight of the insoluble wheat Arabinoxylan. Analysis of the solubilized oligomers by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) analysis revealed presence of different feruloylated and acetylated pentose oligomers. The data thus signified the presence of acetyl groups in wheat Arabinoxylan. Addition of acetyl xylan esterase from Aspergillus aculeatus on top of the Ultraflo L and β-xylosidase addition did however not facilitate additional degradation of the insoluble wheat Arabinoxylan, whereas, addition of feruloyl esterase obtained from Aspergillus niger on top of the β-xylosidase and Ultraflo L blend solubilized an additional 1.9% (w/w) dry matter from the substrate and significantly changed the MALDI-TOF MS profile of the solubilized oligomers which became significantly less feruloylated after this enzyme treatment.
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synergistic enzyme mechanisms and effects of sequential enzyme additions on degradation of water insoluble wheat Arabinoxylan
Enzyme and Microbial Technology, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Anne S MeyerAbstract:Abstract Generation of a fermentable hydrolysate from Arabinoxylan is a first prerequisite in the utilization of wheat hemicellulose in the biofuel industry. This study examined the efficacy of four hemicellulolytic microbial enzyme preparations and one xylanase preparation in catalyzing degradation of purified water soluble and water insoluble wheat Arabinoxylan—with particular emphasis on the catalytic degradation of water insoluble Arabinoxylan. The effects of individual enzyme treatments were compared by assessing yields of arabinose, xylose, and xylobiose obtained under different reaction conditions of pH and temperature in response surface designs. In general, the monosaccharide yields obtained were lower on the water insoluble wheat Arabinoxylan than on the water soluble. On both substrates, the Ultraflo L preparation from Humicola insolens was best in catalyzing arabinose and xylobiose release, while the Celluclast 1.5 L preparation from Trichoderma reesei was superior to all the other enzyme preparations in catalyzing xylose release. Treatments with 50:50 combinations of the enzyme preparations only resulted in a pronounced synergistic xylose release with a mixture of Ultraflo L:Celluclast 1.5 L. Examination of the progress of the substrate degradation indicated that the synergism on the insoluble Arabinoxylan resembled what we have previously observed on soluble Arabinoxylan, i.e. that the effect was a result of positive interaction in arabinose release and xylan depolymerization between the α- l -arabinofuranosidase (EC 3.2.1.55) and endo-1,4-β-xylanase (EC 3.2.1.8) activities present in Ultraflo L, and between the β-xylosidase (EC 3.2.1.37) activity present in the Celluclast 1.5 L. The results of treatments with combinations of Ultraflo L and purified T. reesei β-xylosidase – with both simultaneous and sequential addition, and with and without contemporary pH adjustments to optimize individual enzyme activities – strongly corroborated this conclusion.
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Enzymatic Hydrolysis of Wheat Arabinoxylan by a Recombinant "Minimal" Enzyme Cocktail Containing beta-Xylosidase and Novel endo-1,4-beta-Xylanase and alpha-L-Arabinofuranosidase Activities
Biotechnology progress, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Christel Thea Jorgensen, Anne S MeyerAbstract:This study describes the identification of the key enzyme activities required in a "minimal" enzyme cocktail able to catalyze hydrolysis of water-soluble and water-insoluble wheat Arabinoxylan and whole vinasse, a fermentation effluent resulting from industrial ethanol manufacture from wheat. The optimal arabinose-releasing and xylan-depolymerizing enzyme activities were identified from data obtained when selected, recombinant enzymes were systematically supplemented to the different Arabinoxylan substrates in mixtures; this examination revealed three novel alpha-l-arabinofuranosidase activities: (i) one GH51 enzyme from Meripilus giganteus and (ii) one GH51 enzyme from Humicola insolens, both able to catalyze arabinose release from singly substituted xylose; and (iii) one GH43 enzyme from H. insolens able to catalyze the release of arabinose from doubly substituted xylose. Treatment of water-soluble and water-insoluble wheat Arabinoxylan with an enzyme cocktail containing a 20%:20%:20%:40% mixture and a 25%:25%:25%:25% mixture, respectively, of the GH43 alpha-l-arabinofuranosidase from H. insolens (Abf II), the GH51 alpha-l-arabinofuranosidase from M. giganteus (Abf III), a GH10 endo-1,4-beta-xylanase from H. insolens (Xyl III), and a GH3 beta-xylosidase from Trichoderma reesei (beta-xyl) released 322 mg of arabinose and 512 mg of xylose per gram of water-soluble wheat Arabinoxylan dry matter and 150 mg of arabinose and 266 mg of xylose per gram of water-insoluble wheat Arabinoxylan dry matter after 24 h at pH 5, 50 degrees C. A 10%:40%:50% mixture of Abf II, Abf III, and beta-xyl released 56 mg of arabinose and 91 mg of xylose per gram of vinasse dry matter after 24 h at pH 5, 50 degrees C. The optimal dosages of the "minimal" enzyme cocktails were determined to be 0.4, 0.3, and 0.2 g enzyme protein per kilogram of substrate dry matter for the water-soluble wheat Arabinoxylan, the water-insoluble wheat Arabinoxylan, and the vinasse, respectively. These enzyme protein dosage levels were approximately 14, approximately 18, and approximately 27 times lower than the dosages used previously, when the same wheat Arabinoxylan substrates were hydrolyzed with a combination of Ultraflo L and Celluclast 1.5 L, two commercially available enzyme preparations produced by H. insolens and T. reesei.
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enzymatic hydrolysis of wheat Arabinoxylan by a recombinant minimal enzyme cocktail containing β xylosidase and novel endo 1 4 β xylanase and α l arabinofuranosidase activities
Biotechnology Progress, 2007Co-Authors: Hanne Risbjerg Sorensen, Sven Pedersen, Christel Thea Jorgensen, Anne S MeyerAbstract:This study describes the identification of the key enzyme activities required in a "minimal" enzyme cocktail able to catalyze hydrolysis of water-soluble and water-insoluble wheat Arabinoxylan and whole vinasse, a fermentation effluent resulting from industrial ethanol manufacture from wheat. The optimal arabinose-releasing and xylan-depolymerizing enzyme activities were identified from data obtained when selected, recombinant enzymes were systematically supplemented to the different Arabinoxylan substrates in mixtures; this examination revealed three novel alpha-l-arabinofuranosidase activities: (i) one GH51 enzyme from Meripilus giganteus and (ii) one GH51 enzyme from Humicola insolens, both able to catalyze arabinose release from singly substituted xylose; and (iii) one GH43 enzyme from H. insolens able to catalyze the release of arabinose from doubly substituted xylose. Treatment of water-soluble and water-insoluble wheat Arabinoxylan with an enzyme cocktail containing a 20%:20%:20%:40% mixture and a 25%:25%:25%:25% mixture, respectively, of the GH43 alpha-l-arabinofuranosidase from H. insolens (Abf II), the GH51 alpha-l-arabinofuranosidase from M. giganteus (Abf III), a GH10 endo-1,4-beta-xylanase from H. insolens (Xyl III), and a GH3 beta-xylosidase from Trichoderma reesei (beta-xyl) released 322 mg of arabinose and 512 mg of xylose per gram of water-soluble wheat Arabinoxylan dry matter and 150 mg of arabinose and 266 mg of xylose per gram of water-insoluble wheat Arabinoxylan dry matter after 24 h at pH 5, 50 degrees C. A 10%:40%:50% mixture of Abf II, Abf III, and beta-xyl released 56 mg of arabinose and 91 mg of xylose per gram of vinasse dry matter after 24 h at pH 5, 50 degrees C. The optimal dosages of the "minimal" enzyme cocktails were determined to be 0.4, 0.3, and 0.2 g enzyme protein per kilogram of substrate dry matter for the water-soluble wheat Arabinoxylan, the water-insoluble wheat Arabinoxylan, and the vinasse, respectively. These enzyme protein dosage levels were approximately 14, approximately 18, and approximately 27 times lower than the dosages used previously, when the same wheat Arabinoxylan substrates were hydrolyzed with a combination of Ultraflo L and Celluclast 1.5 L, two commercially available enzyme preparations produced by H. insolens and T. reesei.
Christophe M. Courtin - One of the best experts on this subject based on the ideXlab platform.
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prebiotic and other health related effects of cereal derived Arabinoxylans Arabinoxylan oligosaccharides and xylooligosaccharides
Critical Reviews in Food Science and Nutrition, 2011Co-Authors: Willem F Broekaert, Tom Van De Wiele, Willy Verstraete, Christophe M. Courtin, Kristin Verbeke, Jan A. DelcourAbstract:Arabinoxylans (AX) from cereals are cell wall components that constitute an important part of the dietary fiber intake in humans. Enzymatic hydrolysis of AX yields Arabinoxylan-oligosaccharides (AXOS), consisting of arabinoxylooligosaccharides and xylooligosaccharides (XOS). This reaction takes place in the production of AXOS and of cereal-derived food products such as bread and beer, as well as in the colon upon ingestion of AX. This review mainly focuses on the available evidence that AXOS and XOS exert prebiotic effects in the colon of humans and animals through selective stimulation of beneficial intestinal microbiota. In addition, in vitro experiments and in vivo intervention studies on animals or humans are discussed that have investigated potential health-related effects resulting from the dietary intake of AX, AXOS, or XOS.
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tolerance of Arabinoxylan oligosaccharides and their prebiotic activity in healthy subjects a randomised placebo controlled cross over study
British Journal of Nutrition, 2010Co-Authors: Lieselotte Cloetens, Jan A. Delcour, Christophe M. Courtin, Willem F Broekaert, Yasmine Delaedt, Frans Ollevier, Paul Rutgeerts, Kristin VerbekeAbstract:The tolerance and prebiotic effect following oral intake by healthy human subjects of Arabinoxylan-oligosaccharides (AXOS), produced by partial enzymic hydrolysis of the wheat fibre arabinoxlyan, were studied. A total of twenty healthy subjects participated in the present randomised, placebo-controlled cross-over study. They consumed 10 g AXOS or placebo per d each for 3 weeks with a 4-week wash-out period in between. Before and immediately after each intake period, blood samples were taken to measure haematological and clinical chemistry parameters and the subjects completed a questionnaire about gastrointestinal symptoms. Additionally, urine was collected over 48 h for analysis of p-cresol and phenol content by GC ‐ MS, and faeces were collected over 72 h for analysis of microbiota using real-time PCR. Of the subjects, ten also performed a urine and faeces collection 2 weeks after the start of intake (during intervention). A limited number of tested blood parameters were influenced in a statistically significantly way by either AXOS or placebo intake, but these changes remained within the normal range. Blood lipids remained unchanged. AXOS had no statistically significant effect on the range of gastrointestinal symptoms, except for a mild increase in flatulence. Urinary p-cresol excretion, an indicator of protein fermentation, was significantly decreased after 2 weeks of AXOS intake. The levels of bifidobacteria were significantly increased after 2 and 3 weeks of AXOS intake as well as after 3 weeks of placebo. However, the effect of AXOS on bifidobacteria was more pronounced than that of placebo. In conclusion, AXOS are a well-tolerated prebiotic at the dose of 10 g/d. AXOS intake increases faecal bifidobacteria and reduces urinary p-cresol excretion. Arabinoxylan-oligosaccharides: Prebiotics: Protein fermentation: Tolerance
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Effects of genotype, harvest year and genotype-by-harvest year interactions on Arabinoxylan, endoxylanase activity and endoxylanase inhibitor levels in wheat kernels
Journal of Cereal Science, 2008Co-Authors: Emmie Dornez, Kurt Gebruers, Jan A. Delcour, Iris J. Joye, Bart De Ketelaere, Jonathan Lenartz, Carine Massaux, Bernard Bodson, Christophe M. CourtinAbstract:Abstract The effects of genotype, harvest year and their interaction on the levels of Arabinoxylans (AX), endoxylanases and endoxylanase inhibitors in wheat were studied using 14 varieties grown in three successive growing periods with diverse climatological conditions. Relations with more commonly evaluated wheat characteristics such as yield, thousand kernel weight, specific weight, protein level, Hagberg falling number (HFN) and α -amylase activity level were examined. Water extractable Arabinoxylan (WE-AX) levels in wheat varied much more than total Arabinoxylan (TOT-AX) levels. This variability was mainly genetically determined, but harvest year also had an important effect. Total endoxylanase activity levels varied more than a factor of 20 between the different wheat samples. Endogenous endoxylanases typically accounted for only 10–15% of this activity, while wheat-associated microbial endoxylanases accounted for the remaining 85–90%. However, when preharvest sprouting occurred, the contribution of endogenous endoxylanases could sometimes amount to over 40% of this total activity. Endogenous endoxylanase activity levels were mainly determined by the interaction of genotype and harvest year, while wheat-associated microbial endoxylanase activity levels were predominantly determined by genotype alone. Endogenous and microbial endoxylanase activity levels were strongly correlated, suggesting that wheat varieties which are susceptible to preharvest sprouting are often also susceptible to microbial contamination. The TAXI and XIP-type endoxylanase inhibitor levels varied by a factor of 8 and 1.8, respectively. They were mainly determined by genotype and were rather similar in the different growing periods.
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microbial metabolism and prebiotic potency of Arabinoxylan oligosaccharides in the human intestine
Trends in Food Science and Technology, 2007Co-Authors: Charlotte Grootaert, Willy Verstraete, Jan A. Delcour, Christophe M. Courtin, Willem F Broekaert, Tom Van De WieleAbstract:Arabinoxylans (AX) are the main non-starch polysaccharides found in many cereal grains and are part of dietary fibre. They consist of β-(1,4)-linked d-xylopyranosyl residues to which arabinofuranosyl moieties are attached. They are degraded in the colon by specific intestinal bacteria possessing AX-degrading enzymes. Although some health effects of AX are documented, the effects of their hydrolysis products, the Arabinoxylan oligosaccharides (AXOS), are less studied. Many oligosaccharides exert prebiotic activities and there are indications that xylo-oligosaccharides consisting of β-(1,4)-linked d-xylopyranosyl residues show strong bifidogenic effects. Therefore, the in-depth study of the prebiotic potential of AXOS and the intestinal microbiota involved in their transformation processes is warranted.
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Arabinoxylans and endoxylanases in wheat flour bread making
Journal of Cereal Science, 2002Co-Authors: Christophe M. Courtin, Jan A. DelcourAbstract:For the past 50 years the function of Arabinoxylans in bread-making has been the subject of much debate and controversy. In the last decade, these molecules have been put in the spotlight again inter alia because of the increasing use of endoxylanases in European wheat and rye flour bread-making processes. This renewed interest has led to considerable advances in the understanding of both Arabinoxylan and endoxylanase functionalities in bread-making. We here present a survey of the relevant work. Knowledge of both the substrate (Arabinoxylan) and the enzyme (endoxylanase), as well as of recently discovered endoxylanase inhibitors, is summarised. Facts on Arabinoxylans and endoxylanases in wheat flour bread-making are presented and integrated in an up-to-date view on their functionality in bread-making.