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1
Kocabas, Aytac. "Co-production Of Xylanase And Itaconic Acid By Aspergillus Terreus Nrrl 1960 On Agricultural Biomass And Biochemical Characterization Of Xylanase". Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12612067/index.pdf.
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Production of xylanase and itaconic acid (IA) from Aspergillus terreus NRRL 1960 from agricultural residues was investigated in this study. Two different media were tested and the medium having itaconic acid inducing capacity was chosen for further studies due to its high xylanase and IA production capacity. The best xylan concentration was found as 2% (w/v). Addition of commercial xylanase to production culture resulted in higher initial simple sugar concentration which increased IA production slightly but decreased xylanase production.
Among tested agricultural residuescorn cob, cotton stalk and sunflower stalk, the highest xylanase production was obtained on corn cob. Increasing the corn cob concentration and applying wet heat pretreatment increased the xylanase production level. In a two-step fermentation process, 70000 IU/L xylanase production was achieved in a medium containing 7% wet heat treated corn cob followed by 17 g/L IA production in a medium containing 10% glucose. Molecular weight and isoelectric point of xylanase were found as 19 kDa and pH 9.0, respectively. The enzyme was optimally active at 50°
C and pH 6.5-7.0. Kinetic experiments at 50°
C and pH 7.0 resulted in apparent Km and Vmax values of 2.5±
0.05 mg xylan/mL and 50.2±
0.4 IU/µ
g protein, respectively. The major products of birchwood xylan hydrolysis were determined by thin layer chromatography as xylobiose and xylotriose. These findings indicate that the enzyme could be advantageous for use in different industrial applications due to its low molecular weight and its potential use for xylooligosaccharide production.
2
Hilly, Lynette. "Bacillus species as potential probiotics for poultry: Role of xylanase production". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/235927/1/Lynette%2BHilly%2BThesis%281%29.pdf.
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Probiotics contain bacteria that are beneficial to the gut and have demonstrated to improve the health status of production animals including improved growth performance, protection against intestinal pathogens and enhanced immunity. The mechanisms of how these effects are achieved remains poorly understood. Thus, the overarching purpose of this thesis was to select and examine novel Bacillus strains for their potential as probiotics for poultry. The work showed Bacillus is a good source of probiotic bacteria and is safe to feed to poultry. These outcomes provided new insights into relationships between diet, probiotic species, and the intestinal microbiota of poultry.
3
Mutengwe, Rudzani Ruth. "Isolation and characterisation of a xylanase producing isolate from straw-based compost". Thesis, University of the Western Cape, 2012. http://hdl.handle.net/11394/4495.
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>Magister Scientiae - MScLignocellulosic biomass, a waste component of the agricultural industry, is a promising source for use in bioethanol production. Due to a complex structure, the synergistic action of lignocellulosic enzymes is required to achieve complete digestion to fermentable sugars. This study aimed to isolate, identify and characterise novel lignocellulase producing bacteria from thermophilic straw-based compost (71°C). Colonies with different morphological characteristics were isolated and screened for lignocellulosic activity. A facultative aerobic isolate RZ1 showed xylanase, cellulase and lipase/esterase activity. In addition to these activities, it was also able to produce proteases, catalases, amylases and gelatinases. RZ1 cells were motile, rod-shaped, Gram positive and endospore forming. The growth temperature of isolate RZ1 ranged from 25-55°C with optimal growth at 37°C. The 16S rRNA gene sequence was 99% identical to that of Bacillus subtilis strain MSB10. Based on the biochemical and physiological characteristics and 16S rRNA gene sequence, isolate RZ1 is considered a member of the species B. subtilis. A small insert genomic library with an average insert size of 5 kb was constructed and screened for lignocellulosic activity. An E.coli plasmid clone harbouring a 4.9 kb gDNA fragment tested positive for xylanase activity. The xyl R gene was identified with the aid of transposon mutagenesis and the deduced amino acid sequence showed 99% similarity to an endo-1-4-β-xylanase from B. pumilus. High levels of xylanases were produced when isolate RZ1 was cultured (37°C) with beechwood xylan as a carbon source. On the other hand, the production of xylanases was inhibited in the presence of xylose. Marked xylanase activity was measured in the presence of sugarcane bagasse, a natural lignocellulosic substrate. While active at 50°C, higher xylanase activity was detected at 37°C. Isolate RZ1 also produced accessory enzymes such as β-xylosidases and α-L-arabinofuranosidases, able to hydrolyse hemicellulose.
4
Zhao, Lingfeng. "Xylan removal by xylanase for the production of dissolving pulp from bamboo". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60269.
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With α-cellulose content and fiber characteristics similar to those of wood, bamboo is an attractive alternative feedstock for the production of dissolving grade pulp. A high level of hemicellulose in bamboo will lead to substantial complications in downstream processing of dissolving pulps into cellulose derivatives such as viscose, acetates, ethers etc. Xylanase treatment is an environment-friendly method that enables the selective removal of xylan (the major hemicellulose in bamboo) without detrimental effects on cellulose. In this study, we investigated a combination of mechanical refining with xylanase treatment for incorporation into a pre-hydrolysis kraft-based bamboo dissolving pulp production process. Laboratory PFI refining and xylanase treatment were combined to improve the xylan removal efficiency. Refining at 9000 revolutions increased the efficiency of subsequent enzymatic treatment resulting in a 44% removal of beta- plus gamma-cellulose with only 3 h of xylanase treatment. The alpha-cellulose content of bleached pulp prepared following combined refining-xylanase treatments was 93.37% (w/w) while the xylan content was only 2.38%. The properties of refined fibers prior to xylanase treatment, such as freeness, water retention value, fiber size and Scanning Electron Microscopy (SEM) images were investigated to further understand the underlying mechanism of the effect of refining on enzymatic treatment. The brightness, reactivity and viscosity of bleached bamboo dissolving pulp after ECF bleaching (D-EP-D) sequence were also evaluated. These results demonstrated the feasibility of combining refining and xylanase treatment to produce high quality bamboo dissolving pulp.Applied Science, Faculty of
Graduate
5
Gattinger, Loni D. "The enzymatic saccharification of canola meal and its utilization for xylanase production by Trichoderma reesei". Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5643.
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Tests made utilizing canola meal as a substrate for the production of xylanase indicate that Trichoderma reesei produced this enzyme in similar or better yields from canola meal than from expensive carbon sources such as Solka-floc, cellulose, glucose, lactose, sucrose or purified xylans. The effect of culture conditions on xylanase production when canola meal was used as a carbon source was also investigated. The enzyme system produced using canola meal also contained a higher proportion of acetyl-xylan esterase, cellulase, and xylosidase activities, most of which are required for synergistic action and hydrolysis of complex materials. The enzymatic saccharification of canola meal was also investigated. The results show that saccharification of canola meal is mainly brought about by hemicellulases capable of degrading arabinogalactan, arabinoglucan, galactan and galactomannan, while cellulase and xylanase play a minor role. This autoclaving pretreatment also released water soluble polysaccharides consisting mainly of arabinnose and glucose. T. reesei was unable to produce enzymes capable of hydrolyzing these polysaccharides when cultivated on canola meal as substrate. (Abstract shortened by UMI.)
6
Kalogiannis, Stavros. "Termoascus aurantiacus : identification of xylanolytic isozymes, characterization of the major endo-xylanase and use of the major endo-xylanase for the production of alkyl- and aryl-xylo-oligosaccharides". Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363495.
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Tremblay, Louis. "Production of a cloned xylanase gene in Bacillus cereus and its performance in kraft pulp prebleaching". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69517.
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Xylanase production from a Bacillus subtilis gene cloned into a strain of Escherichia coli was measured. Although this gene was expressed in E. coli at several temperatures, efficient normal xylanase secretion did not occur, the observed protein release apparently depending on cell leakage or lysis. Screening for a better microbial protein secretor free of cellulase selected B. cereus #259. The strain had wild plasmids that were hard to eliminate using acridine orange and elevated temperature curing techniques. While still bearing 5 wild plasmids, attempts to transform B. cereus #259 were unsuccessful using conventional methods and electroporation. Another strain, B. cereus #518, found to be free of wild plasmids, was then used. A bidirectional vector shuttle plasmid (pMK3) was employed to carry the cloned gene into this B. cereus strain. Transformation was carried out by high voltage electroporation. Xylanase production by the new B. cereus clone was similar to that from E. coli, but was shown to be continuously and normally secreted. The xylanase gene products from the E. coli and B. cereus hosts were shown to function identically. Both xylanases improved the delignification of unbleached softwood and hardwood kraft pulps, thus reducing the Cl$ sb2$ required to achieve a given degree of bleaching, without altering the physical properties of the fibers. Using a target kappa number lignin content) of 5, xylanase pretreatment of aspen kraft pulp led to a 22% saving of chlorine. Adsorbable organic halogens in the bleachery effluent were also lowered by more than 50%.
8
Yang, Yang. "Effects of Feeding Hulless Barley (Hordeum vulgare L.) and Supplementing a Fibrolytic Enzyme on Production Performance, Nutrient Digestibility, and Milk Fatty Acid Composition of Lactating Dairy Cows". Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85794.
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The overall objective of this study was to evaluate the effects of feeding hulless barley and supplementing a xylanase enzyme on production performance and nutrient utilization of lactating dairy cows. In study 1, we evaluated production performance, milk fatty acid composition, and nutrient digestibility in high-producing dairy cows consuming diets containing corn and hulless barley in different proportions as the grain source. We hypothesized that a plausible reduction in production performance would be explained by an altered rumen function, which would be reflected in a reduction of the proportion of de novo fatty acids in milk fat. The inclusion of hulless barley grain as the energy source in diets for lactating dairy cows resulted in similar production performance and nutrient utilization as corn grain. We concluded that hulless barley is as good as corn grain as an energy source and increasing NDF concentration in hulless barley-based diet is not necessary. In study 2, we evaluated production performance, nutrient digestibility, and milk fatty acid composition of high-producing dairy cows consuming diets containing hulled or hulless barley as the grain source. We hypothesized that rumen function is altered when cows are fed low-forage diets containing barley grains, and this altered rumen function would be reflected in lower production performance and a reduction of fatty acids synthesis in the mammary gland. Contrary to our expectations, feeding hulled barley or hulless barely based diets with different forage to concentrate ratios to lactating dairy cows resulted in similar production performance and nutrient utilization. We concluded that both hulled or hulless barley grains are good energy sources for sustaining high milk production and there is no need to increase NDF concentration in diet when using barley grain as the grain source. In study 3, we evaluated the effects of supplementing a xylanase enzyme on production performance and nutrient digestibility of lactating dairy cows fed diets containing corn or sorghum silage as the forage source. We hypothesized that supplementing a xylanase enzyme product in diets containing corn or sorghum silage increases NDF digestibility, and production performance of lactating dairy cows would also be improved due to enhanced fiber digestion. Supplementation of xylanase for 19 d did not affect cow performance and nutrient utilization. Supplementation of xylanase may require a longer period of time to show any response in production performance and nutrient digestibility. We concluded that supplementing xylanase to cows fed corn or sorghum silage-based diets did not improve fiber digestion. But for feeding hulled or hulless barley grains to lactating dairy cows, increased NDF concentration in diets is not necessary and hulless barley is good as corn grain for feeding lactating dairy cows as the grain source.Ph. D.
9
Ak, Ozlem. "Xylooligosaccharide Production From Cotton And Sunflower Stalks". Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609354/index.pdf.
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In this study, the aim was enzymatic xylooligosaccharide production from cotton and sunflower stalks, two of main agricultural residues in Turkey. In first two parts of the study, alkali extracted xylan from both of the stalks was hydrolyzed by commercial xylanases Veron and Shearzyme. The effect of temperature, pH, enzyme and substrate concentrations were investigated to determine optimum enzymatic hydrolysis conditions of xylan. Sunflower and cotton stalk xylans were hydrolyzed by Shearzyme more efficiently than Veron under the conditions studied. Shearzyme produced different product profiles containing xylobiose (X2), xylotriose (X3), xylotetrose (X4) and xylopentose (X5) from cotton and sunflower stalk xylan. On the other hand, Veron hydrolyzed both xylan types to
produce X2, X3, X5, X6 and larger xylooligosaccharides without any change in product profiles.
In the third part of the study, home produced xylanase from Bacillus pumilus SB-M13, was also investigated for the production of xylooligosaccharides from both cotton and sunflower stalk xylan. The main products obtained by hydrolysis of both substrates by pure B. pumilus xylanase were X5 and X6, while crude B. pumilus xylanase generated X4 and X5 as the main products.
Xylooligosaccharide production from pretreated cotton stalk without alkali extraction of xylan was the final part of the study. Three different pretreatment methods including biomass pretreatment by Phanerochaete chrysosporium fermentation, cellulase pretreatment and hydrothermal pretreatment were investigated to break down complex lignocellulosic structure of cotton stalk to improve the subsequent enzymatic hydrolysis of xylan in pretreated cotton stalk for xylooligosaccharide production. However, xylooligosaccharide was not effectively produced from pretreated cotton stalk. Shearzyme inhibiton was observed after all the pretreatment methods during further hydrolysis of pretreated cotton stalk probably due to production of inhibitory compounds of the enzyme.
10
Coffman, Anthony M. "Production of Carbohydrases by Fungus Trichoderma Reesei Grown on Soy-based Media". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1381761363.
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Schneider, Gerhard. "Production de xylanases par bacillus : métabolisme et procédé". Toulouse, INPT, 1999. http://www.theses.fr/1999INPT029G.
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Ce travail presente une etude de la croissance et de la synthese de xylanases d'une souche de bacillus dans l'objectif de proposer un procede fermentaire pour la production de l'enzyme. Les xylanases hydrolysent les xylanes, composants du bois, constituant en partie la liaison entre la cellulose et la lignine. Ces enzymes sont considerees comme une aide au blanchiment ecologique des pates a papier, car leur action favorise l'elimination de la lignine, responsable de la couleur du bois. Les xylanes etant des polysaccharides partiellement insolubles, la part soluble seulement a servi comme substrat. De ce fait, les micro-organismes peuvent etre separes du milieu de culture dans les echantillons, permettant la quantification de la biomasse et des solutes. Il a ete mis en evidence que la souche consomme des quantites importantes d'oxygene, necessitant des coefficients de transfert eleves, mais aussi que le dioxyde de carbone joue un role primordial de facteur de croissance. Ce role est assure par le dioxyde de carbone autochtone, mais s'il est enleve du milieu de culture par des conditions d'aeration vigoureuses, la souche ne se developpe pas. Lorsque le fermenteur est alimente avec de l'air enrichi a 1% de dioxyde de carbone, la duree des cultures est raccourcie de plus de la moitie. L'etablissement des bilans de matiere a revele que les bacteries utilisent d'abord comme source carbonee les peptones, puis, vers la fin de la phase de croissance, le xylane. Les cultures sans apport en dioxyde de carbone montrent une croissance diauxique nette sur ces deux substrats. Les xylanes sont indispensables pour l'induction de la production de xylanases, alors que leurs produits d'hydrolyse engendrent une repression catabolique de la synthese enzymatique. Des cultures discontinues alimentees avec limitation stricte en xylane ont permis de produire une concentration d'activite xylanasique de 20 240 nkat/ml avec une productivite de 910 nkat. Ml - 1. H - 1.
12
Bartonek-Roxå, Eva. "Recombinant peroxidases and xylanases I. Cloning and production of a peroxidase from horseradish : II. Characterisation of functional domains of thermostable xylanases from Rhodothermus marinus /". Lund : Lund University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/68945038.html.
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Gilbert, Michel. "Production and characterization of cellulases and xylanases from the thermophilic ascomycete Thielavia terrestris 255B". Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7918.
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Initially, we studied the production of cellulases and xylanases after growth of T. terrestris 255B on various substrates in order to obtain maximum production of these enzymes. We used non-denaturing electrophoretic techniques to compare the profile of enzymes produced on the various substrates. We found that T. terrestris 255B produced two major and at least 5 minor endoglucanase components. We discussed the possibility that some of these components might exist as multi-enzyme complexes that were difficult to isolate in an intact form. We purified two cellobiohydrolases and one $\beta$-glucosidase which were all partially characterized. One of the cellobiohydrolases (CBHII) seemed to be a major component of the cellulase system as it accounted for about 40.8% of the observed activity when crystalline cellulose was used as the substrate. T. terrestris 255B produced two major forms of xylanases with pI's of 4.6 (xylanase I) and 6.1 (xylanase II). The latter enzyme could be purified to $>$99% homogeneity using anion-exchange chromatography and gel filtration. Xylanase II had a molecular mass of 25.7 kDa (SDS-PAGE) and optimal pH and temperature of 3.6-4.0 and 60-65$\sp\circ$C, respectively. The activity of xylanase II was very specific towards the hydrolysis of xylan and had extremely low activity on cellulose. Thus, as it had potential application for the pre-bleaching of kraft pulps, the characterization of this enzyme became the main focus of the work. We used amino acid composition and partial amino acid sequencing to demonstrate that xylanase II belonged to a family of low molecular weight xylanases which had been previously designated the G family by Gilkes et al. (1991b). Currently, xylanase II is the only thermophilic xylanase that has been shown to belong to the G family of $\beta$-1,4-glycanases. Xylanase II has one disulfide bridge and it is possible that this might account for its higher thermostability when compared to the other members of the G family. We studied the mode of action of xylanase II and compared it with a 32-kDa xylanase derived from Thermoascus crustaceus. This latter enzyme is a thermophilic xylanase which appears to belong to the F family of $\beta$-1,4-glucanases. Xylanase II was more efficient at solubilizing insoluble xylan and yielded hydrolysis products with higher degrees of polymerization than the 32-kDa xylanase. Xylanase II could not cleave xylotriose although it cleaved xylotetraose to xylobiose and xylotriose using a process involving transxylosidation. The 32-kDa xylanase could cleave both xylotriose and xylotetraose to xylobiose and xylose. Xylose was a major product of xylan hydrolysis by the 32-kDa xylanase while it was only a minor product when the hydrolysis was performed with xylanase II. Although xylanase II and the 32-kDa xylanase seem to belong to different families of xylanases and had different modes of action, they did not show any cooperative hydrolysis action when they were added to xylans from various sources (cereal, hardwoods and softwoods). The profile of products obtained when the two thermophilic xylanases were used together was almost identical to the profile obtained when the 32-kDa xylanase acted alone. (Abstract shortened by UMI.)
14
Pham, Phuong Lan. "Production de xylanases par Bacillus. Application au blanchiment sans chlore des pâtes à papier". Toulouse, INPT, 1996. http://www.theses.fr/1996INPT043G.
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Le blanchiment conventionnel au chlore et au dioxyde de chlore des pates a papier a un effet nefaste sur l'environnement a cause de la presence de composes organo-chlores dans les effluents. L'industrie papetiere est aujourd'hui confrontee a une croissance des pressions antipollution. Un grand nombre de progres a ete realise ces dernieres annees. Parmi les nouvelles technologies de blanchiment, l'emploi des endoxylanases apparait comme une voie prometteuse. L'application de ces enzymes a pour consequence: ? une reduction des reactifs de blanchiment necessaires pour atteindre une blancheur elevee ; ? une augmentation considerable de la blancheur des pates a papier. L'objectif de ce travail a consiste a selectionner une souche bacterienne capable de produire des xylanases. Ces enzymes doivent etre applicables au blanchiment sans chlore des pates a papier. La production des xylanases par quatre bacteries du genre bacillus (deux souches de b. Polymyxa et deux autres issues de bacillus sp. ) est etudiee. Parmi ces souches, bacillus sp. I-1018 est selectionnee pour la suite en raison de sa capacite a secreter une activite xylanasique plus elevee. L'influence de nombreux parametres de culture (sources de carbone et d'azote, differentes vitesses d'agitation et debits d'aeration, ph, temperature, taux d'inoculum) est egalement examinee. Une augmentation en xylanase de 156% est constatee lorsque la bacterie se developpe sur le milieu qui est optimise grace a l'utilisation de plan d'experiences. Dans une deuxieme partie, l'application des xylanases dans la sequence complete de blanchiment combinant l'ozone et l'eau oxygenee a ete envisagee. Cette etude a porte a la fois sur l'enzyme produite par la souche que nous avons selectionne et sur une enzyme commerciale. Elle a demontre que l'utilisation des xylanases permet de diminuer la quantite des reactifs chimiques necessaires et d'ameliorer considerablement la blancheur des pates. De plus, ces resultats indiquent qu'un tel traitement n'affecte pas la resistance physique des pates grace a l'absence totale d'activite cellulasique. Les performances de l'enzyme que nous avons produite sont tres sensiblement superieures a celles de l'enzyme commerciale. En conclusion, l'etude a permis de choisir une souche de bacterie hyper-productrice de xylanase, d'optimiser les conditions de production de l'enzyme et de proposer une sequence de blanchiment ou le traitement enzymatique est integre
15
Adeoyo, Olusegun Richard. "Bioprospecting for amylases, cellulases and xylanases from ericoid associated fungi, their production and characterisation for the bio-economy". Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/64327.
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Cadete, Sonia Marisa Silva. "Enzymatic upgrading of eucalypt paper-grade kraft pulp within dissolving pulp production". Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16089.
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Mestrado em Biotecnologia - Biotecnologia Industrial e AmbientalDissolving-grade pulps are commonly used for the production of cellulose derivatives and regenerated cellulose. High cellulose content, low content of non-cellulosic material, high brightness, a uniform molecular weight distribution and high cellulose reactivity are the key features that determine the quality of a dissolving pulp. The first part of this work was an optimization study regarding the application of selected enzymes in different stages of a new purification process recently developed in Novozymes for purifying an eucalypt Kraft pulp into dissolving pulp, as an alternative to the pre-hydrolysis kraft (PHK) process. In addition, a viscosity reduction was achieved by cellulase (endoglucanase) treatment in the beginning of the sequence, while the GH11 and GH10 xylanases contributed to boost the brightness of the final pulp. The second part of the work aimed at exploring different auxiliary enzyme activities together with a key xylanase towards further removal of recalcitrant hemicelluloses from a partially bleached Eucalypt Kraft pulp. The resistant fraction (ca. 6% xylan in pulp) was not hydrolysable by the different combinations of enzymes tested. Production of a dissolving pulp was successful when using a cold caustic extraction (CCE) stage in the end of the sequence O-X-DHCE-X-HCE-D-CCE. The application of enzymes improved process efficiency. The main requirements for the production of a dissolving pulp (suitable for viscose making) were fulfilled: 2,7% residual xylan, 92,4% of brightness, a viscosity within the values of a commercial dissolving pulp and increased reactivity.
Pastas solúveis são normalmente usadas para a produção de derivativos de celulose e celulose regenerada. Alguns dos parâmetros que determinam a qualidade de uma pasta solúvel são: um elevado teor de celulose, baixo teor de material nãocelulósico, elevada brancura, uma distribuição uniforme de pesos moleculares e elevada reactividade da celulose. Na primeira parte deste trabalho, fez-se um estudo de optimização aplicando enzimas, previamente seleccionadas, em diferentes fases de um novo processo de purificação desenvolvido na Novozymes da pasta de eucalipto Kraft em celulose solúvel, como uma alternativa ao processo convencional de pré-hidrólise kraft. Além da purificação, a aplicação de celulases (endoglucanase) no início da sequência possibilitou uma diminuição da viscosidade, enquanto que a aplicação de xilanases das famílias GH11 e GH10 contribuíram também para o aumento da brancura da pasta final. A segunda parte deste trabalho teve como objectivo explorar várias actividades enzimáticas auxiliares conjuntamente com a melhor GH11 xilanase identifcada, de modo a promover a remoção das hemiceluloses mais recalciterantes de uma pasta Kraft de Eucalipto parcialmente branqueada. Todas as combinações das enzimas testadas resultaram numa fracção resistente de xilana residual (ca. 6% na pasta) que não foi possível hidrolisar. A produção de uma pasta solúvel foi possível usando um estágio de extracção alkalino a frio (CCE) no fim de uma sequência composta pelos seguintes estágios: O-X-D-HCE-X-HCE-D-CCE. A aplicação de enzimas melhorou a eficiencia do processo. Com esta sequência,os principais requisitos para a produção de uma pasta solúvel (adequada para producao de viscose) foram cumpridos: 2,7% de xilana residual, 92,4% de brancura, uma viscosidade dentro dos valores de uma pasta solúvel comercial e elevada reactividade.
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Knob, Adriana. "Complexo xilanolítico de Penicillium sclerotiorum : produção, purificação e caracterização de xilanases e de ß-xilosidases /". Rio Claro : [s.n.], 2009. http://hdl.handle.net/11449/103952.
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Orientador: Eleonora Cano CarmonaBanca: Aline Aparecida Pizzirani Kleiner
Banca: Helia Hamuri Sato
Banca: Rosa dos Prazeres M.F. Inocentes
Banca: Marcia Regina Brochetto Braga
Resumo: Enzimas degradadoras de xilana, principal componente da hemicelulose, têm sido utilizadas em várias aplicações biotecnológicas, sendo que em alguns processos é necessário o uso de enzimas purificadas. Aplicações comerciais para as enzimas xilanolíticas envolvem a hidrólise enzimática da xilana, que está presente nos resíduos agrícolas e agroindustriais, sendo convertido a xilose e outros açúcares, que podem ser utilizados como substratos em processos fermentativos para a obtenção de proteínas celulares, combustíveis líquidos e outras substâncias químicas. A utilização destas enzimas também diminui a liberação de agentes poluentes em determinados efluentes, como da indústria de polpa de celulose. Xilanases e β- xilosidases são produzidas principalmente por bactérias e fungos, sendo que em geral, os fungos as produzem em níveis mais elevados. O gênero Penicillium apresenta espécies já caracterizadas como boas produtoras destas enzimas. Uma linhagem deste gênero, isolada de solo brasileiro, na região da Mata Atlântica e identificada como Penicillium sclerotiorum destacou-se por produzir xilanase em níveis elevados. O objetivo deste trabalho consistiu na avaliação da influência das condições de cultivo sobre a produção do complexo xilanolítico produzido por P. sclerotiorum, na caracterização físico-química desse sistema, bem como purificação e caracterização bioquímica de seus principais componentes. Por meio da determinação das condições ótimas de produção e da caracterização deste complexo enzimático foi possível estabelecer metodologias eficientes de purificação de xilanases e uma β-xilosidase. Através da caracterização físico-química das enzimas purificadas, foi possível avaliar seu potencial biotecnológico, visando futuras aplicações em processos industriais.
Abstract: Xylan degrading enzymes, the main component of hemicellulose, have been used in various biotechnological applications, and in some cases the use of purified enzymes is necessary. Commercial applications of xylanolytic enzymes involve the enzymatic hydrolysis of xylan, which is present in agricultural and agro-industrial wastes, and can be converted to xylose and other sugars, which can be further used as substrates in fermentation processes to obtaining cellular protein, liquid fuels and other chemicals. The utilization of these enzymes also decreases the release of certain pollutants in wastewater, as in the pulp and paper industry. Xylanases and β-xilosidases are mainly produced by bacteria and fungi, and in general, the fungi produce them at higher levels. The genus Penicillium presents species already characterized as good producers of these enzymes. One strain of this genus isolated from Brazilian soil in the Mata Atlântica region and identified as Penicillium sclerotiorum attracted attention by producing xylanase in high levels. The objective of this study was to evaluate the influence of culture conditions on the production of the xylanolytic complex produced by P. sclerotiorum to characterize physical and chemical properties of this system as well to purify and biochemical characterize its main components. By determining optimal conditions for production and by characterizing this enzymatic complex it was possible to establish efficient methodologies for purification of xylanases and one β-xylosidase. Through their physical and chemical characterization, it was possible to evaluate their biotechnological potential for future applications in industrial processes.
Doutor
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Knob, Adriana [UNESP]. "Complexo xilanolítico de Penicillium sclerotiorum: produção, purificação e caracterização de xilanases e de ß-xilosidases". Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/103952.
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Enzimas degradadoras de xilana, principal componente da hemicelulose, têm sido utilizadas em várias aplicações biotecnológicas, sendo que em alguns processos é necessário o uso de enzimas purificadas. Aplicações comerciais para as enzimas xilanolíticas envolvem a hidrólise enzimática da xilana, que está presente nos resíduos agrícolas e agroindustriais, sendo convertido a xilose e outros açúcares, que podem ser utilizados como substratos em processos fermentativos para a obtenção de proteínas celulares, combustíveis líquidos e outras substâncias químicas. A utilização destas enzimas também diminui a liberação de agentes poluentes em determinados efluentes, como da indústria de polpa de celulose. Xilanases e β- xilosidases são produzidas principalmente por bactérias e fungos, sendo que em geral, os fungos as produzem em níveis mais elevados. O gênero Penicillium apresenta espécies já caracterizadas como boas produtoras destas enzimas. Uma linhagem deste gênero, isolada de solo brasileiro, na região da Mata Atlântica e identificada como Penicillium sclerotiorum destacou-se por produzir xilanase em níveis elevados. O objetivo deste trabalho consistiu na avaliação da influência das condições de cultivo sobre a produção do complexo xilanolítico produzido por P. sclerotiorum, na caracterização físico-química desse sistema, bem como purificação e caracterização bioquímica de seus principais componentes. Por meio da determinação das condições ótimas de produção e da caracterização deste complexo enzimático foi possível estabelecer metodologias eficientes de purificação de xilanases e uma β-xilosidase. Através da caracterização físico-química das enzimas purificadas, foi possível avaliar seu potencial biotecnológico, visando futuras aplicações em processos industriais.
Xylan degrading enzymes, the main component of hemicellulose, have been used in various biotechnological applications, and in some cases the use of purified enzymes is necessary. Commercial applications of xylanolytic enzymes involve the enzymatic hydrolysis of xylan, which is present in agricultural and agro-industrial wastes, and can be converted to xylose and other sugars, which can be further used as substrates in fermentation processes to obtaining cellular protein, liquid fuels and other chemicals. The utilization of these enzymes also decreases the release of certain pollutants in wastewater, as in the pulp and paper industry. Xylanases and β-xilosidases are mainly produced by bacteria and fungi, and in general, the fungi produce them at higher levels. The genus Penicillium presents species already characterized as good producers of these enzymes. One strain of this genus isolated from Brazilian soil in the Mata Atlântica region and identified as Penicillium sclerotiorum attracted attention by producing xylanase in high levels. The objective of this study was to evaluate the influence of culture conditions on the production of the xylanolytic complex produced by P. sclerotiorum to characterize physical and chemical properties of this system as well to purify and biochemical characterize its main components. By determining optimal conditions for production and by characterizing this enzymatic complex it was possible to establish efficient methodologies for purification of xylanases and one β-xylosidase. Through their physical and chemical characterization, it was possible to evaluate their biotechnological potential for future applications in industrial processes.
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Hsieh, Meng Chou, i 謝孟洲. "Estimation of simultaneous production for xylanase/phytase and optimal production of xylanase from Aspergillus carneus M34". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/46760344500471002172.
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碩士國立中興大學
食品科學系
92
The objective of this study was to evaluate the possibility of enhancement of xylanase and phytase activity simultaneously from Aspergillus carneus M34 and to establish the optimal conditions for xylanase production by using experimental design methodology. The effects of nutrition on the enzyme activity were evaluated, and then the important factors were selected through fractional factorial design. The steepest ascent design was used to establish the superior conditions for xylanase production. Effects of the phosphorous source, culture temperature, and initial pH on the xylanase activity were evaluated as well. The optimal enzyme activity was obtained by central composite design. The results from the phosphorous source, carbon source, and experiment design studies showed that both of xylanase and phytase activity could not be improved simultaneously by selecting the nutritional factors and their concentrations. Xylanase activity was estimated to be 11.66 U/ ml by the mathematic model of central composite design, and the stationary point was found to be a saddle point. The optimal conditions for the xylanase activity from A. carneus M34 are as follows: 1.5% hemicellulose (from coba husk), 0.8 % yeast extract, 0.4% ammonium chloride, initial pH at 7.00, incubation temperature at 30℃. After 5 days of cultivation, the maximal enzyme activity was 27.31±1.14 U/ ml.
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Chang, Hui-Fen, i 張惠芬. "Production of thermotolerant xylanase in Paenibacillus macerans". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/19061899797254831960.
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碩士國立臺灣大學
生化科技學系
102
Our reports showed that when cultured in 500 mL Hinton’s flask, the optimum temperature for Paenibacillus macerans is 30℃, the optimum pH of induction medium is pH 7.0, and the optimum induction temperature is 45℃. The xylanase of P. macerans was optimally active at 55℃ and pH 4.5. Compared with glucose, maltose, and xylose, the most suitable carbon source in growth stage was glycerol. Compared with bagasse, soya powder, white poplar powder, and beechwood xylan, the best carbon source we investigated to induce xylanase activity was wheat bran. While grown for 20 hours at 37℃, we added wheat bran to start induction phase, and rising temperature to 45℃ at the same time, continuing to culture for 34 hours, having the xylanase with the concentration of 15 IU/mL. To scale up, we cultured P. macerans in the 5 L bioreactor. While grown for 9.5 hours at 37℃, we added wheat bran, and rising temperature to 45℃, continuing to culture for 28 hours, having the xylanase activity with 15 IU/mL. Compared with flask culture, we could obtain the same amount of xylanase with shortened incubation time of 16.5 hours. Coordinated with laccase, we carried out functional assay─the bio-bleaching of pulp. The xylanase significantly reduced kappa number by 3.7 units, and increased the ISO brightness by 2%. We used 4 conserved sequences of glycoside hydrolase family 11 (GH11) and genome-walking technique to acquire xylanase nucleotide sequence in moderately thermophilic bacterium P. macerans. A xylanase gene of 633 bp was cloned that encodes a protein containing 211 amino acid residues. When the xylanase gene was cloned and expressed in Escherichia coli M15/pREP4, we used anti-His taq antibody to detect the recombinant protein, figuring out the recombinant strain produced almost all the xylanase in the inclusion body, even after long-time induction at low temperature. The soluble protein in the supernatant after sonication showed low xylanase activity, even concentrated. The xylanase of P. macerans is one of the rare xylanases that exhibits thermo- and acid stability, and thus, it is a suitable candidate for pre-bleaching of paper pulps and generating xylooligosaccharides from agro-residues for use as prebiotics.
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Fang, Hsin-Yu, i 方信裕. "Xylanase from Aspergillus carneus M34: production, purification, and application". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/16991209140794521414.
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博士國立中興大學
食品暨應用生物科技學系
96
Xylanase from Aspergillus carneus M34 and its application in functional oligosaccharides preparation were investigated in this thesis. Growth conditions, including incubation times, temperature, agitation rate and initial pH of medium, that affect growth and xylanase production by Aspergillus carneus M34 were studied. Response surface methodology (RSM) was further introduced to optimize the cultivation conditions and to evaluate the significance of these factors. The optimal cultivation condition derivate from this model is 35.08 degree C of incubation temperature, 111.9 rpm of agitation rate, an initial medium pH of 5.16 and 3 days of cultivation time. In addition, temperature was the most critical factor for xylanase production by A. carneus M34. Xylanase activity with 22 U/mL was verified from predicted optimal conditions, which was 20% increase compared to originanl cultivation conditions. Considering of its higher specificity toward agricultural wastes, especially corn cob and coba husk, this strain can be adopted in developing low-cost media for the mass-production of xylanase or xylo-oligosaccharides preparation. To fully understand the potential industrial application of xylanase from this strain, purification and characterization of the extracellular xylanase from the culture were performed. A low-molecular-weight xylanase, approximately 18.8 kDa with a pI value of 7.7–7.9, was purified by ammonium sulfate precipitation, DEAE-Sepharose CL-6B and Sepharacyl S-200 in sequentially in this work. The optimum temperature and pH of this purified xylanase activity were 50oC and 6, respectively. The xylanase was more stable under alkaline conditions and retained more than 50% activity after 12 hours incubation at pH 7–9. The half-lives (t1/2) of the xylanase inactivation at 50oC, 55oC, and 60oC were 142.3 minutes, 8.6 minutes, and 5.6 minutes, respectively. The purified xylanase had no carboxymethylcellulase (CMCase), cellulase, α-L-arabinofuranosidase, β-galactosidase or β-xylosidase activities. These results indicate that this xylanase is a true xylanase. Considering of its characteristics and N-terminal similarity, this xylanase was concluded as a new one belonging to the family 11 glycosylase and can be further categoried into the group I of family 11 endoxylanases. Profiles of the xylanase hydrolysis products, no xylose was produced after 24 h, indicate that the xylanase is an endo-acting enzyme and suitable for xylo-oligosaccharides preparation. Based on the agricultural wastes usage, hemicellulose of coba husk was selected for preparation of xylooligosaccharides with antioxidation capacity due to its higher substrate specificity. Experiments were conducted with cell model of keratinocyte xb-2 with UVB served as the source of oxidative stress. From the LDH assay, enzymatic extracts show more photoprotective capacity than substrate. This implied the antioxidation capacity is existed in the enzymatic extracts. Since ferulic acid is the most abundant polyphenolic acid in the cell wall, feruloyl xylo-oligosaccharides were separated from pure xylanase extracts by XAD-2 chromatography and to identify its antioxidation capacity. The antioxidation capacity of feruloyl xylooligosaccharides was evidenced from its ferulic acid moiety in DPPH radical scavenge test, and exhibited more efficient against UV damage than vitamin C in the UVB-induced oxidative damage cell model.
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Shin, Wen-Li, i 施文吏. "Production and Characterization of Xylanase from Trichoderma Longibrachiatum Mutant 2047". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/11821932169352988258.
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碩士國立中興大學
食品科學研究所
86
The fungus Trichoderma longibrachiatum 185 capable of producing high xylanase was used as parent strain in this study to genetically improve its enzyme producing capability further through the ultraviolet light irradiation. The mutant with xylanase-producing ability was screened by a selective medium containing RBB-xylan as carbon source. Finally, mutant 2047 was chosen out of about 200 mutants. Xylanase production by the mutant 2047 was approximately 1.3-fold higher than that of wild type. T.longibrachiatum mutant 2047 was cultivated in shaking flasks(capacity 500 ml), and a better medium composition for xylanase production was determined to be the same with that of wild type. For cultivation condition, the Mandels-Reese medium with oat spelt xylan at 0.5% as carbon source, initial pH at 6.0, inoculum size at 105 spores/ml, incubation temperature at 35℃, and shaking rate at 130 rpm gave the best result for the enzyme production. The maximum xylanase activity of 4.0 U/ml in the culture broth was obtained after 5 days under above condition. Combination of nitrogen sources, 0.14%(NH4)2SO4+0.1% Peptone+0.03 Urea, was the best nitrogen source for the maximum xylanase production (4.2U/ml), while less enzyme production was found if urea alone at 0.73% was used (3.2U/ml). The xylanase from mutant 2047 was purified by ammoniurm sulfate precipitation(30-50%)、ion exchange chromatography and gel filtration chromatography. Two distinct bands were found in SDS-PAGE chromatogram of purified xylanase, this indicated the xylanase was composed of two subunits. In addition, molecular weights of subunits were larger than those from parent strain. The optimal pH and temperature for the purified xylanase were 5-6 respectively. Some enzymatic parameters Such as Km, Vmax and action mode were found to be identical with those from parent strain and 45℃, The respective value of Km and Vmax were 10.10 mg xylose ml-1 and 4008U/mg, and the action mode of purified enzyme was endo-type.The thermal stability of xylanase was better than that of parent strain, as the residual activity remained to have 80% after the enzyme had been incubated at 45℃ for 6h.
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Liao, Chia-Wei, i 廖佳瑋. "Studies on the optimal production of xylanase from Aspergillus carneus M34". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/16366915538224826174.
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碩士國立中興大學
食品科學系
88
Hemicellulose is abundant in nature and consists largely of xylan. It can be hydrolyzed by xylanase to xylooligosaccharides and xylose which can serve as sweetener or even be converted to chemicals, organic solvents and other useful products. Plant biomass seems to be a good renewable resource if we use it well. In this study, Aspergillus carneus M34, which was isolated from soil by our laboratory and had ability to produce xylanase, was used to study the production and characterization of xylanase. Aspergillus carneus M34 was cultivated in shaking flasks and a better medium for xylanase production was determined by response surface methodology as follows: birchwood xylan, 1.5%; peptone, 0.6%; Tween 80, 0.2%; KH2PO4, 0.2%; CaCl2, 0.03%; MgSO4∙7H2O, 0.03%; FeSO4∙7H2O, 0.0005%; MnSO4∙H2O, 0.00016%; ZnSO4∙7H2O, 0.00014%; CoCl2, 0.0002%. For cultivation condition, initial pH at pH 8.6, incubation temperature at 40℃, and a shaking rate at 130 rpm showed a better result in enzyme production. The maximal xylanase activity of 48 U/mL was obtained after 3 days of incubation under the above conditions. The optimal pH of crude xylanase activity was pH 7.0, and the optimal temperature for this enzyme was 50-60℃. The results of thermostability study of this enzyme showed that 50% of activity was retained after incubated at 50℃ for 1h; however nearly no activity was found when the crude enzyme was incubated at 60℃ for 1h. The activities of A. carneus M34 xylanase showed high specificity on hydrolysis of xylans which come from birchwood and oat spelt.
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朱文銘. "Studies on the production and properties of xylanase from Aspergillus niger NCH-3". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/53952507916307216810.
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碩士國立中興大學
食品科學系
87
A high xylanase producing mold, strain NCH-3 was isolated from Taiwan soil. According to morphologic characterization of strain NCH-3 grown on CZ and MEA media, it was identified to be the same as a type culture of Aspergillus niger and was named temporarily as Aspergillus niger NCH-3. The optimal medium composition and cultivation conditions for A. niger NCH-3 was determined in shaking flasks (capacity 500 ml). The results showed that the Mandels-Reese medium with oat spelt xylan at 0.75% as carbon source, 0.38% KNO3 as nitrogen sources, initial pH at 8.0, inoculum size at 105 spores/ml, incubation temperature at 35 ℃, and shaking rate at 130 rpm gave the best result for the enzyme production. The maximum xylanase activity of 26.17 U/ml in the culture broth was obtained after 5 days under above conditions. The broth filtrate from A. niger NCH-3 was purified by ammonium sulfate precipitation (40-70%)、ion exchange chromatography and gel filtration chromatography. The purified enzyme appeared as single protein band on SDS-PAGE with molecular weight of 35 kDa. The isoelectric point of purified xylanase was 4.0. The optimum pH of activity was pH 5.0；howere, the enzyme remained quite active in pH ranging from pH 5.0 to 7.0. Both thermal stability and optimal temperature for purified xylanase were at 50℃. Enzyme showed high specificity on hydrolysis of xylans which came from beech wood, birch wood and oat spelt . The activity of xylanase was inhibited by Hg2+ ion, while Mn2+ and -mercaptoethanol at concentrations of 5mM stimulated the enzyme activity. It was suggested that the sulfhydryl (-SH) group in the protein molecule was located at or near the active site, and probably involved in the hydrolysis reaction catalyzed by the enzyme.
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Lu, Wei-chung, i 呂維鈞. "Development and application of xylanase: Strain isolation, enzyme production and purification, and feedstock preparation for cellulosic biohydrogen production". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/49882651468879811803.
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碩士國立成功大學
化學工程學系碩博士班
97
A cellulolytic bacterial strain was isolated from soil taken from southern Taiwan and identified as Acinetobacter junii F6-02 via phylogenetic and 16S rRNA sequencing analysis. Investigation of cellulases and xylanase production of Acinetobacter junii F6-02 showed that the activity of those cellulolytic enzymes were mainly located extracellularly. The optimal temperature and pH for xylanase activity 60oC and 7, respectively, while the best condition for xylanase production by A. junii F6-02 was 35oC, and 0.3 vvm aeration speed was the best xylanase production condition. The best carbon source concentration and nitrogen source to optimize xylanase production was 5 g/L each for CMC and xylan and peptone 1 g/L. Lyophilized enzyme bioagent produced from Acinetobacter junii displays better xylanase ability than supernatant of the fermentation broth. The enzyme bioagent displayed a stable long-term hydrolysis at a temperature of 50oC. Xylanase purification via FPLC shows that two xylanase enzymes exist in the supernatant of Acinetobacter junii and their molecular weight is about 70 and 85 kDa. The vmax and Km of xylanase with the substrate of xylan and NaOH pretreated straw was 8.6 g/L/h, 10.6 g/L and 3.6 g/L/h, 26.9 g/L, respectively. Batch H2 fermentation with Clostridium butyricum CGS5 shows that using hydrolysate of xylan and NaOH pretreated rice straw as the substrate, the maximum H2 production rate was 62.5 and 26.8 ml/h/L, respectively, and maximum H2 yield were 0.70 and 0.76 mol H2/mol xylose, respectively. Simultaneous enzymatic xylan saccharification and hydrogen fermentation was also investigated. Under a reaction temperature of 37oC, the hydrogen production rate reached a maximum value of 35.3 ml/h/L, which is markedly lower than that obtained from the two-stage process.
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Ntuli, Sifiso Theophilus. "Production of xylanase enzyme from sulphite liquor using an airlift reactor with internal loop". Thesis, 2009. http://hdl.handle.net/10413/886.
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Chen, Zhao Ling, i 陳昭伶. "Studies on the production, purification and characterization of a xylanase from trichoderma sp. 185". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/36487503896140090521.
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Tang, Wan-Ju, i 湯惋茹. "Optimization of xylanase production and characterization by Aspergillus carneus M34 in solid state fermentation". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/17058480653643917012.
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碩士國立中興大學
食品科學系
92
Xylan is present in large amounts in agriculture wastes. It can use xylanase for conversion into several useful products such as xylose, xylooligosaccharide. In this study, a xylanase—producing strain, Aspergillus carneus M34, which was isolated from soil by our laboratory, was used to study the growth condition for optimal xylanase production, enzyme characterization and extraction methods by solid state fermentation. The better medium composition for xylanase production of A. carneus M34 was determined by response surface methodology as follows: initial moisture content, 75.8％；yeast extract, 0.21 g/ 5g substrate；and NH4NO3, 0.084 g/ 5g substrate. For cultivation condition, coba husk was used for substrate, incubation temperature at 30℃, inoculum 106 spores / ml, yeast extract o.2 g, and initial moisture content at 75％ were showed a better result in enzyme production. The maximal xylanase activity of 981 U/g was obtained after 12 days of incubation under the above conditions. The optimal temperature and pH for crude enzyme were 50-60℃and pH 6, respectively. In respect to thermostability, the residual activity of xylanase was 80％ at 50℃ for 1 hour. It also exhibited a good pH stability at range of 5 to 7. 100 ml of 0.1％ Tween 80, and shaked at 200 rpm were used for extraction 1 hour.
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Thorulsley, Venessa. "Development of a flat sheet woven fabric membrane fermenter for xylanase production by Thermomyces lanuginosus". Thesis, 2015. http://hdl.handle.net/10321/1381.
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Submitted in fulfilment of the requirements for the degree of Master of Engineering, Durban University of Technology, Durban, South Africa, 2015.Fermentation processes are vital for the production of numerous bioproducts. Fermentation being the mass culture of micro – organisms for the production of some desired product, is an extensive field, with immense prospects for study and improvement. Enzyme production is of significance as these proteins are biological catalysts, finding niches in numerous industries, xylanase for example is utilized in the pulp and paper, animal feed, biofuel and food production processes. During enzyme production, a critical step is biomass separation, whereby the valuable product, the enzyme, is removed from the broth or micro – biological culture before it is denatured. This is typically achieved via centrifugation. The aim of this study was to develop and evaluate a submerged membrane fermenter system with the specific outcome of increasing the rate of production of xylanase, from the thermophilic fungal species Thermomyces lanuginous DSM 5826. Preliminary shake flask experiments were performed to determine the optimal production conditions, followed by partial characterization of the enzyme. A bioreactor was then fabricated to include a flat sheet membrane module, with outlets for permeate and broth withdrawal and inlets for feed and sterile air input. Experiments were conducted to determine the optimal dilution rate for maximum volumetric productivity. Results from the shake flask experiments indicated that the best conditions for xylanase production, yielding xylanase activity of 5118.60 ± 42.76 U.mL-1 was using nutrient medium containing beechwood xylan (1.5 % w/v), yeast extract (1.5 % w/v), potassium dihydrogen phosphate (0.5 % w/v), adjusted to a pH of 6.5 and inoculated with 1.0 mL of spore solution, rotating in a shaking incubator set to 150 rpm at 50 °C. Apart from analysis of the effect of the carbon source on xylanase activity, coarse corn cobs were used in the shake flask experiments as a cost saving initiative. The pH optima was determined to be 6.5 while the temperature optima of the enzyme was 70 °C. SDS PAGE analysis revealed that the molecular weight of the enzyme was between 25 and 35 kDa and qualitative analysis via a zymogram revealed clear zones of hydrolysis on a xylan infused agarose gel. During short run membrane fermenter experiments the percentage increase in enzyme activity between the batch operation (610.58 ± 34.54 U.mL-1) and semi – continuous operation (981.73 ± 55.54 U.mL-1) with beechwood xylan nutrient replenishment was 60.78 %. The maximum volumetric productivity achieved with beechwood supplementation after 192 hours in semi – continuous operation (5.32 ± 0.30 U.mL-1.hr-1) was 2.1 times greater than that of batch operation (2.54 ± 0.14 U.mL-1.hr-1) which equates to an increase of 110.28 % in productivity measured at its peak. The increase in total activity between batch (610 576.92 U) and beechwood xylan medium supplemented semi – continuous mode (1 184 937.50 U) resulted in a 94.07 % increase. During long run experimental periods, the increase in production of xylanase between the batch (873.26 ± 61.78 U.mL-1) and the xylan medium membrane system (1522.41 ± 107.65 U.mL-1) was determined to be 74.34 % while an overall average increase in productivity between the batch and xylan fed membrane system was 43.25%. The total enzyme activity with in membrane mode with beechwood xylan nutrient medium feed was 160 % greater than the batch process offering a 2.6 – fold increase. Experiments where de – ionized water was alternated with beechwood xylan nutrient medium had no significant impact on the productivity or enzyme activity. The optimal dilution rate for maximum volumetric productivity as determined to be 0.0033 hr-1. The results are indicative of the potential viability of such a design, yielding the desired outcome of a membrane integrated system to significantly increase the production of enzymes during fermentation.
30
Liao, Bo-Chin, i 廖柏欽. "Xylanase and xylooligosaccharides production by Aspergillus carneus M34 in solid state fermentation using low cost substrate". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/36274959519497859906.
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碩士國立中興大學
食品科學系
93
The aim of this study was to develop a cost-down solid-state fermentation process for xylanase production from Aspergillus carneus M34. In addition, effects of various environmental conditions on the degradative activities of agricultural waste to produce xylooligosaccharides by the immobilized xylanase were evaluated as well. In order to increase the xylanase activity of A. carneus M34, several strategies such as low cost agricultural wastes as the carbon sources and increasing inoculum size were used. For optimization of the medium composition, experimental designs including Plackett-Burman and response surface methodology (RSM) were practiced. The results showed that when agricultural waster of coba husk and corn steep liquor was used in the ratio of 4.5:0.5, a 1.2 fold of increase in xylanase activity was observed. The incubation time for the xylanase production can be reduced from 12 days to 6 days by increasing the inoculum size at 2 × 107 spores/ml. The optimal medium compositions were as follows by using experimental designs including P lackett-Burman and RSM: carbon source, coba husk and corn steep liquor (4.5:0.5); NH4NO3, 3.24%; CaCl2, 0.1336%; MnSO4·7H2O, 0.001239%. Xylanase activity of 1721 U/g substrate can be produced by A. carneus M34 in 6 day by using this medium composition. We found that chitosan was the most suitable material to immobilized xylanase in this study, which with increase thermo-stability of the enzyme. For enzyme degradation of agricultural wastes including tea leaves, coba husk, bamboo, rice husk, soybean dregs, root of bamboo, bagasse, wheat bran and rice bran treated with alkaline and xylanase, 17.75 g reducing sugar /100g substrate was obtained from bagasse, which was the most suitable agricultural waste for this treatment.
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Tsai, Chang-Ting, i 蔡昌廷. "Comparison of the Piromyces sp. T2 xylanase production by methyltrophic yeast Pichia pastoris and Pichia methanolica". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/98578342079209544552.
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碩士國立臺灣大學
農業化學研究所
91
The methylotrophic yeasts have become one of the most potentially useful expression systems since they can be easily manipulated at the molecular genetic level; they can express proteins at a high level; they can perform the post—translational modification of higher eukaryotic proteins ; and the fermentation techniques, such as high cell density culture, have been well established. In this study, two expression systems, Pichia pastoris and P. methanolica, were developed for the production of recombinant xylanase isolated from rumen fungi Piromyces sp. T2. Recombinant xylanase were produced in flasks and fermentors to investigate the differences between these two systems. In the flask scale, P. pastoris and P. methanolica cultured by complex medium produced higher xylanase activity than those using the synthetic medium. Xylanase activity was enhanced if the cell-free suspension was replaced with fresh medium before methanol induction. In general, P. methanolica produced higher xylanase activity than P. pastoris in both flask and fermentor scale. Deletion of the six histidine tag at C-terminal of recombinant xylanase expressed in P. methanolica resulted in higher enzyme activity. In fermentor scale, no significant difference in xylanase activity was found between His-tag positive and negative strains. There were less extracellular non-target proteins in P. pastoris culture supernatant compared to those in P. methanolica, and consequently it led to easy purification and characterization of xylanase. Amongst all the tested strains and culture as well as induction conditions, cultivation of P. methanolica in the fermentor using synthetic medium, followed by the methanol induction at 3.6 ml/h without medium replacement could achieve the highest xylanase activity. The xylanase activity was 3151 U/ml after 168 hr of induction and it could reach 5202 U/ml after 216 hr of induction.
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Singh, Nashveer. "Influence of fungal diversity and production of cellulolytic enzymes on decay of stored bagasse". Diss., 2008. http://hdl.handle.net/2263/27952.
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Bagasse is the fibrous derivative of sugar cane, that is grown on a commercial scale in many tropical and sub-tropical countries, where ideal climatic conditions are experienced. The seasonality of sugar cane presents storage problems for bagasse, since this lignocellulosic material is susceptible to degradation by a diverse range of microorganisms, mainly fungi. The decay that is brought about contributes largely to the losses of fibre in a bagasse pile. The surrounding microclimate, and conditions within the pile, needs to be carefully monitored in order to understand the factors that support the fungal populations and biochemical activity. The microclimate at the surface and inside the bagasse pile at a paper mill in Stanger (South Africa) was carefully monitored over a one-year storage period. Significant changes were noted in temperature, pH and moisture content, between the surface and the inside of the pile, as the pile aged. The data were compared to established parameters for bagasse preservation, and it was found that the temperature was lower than expected, thus promoting fungal growth. The pH was much higher (promoting bacteria and actinomycetes) and the moisture content was too low to produce anaerobic conditions. The environmental conditions in the bagasse pile at Stanger, therefore, promoted the proliferation of microbes, and consequently decay. Fungi that were present in the pile, were enumerated in order to investigate the diversity and fungal succession. There was a wider variety of species and higher numbers of fungi at the surface than inside the bagasse pile and the Shannon and Berger-Parker diversity confirmed these observations. Sorensons measure also showed that the types of fungal communities at the surface and inside the pile only started becoming similar toward the latter part of storage. When compared to models for abundance of species, conditions on the surface of the pile allowed maximum niche occupation at the beginning of storage, followed by the establishment of a mature community. The inside of the pile displayed minimal niche pre-emption followed by a state where most fungal species shared the domain. This study indicated that, as the storage time increased, the microbial communities became better established. Bagasse is rich in holocellulose, the basic raw material used for paper-making. Since there were many species of holocellulolytic fungi found growing on the surface and the inside of the bagasse pile, the activity of cellulases and xylanases were determined. These enzymes were found to be active at the surface and inside the pile. However, higher activities of both enzymes were noted inside the bagasse pile than on the surface. The higher levels of activity inside the pile, despite lower fungal numbers, suggested that fungal counts were not a clear indication of biomass or biochemical activity. It appeared that the environment on the inside of the bagasse pile promoted the establishment of specific fungal populations that bring about a high degree of degradation to fibre inside the bagasse pile.Dissertation (MSc)--University of Pretoria, 2009.
Microbiology and Plant Pathology
unrestricted
33
Chen, Yih-Chung, i 陳義強. "Effects of Various Carbon Source and Their Addition Modes on the Xylanase Production of Trichoderma longibrachiatum 185". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/85552800727004251263.
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碩士國立中興大學
食品科學系
86
Hemicellulose is the second most abundant biomass to cellulose that is available in nature, and consists largely of xylan. Xylan remains to be a under-utilized resource until now. The objectives of this study are to determine the effects of adding some non-xylan compounds such as avicel, cellulose, lactose and sorbose, in alone or combined, to a medium with or without oat spelt xylan on the production of xylanase by T. longibrachiatum 185. In addition, xylanase induction by T. longibrachiatum 185 grown on the medium containing the extracted hemicellulose from agricultural wastes was also studued. The addition of avicel 、cellulose、lactose or sorbose (1％) to the medium containing 0.5％ oat spelt xylan gave maximum xylanase and CMCase production when these non-xylan compounds were added at the day0 or day 1 of cultivation. Intermittent feeding of the sorbose(％ each) every 24 hr up to 2 days or 3 days to the culture broth of T. longibrachiatum 185 led to the enhanced production of xylanase and to 38％ and 58％, respectively. Presence of surfactants such as Tween 80 or sorbitan at a concentration of 0.2％ stimulated xylanase production of T. longibrachiatum. Two-stage cultivation method the cells were initially cultivated in the presence of either one non-xylan substance alone, followed by transferring them to the other xylan-based medium enhanced production of xylanase, but the production of cellulase was inhibited. Replacement of oat spelt xylan in the Mandels-Reese medium by combinations of non-xylan compounds( either two from avicel, sorbose , lactose or cellulose) improve the yield of xylanase or CMCase, especially for the combination of 0.5％ cellulose and 0.5％ lactose.Similarly, combinations of non-xylan compounds(either three from avicel, sorbose or cellulose) also had stimulating effects. The combination of 0.8％ sorbose、0.1％avicel and 0.1％cellulose offered the best result for the strain to produce the highest amount of xylanase. Of hemicellulosic wastes tested, pulp, wood chip and water bamboo husk acted as the best carbon source for T. longibrachiatum to produce the highest amount of xylanase, and CMCase too.
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Chi, Da-Jiun, i 齊大鈞. "Fermentation of plant debris for lactic acid production by xylanase and cellulase genes transformed lactic acid bacteria". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/90778248527681134389.
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碩士國立屏東科技大學
生物科技研究所
97
Lactic acid is one of widely used organic acids. The worldwide demand for lactic acid was estimated to be 130,000 to 150,000 tones per year. For the development of bioresource, it would be an important way to produce lactic acid by using recyclable bioresources as material. In this study, the lignocellulosic materials including xylan and cellulose were used in lactic acid fermentation of xylanase and cellulase gene transformed lactic acid bacteria, respectively. The xylanase gene and cellulase gene were respectively introduced to lactic acid bacteria and obtained their transformants, Lactococcus lactis R8, Lactobacillus brevis R8 and Lb. plantarum CD. The xylanolytic or cellulolytic activity of transformants were confirmed by Congo red staining.L. lactis R8 and Lb. brevis R8 were able to grow in the medium using oat spelts xylan as sole carbon source, the xylose and the activities of xylanase and β-xylosidase would be detected in the broth, and the cell density were also much higher than wild type under the same condition. The above indicate that xylanase gene would be helpful for lactic acid bacteria to the utilize of xylan. Lb. brevis R8 could utilized xylose to produce 0.71 g/L lactic acid, but L. lactis R8 could not able to utilize xylose to produce lactic acid. The cell density of Lb. brevis R8 was similar to wild type strains in the condition when they were grown in the broth with corn cobs as sole carbon source, and the above indicate that Lb. brevis R8 could not use corn cob to produce lactic acid because the xylanase is not effective. Lb. plantarum CD was grown in the medium with glucose or cellobiose, and the ability of the transformants for metabolizing glucose or cellobiose to produce lactic acid was lower than wild type strains. Moreover, Lb. plantarum CD was able to grow in the medium containing carboxymethylcellulose and sugarcane bagasse. The transformant could secrete cellulase (CelD) with low activity degrading carboxymethylcellulose and sugarcane bagasse to reducing sugar. However, the biomass of transformants was higher, but could not produce lactic acid by using cellooligosaccharides as their carbon source.
35
Tan-Kuei, Chen, i 陳丹桂. "Production of xylanase by Aspergillus niger NCH-3 and its application on the preparation of the xylooligosaccharides". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/11476605091762598482.
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碩士國立中興大學
食品科學系
91
Hemicelluloses, which comprise mainly xylans, are abundant biomass resources in the nature. However, xylans remain to be a less utilized resource. Xylanase production from a fungal isolate, Aspergillus niger NCH-3 was used in this study. The objectives of this work were to determine the optimum pH and agitation rate for cultivation of cells using a 5 L bench-top bioreactor. In addition, some catalytic properties of Asp. niger NCH-3 xylanase using coba husk hemicellulose as substrate, and separation of the xylooligosaccharides by activated charcoal were also studied. Asp. niger NCH-3 was cultivated in a medium containing 1% coba husk hemicellulose, 1% corn steep liquor, and 0.38% KNO3 at 35℃ for 5 days. The maximum xylanase activity with 28.56 U/ml was obtained at pH 6.0 with 170~200 rpm agitation rate, and aerated at 1.0 vvm. Crude or ammonium sulfate precipitation-purified xylanase were chemically modified by different chemical reagents. The tryptophan, histidine and arginine residues in xylanase molecule was inactivated by some specific reagents. This indicated that tryptophan, histidine and arginine residues were involved in the active site or substrate binding site of the enzyme. Degree of hydrolysis of coba husk hemicellulose by the xylanase from varied slightly with different pH values, the pH values ranged from 4.0 to 5.0 for optimum hydrolysis condition. Presence of 2.5 g/L of nonionic surfactant Tween 20 increased hydrolysis ability of xylanase. Combination of activated charcoal-celite (2：1, w/w) was chosen for adsorption and separation of xylooligosaccharides from hydrolysates of coba husk hemicellulose, and the continuous mode was superior to batch mode in the elution of sugars adsorbed. Up to 90.36% of xylobiose could be recovered from the absorbed sugars by using 5% alcohol as an eluant.
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Lin, Cheng-yan, i 林正言. "Production of recombinant xylanase from Pichia pastoris X-33 using methanol feeding to control at various dissolved oxygen". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/06027497366769547288.
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碩士大同大學
生物工程學系(所)
102
Xylanase and β-glucanase have been used as feed additives for a long time and their ability to improve the feed conversion ratio and weight gain of pigs and poultry. It is widely assumed that the ability of xylanase and β-glucanase to degrade plant cell walls leads to release of nutrients from grain endosperm and aleurone layer cells. This mechanism can also be regarded as important for improving the feed energy value. A recombinant Pichia pastoris X33 with xylanase gene was employed in xylanase production. The strain was cultured using glucose as carbon source to a cell density of OD600nm 400 or a wet cell weight of 490 g/L in a 50 L fermenter, and then followed by inducing of xylanase production using methanol. Methanol performs as a carbon source and an inducer. Three fixed dissolved oxygen levels (DO 40%、DO 25%、DO 10%) were controlled by methanol feeding rates under a fixed agitation rpm, aeration rate, fermenter pressure and temperature. It is noted that the more methanol feeding rate gave the lower dissolved oxygen during the inducing process. The cell density, broth protein, xylanase activity, and the residual methanol concentration were recorded under the three different dissolved oxygen level of operation. The most xylanase activity of 44810 (U/mL) and total protein of 16850 (μg/mL) were achieved at the dissolved oxygen of 25% and the residual methanol was 0.35% at 89 h after inducing process. This probably the optimum conditions for the xylanase production using the recombinant Pichia pastoris X33.
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Chen, Ting-Wen, i 陳婷玟. "Production of Trichoderma longibrachiatum 185 xylanase by coba husk hemucellulose and its application of preparation of the xylooligosaccharides". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/51808471192810357972.
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碩士國立中興大學
食品科學系
89
Hemicellulose, which consists mainly of xylan, is the second most abundant biomass to cellulose in nature. In this study, a potent xylanase-producing strain, Trichoderma longibrachiatum 185, was used to study the medium composition and growth condition for optimal xylanase production in a 5L bench-top fermentor, enzyme properties and the preparation of xylooligosaccharides. The optimal conditions of extracting of hemicellulose from coba husk by NaOH were that using 12 % NaOH at 65℃ for 5 hours or that at 45℃ for 24 hours. Both yield were about 19.7 and 19.0 %, respectively. The better medium composition for xylanase production from T. longibrachiatum 185 were determined as follows: coba husk hemicellulose, 0.025%；corn steep liquor, 1.0%；KH2PO4, 0.2 %；CaCl2, 0.03 %；MgSO4∙7H2O, 0.03 %；Tween 80, 0.2 %；FeSO4∙7H2O, 0.0005 %；MnSO4∙H2O, 0.00016 %；ZnSO4∙7H2O, 0.0014 %；and CoCl2, 0.0002 %. For cultivation condition, pH 6.0, cultivated at 35℃, agitation rate at 130 rpm, and aeration rate at 1.0 vvm were found to be good to enzyme production. A maximum xylanase activity at 21.6 U/ml was obtained after 3 days of incubation under the above conditions. This was 1.6-times than that obtained previously by using oat spelt xylan as the carbon source and a combined nitrogen source. The optimal temperature and pH for the UF-partially purified xylanase of T. longibrachiatum 185 were 55℃ and 6.0, respectively. The major hydrolysis products of either coba husk hemicellulose or oat spelt xylan by the UF- or UF-ammonium sulfate precipitation partially purified xylanase after 24 hours depended upon the ratio of substrate to the amount of enzyme. Xylobiose and xylotriose were the major ones when the amount of xylanase was low, while xylose became apparent if higher amount of enzyme was used. The degree of hydrolysis of coba husk hemicellulose can up to the maximum when the concentration of substrate was 5%, the concentration ratio of enzyme to substrate was 208U/g and the xylanase activity was 20.5 U/ml.
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Almeida, Dulce. "Improved extraction of arabinoxylans from rye bran and production of health beneficial oligosaccharides". Master's thesis, 2011. http://hdl.handle.net/10400.1/3116.
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Dissertação de mest., Engenharia Biológica, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011The purpose of this work is to investigate and improve different technical aspects in the extraction of soluble dietary fibres, mostly AX, from rye bran and to characterize the fibres throughout the process, as well as perform enzymatic hydrolysis of arabinoxylans, producing health promoting oligosaccharides: Xylan-oligosaccharides and arabinoxylan-oligosaccharides. These hydrolysis products may serve as candidate supplements in food and feed industry because of their prebiotic proprieties. They can act as substrates which selectively stimulate the growth of probiotic bacteria that produce metabolic active compounds which can contribute, for instance, to lowering risk of colon cancer incidence, decrease cholesterol absorption and might have a positive influence on type II diabetes and obesity. The work included several enzymatic steps, using alpha-amylases, proteases and xylanses as well as extraction with steam, separation steps and purification using solvent precipitation, dialysis and freeze drying. Different analytical techniques were used to follow the enzymatic steps and to characterize the carbohydrates, including an OPA-based spectrophotometrical method to study the protein hydrolysis, acid hydrolysis in combination with High Performance Anion Exchange Chromatography with Pulsed Ampherometric Detection (HPAEC-PAD) and size-exclusion chromatography (SEC) to study the carbohydrates. As main results, regarding the extraction final product, a visible improvement in is physical appearance is achieved, as well as a significant improvement in its content in arabinoxylans which increases from 37.57% (using the previous method) up to 60.45%. Regarding the arabinoxylan / glucose ratio, it also improved from 1,84 up to a maximum of 10.02. The objective of this work was achieved with success as a significant improvement on the product composition and characteristics was achieved as well as the heath beneficial oligosaccharides were obtained, therefore, this work result on a small but good contribution for the project of my colleagues in Lund University.
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Amorim, Cláudia Catarina Oliveira. "Development of a bioprocess for the production of xylooligosaccharides". Doctoral thesis, 2019. http://hdl.handle.net/1822/60591.
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Tese de Doutoramento em BioengenhariaThe demand of prebiotic ingredients, such as xylooligosaccharides (XOS), has been growing over the years as consumers pay more attention to their health and well-being. XOS are considered emergent and competitively priced prebiotics, presenting high potential as food ingredients. As a result, the industry is focused on developing new approaches to improve production efficiency that can meet the increasing demand while reducing costs. Motivated by the industry needs, the main purpose of this thesis was to develop an integrated bioprocess, based on one-step fermentation, for the production of prebiotic XOS, towards the simplification and cost reduction of the process. The one-step fermentation of 13 agro-residues was performed using two Trichoderma species. The most promising results were found for T. reesei using brewers’ spent grain (BSG) as substrate. BSG is an inexpensive and abundant brewery agro-industrial residue that was herein proven interesting for the production of prebiotic arabino-xylooligosaccharides (AXOS). Under optimal conditions (3 days, pH 7.0, 30°C and 20 g/L of BSG), a production yield of 38.3 ± 1.8 mg/g (xylose equivalents/g of BSG) was achieved. AXOS with degree of polymerization (DP) from 2 to 5 were obtained. The onestep fermentation using T. reesei was compared with the application of a commercial xylanase from T. longibrachiatum. The first revealed to be a more attractive and low-cost strategy to hydrolyze sterilized raw BSG (without conventional pretreatment) and produce AXOS. In order to reduce the production time obtained with T. reesei (3 days), the Bacillus subtilis 3610 wild type (wt) was successfully used, for the first time, to produce AXOS through direct fermentation of BSG, reducing the production time to 12 h. Genetic engineering was used to further optimize the microorganism performance, by cloning the T. reesei xylanase gene coupled with a secretion tag into the B. subtilis chromosome (B. subtilis 3610 clone 2). After optimization by Box-Behnken experimental design, AXOS with a DP ranging from 2 to 6 were obtained at 12 h of fermentation with B. subtilis 3610 clone 2, using 20 g/L of BSG, at pH 7.0 and 45°C. The maximum production yield was 54.2 ± 1.1 mg/g (xylose equivalents/g of BSG), representing an increase of 33% comparing to the wt, and 29% comparing to the T. reesei. B. subtilis 3610 clone 2 was also selected for downscale production of XOS by direct fermentation of commercial beechwood xylan. The use of a commercial substrate allowed to better evaluate strategies to overcome common process limitations associated to the use of agro-residues as substrates, namely biomass measurement, mass transfer issues and substrate inhibition. The maximum production yield, 306 ± 4 mg/g (XOS/xylan), was achieved after 8 h of fermentation operating under one-time impulse fed-batch regimen. The optimal conditions found were pH 6.0 and 42.5°C, using 2.5 g/L of initial concentration of xylan increased up to 5.0 g/L at 3 h. A mixture of XOS with a DP ranging from 4 to 6 was obtained, presenting high stability after a static in vitro digestion (98.5 ± 0.2)%. Operating under fed-batch mode allowed to minimize the effect of substrate inhibition, which led to a great increase of the production yield. In vitro studies using human fecal inocula of two healthy donors were performed to evaluate and compare the potential prebiotic effect of commercial lactulose and the XOS herein produced through direct fermentation of beechwood xylan by B. subtilis clone 2. For both substrates, acetate was the main short-chain fatty acid (SCFA) produced during fermentation at 48 h. Lactulose led to the highest production of lactate, while XOS led to the maximum production of butyrate (9.0 ± 0.6 mM for donor 1 samples, and 10.5 ± 0.8 mM for donor 2 samples). The addition of XOS also resulted in the largest production of CO2. The significant increase in the production of SCFAs and CO2, added to the reduction of pH and ammonia concentration suggest that the XOS herein obtained hold potential functional properties for human health. The results gathered in this thesis are very promising, specially from the industrial perspective, providing important insights for the development of new integrated strategies for XOS production from agro-residues.
A procura de ingredientes prebióticos, como os xiloligossacarídeos (XOS), tem crescido ao longo dos anos, à medida que os consumidores prestam mais atenção à sua saúde e bem-estar. Os XOS são considerados prebióticos emergentes e com preços competitivos, apresentando alto potencial como ingredientes alimentares. Consequentemente, a indústria está focada no desenvolvimento de novas abordagens para melhorar a eficiência da produção, para reduzir custos e atender à crescente procura. Motivada pelas necessidades da indústria, o objetivo principal desta tese foi desenvolver um bioprocesso integrado, baseado numa única fermentação para a produção de XOS, visando a simplificação e redução de custos do processo. A fermentação direta de 13 agro-resíduos foi realizada utilizando duas espécies Trichoderma. Os resultados mais promissores foram observados para o T. reesei, usando dreche (BSG) como substrato. A dreche é um resíduo agro-industrial barato e abundante, proveniente da indústria cervejeira que provou ser interessante para a produção de arabino-xilooligossacarídeos (AXOS). Sob condições ótimas (3 dias, pH 7,0, 30°C e 20 g/L de BSG), obteve-se um rendimento de produção de 38,3 ± 1,8 mg/g (equivalentes de xilose/g de BSG). Os AXOS obtidos apresentaram um grau de polimerização (DP) entre 2 e 5. A produção de AXOS através de fermentação com T. reesei foi comparada com a aplicação de uma xilanase comercial de T. longibrachiatum. A fermentação revelou ser uma estratégia mais atrativa e de baixo custo para hidrolisar a dreche esterilizada por autoclave (sem pré-tratamento convencional) e para produzir AXOS. De modo a reduzir o tempo de produção obtido com o T. reesei (3 dias), estudou-se, pela primeira vez, a produção AXOS através de fermentação direta da dreche usando o Bacillus subtilis 3610 wild type (wt), o que levou à redução do tempo de produção para 12 h. Recorrendo a engenharia genética, o desempenho do microrganismo foi otimizado, através da integração no seu cromossoma do gene da xilanase do T. reesei acoplado a um tag de secreção (B. subtilis 3610 clone 2). Após otimização do processo com recurso a um desenho experimental de Box-Behnken, foram produzidos AXOS com DP de 2 a 6 após 12 h de fermentação com o B. subtilis 3610 clone 2, utilizando 20 g/L de BSG, pH 7,0 e 45°C. O rendimento máximo de produção foi de 54,2 ± 1,1 mg/g (equivalentes de xilose/g de BSG), representando um aumento de 33% em relação à wt e 29% em relação ao T. reesei. O B. subtilis 3610 clone 2 foi também selecionado para a produção em menor escala de XOS através da fermentação direta de xilano comercial obtido de madeira de faia. O uso de um substrato comercial permitiu uma melhor avaliação das estratégias necessárias para superar as limitações que são geralmente associadas ao uso de agro-resíduos, nomeadamente, a quantificação da biomassa, os problemas de transferência de massa e a inibição pelo substrato. O rendimento máximo de produção, 306 ± 4 mg/g (XOS/xilano), foi observado após 8 h de fermentação, operando sob regime de fed-batch com um impulso. As condições ótimas encontradas foram pH 6,0 e 42,5°C, utilizando 2,5 g/L de concentração inicial de xilano aumentada para 5,0 g/L às 3 h. Nestas condições obteve-se uma mistura de XOS com um DP entre 4 e 6, que apresentou elevada estabilidade (98,5 ± 0,2%) após ter sido sujeita a um processo de digestão estática in vitro. A produção em modo fed-batch permitiu ainda minimizar o efeito da inibição do substrato, o que levou a um aumento significativo do rendimento de produção. Foram realizados estudos in vitro com inóculos fecais humanos de dois dadores saudáveis para avaliar e comparar o potencial efeito prebiótico da lactulose comercial e da mistura de XOS produzida por fermentação direta de xilano de madeira de faia usando o B. subtilis clone 2. Para ambos os substratos, o acetato foi o principal ácido gordo de cadeia curta (AGCC) produzido após 48 h de fermentação. A lactulose apresentou a produção mais elevada de lactato, enquanto que os XOS apresentaram a produção mais elevada de butirato (9,0 ± 0,6 mM para o doador 1 e 10,5 ± 0,8 mM para o doador 2). A adição de XOS ao meio de cultura também resultou numa produção mais elevada de CO2. O aumento significativo na produção de AGCCs e CO2, bem como a redução do pH e da concentração de amónia, sugere que os XOS produzidos neste trabalho podem apresentar propriedades funcionais importantes para a saúde humana. Os resultados obtidos nesta tese são bastante promissores, especialmente do ponto de vista industrial, apresentando-se informação relevante para o desenvolvimento de novas estratégias integradas para a produção de XOS a partir de agro-resíduos.
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Chen, Man-Jhen, i 陳蔓甄. "Study on solid-state cultivation conditions for mannanase and xylanase production by Aureobasidium pullulans NCH-218 using soybean okara as a major substrate". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/28330228084177058330.
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41
Shih-Hao, Tseng, i 曾士豪. "Production of xylanase by Aspergillus niger NCH-3 with coba husk hemicellulose ( in stirred tank ) and its application on the preparation of the xylooligoaccharides". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/32608373258569200693.
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碩士國立中興大學
食品科學系
90
The xylanase production from a fungal isolate, Aspergillus niger NCH-3, by using the hemicellulose extracting from a domestic agricultural waste coba husk as carbon source was studied. These included determinations of optimal condition for extracting from hemicellulose, and the medium composition for optimal xylanase production, characterization of enzyme properties, and the hydrolysis profiles of xylanase using coba husk hemicellulose and/or oat spelt xylan as enzymatic substrates. The optimal conditions for extracting hemicellulose from coba husk by NaOH were that using 15% NaOH at 60℃for 5 hr or that at 40℃for 30hr. The yields were about 23.7 and 24.0%, respectively；however, the highest yield, 25.2%, was obtained at 60℃for 30 hr. The better medium composition for Aspergillus niger NCH-3 xylanase production were determined by using a 5 L bench-top fermentor as follows：coba husk hemicellulose, 1.0 %；corn steep liquor, 1.0 %；KNO3, 0.38 %；KH2PO4, 0.02 %；CaCl2, 0.0002 %；Tween 80, 0.2 %；MgSO4．7H2O, 0.03 %；FeSO4． 7H2O, 0.0005 %； ZnSO4． 7H2O, 0.0014 %；MnSO4．H2O, 0.00016 %, pH 8.0. The strain was cultivated at 35℃, with agitation rate at 150 rpm, and aerated at 1.0 vvm for 5 days. The final xylanase activity obtained was at 32.4 U/ml. The optimal pH for the UF and ammonium sulfate precipitation -purified xylanase was pH 5.0, however, the enzyme remained stable at pH ranging values from pH 4.0 to 7.0. Both thermal stability and optimal temperature for partially purified xylanase were at 50℃. The enzyme also showed high specificity on xylans composed of xylose residues. The types of major hydrolysis products of either coba husk hemicellulose or oat spelt xylan catalyzed by the UF- or UF-ammonium sulfate precipitation-purified xylanase after 24 hours depended upon the ratio of substrate to the amount of enzyme used；however, xylose and xylobiose were the major ones.
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Amerah, Ahmed M. "Feed particle size, whole wheat inclusion and xylanase supplementation in broiler diets : influence on the performance, digesta characteristics and digestive tract development : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Poultry Nutrition at Massey University, Palmerston North, New Zealand". 2008. http://hdl.handle.net/10179/1586.
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The first three experiments of this thesis examined the effects of particle size reduction of grains in relation to feed form (mash vs. pellet), grain type (wheat vs. maize) and xylanase supplementation on broiler performance, energy utilisation, digestive tract development and digesta parameters. The fourth experiment examined the interaction between wheat hardness and xylanase supplementation. The effects of insoluble fibre source and whole wheat inclusion were studied in the fifth experiment. In the first experiment (Chapter 4), pelleting reduced nitrogen-corrected apparent metabolisable energy (AMEn), but broiler performance was superior in birds fed pelleted wheat-based diets compared to those fed mash diets. Feed form had a greater effect on various measured parameters than did particle size. Pelleting evened out differences in particle size distribution between treatments and, as a result, wheat particle size had no effect on the performance of broilers fed pelleted diets. In contrast, the second experiment (Chapter 5) showed that differences in particle size distribution persisted between diets after pelleting and, as a result, coarse grinding of wheat or maize improved broiler performance compared to those fed diets based on fine particles. These results may be related, in part, to changes in size distribution following pelleting. In mash diets, inconsistency in performance reponses were found. In the first experiment (Chapter 4), coarse grinding of wheat improved weight gain and feed per gain compared to medium grinding. In the third experiment (Chapter 6), however, grinding particle size had no influence on broiler performance. The observed discrepancy suggests involvement of other factors such as wheat cultivar and grain hardness. Data reported in Chapter 6 showed that xylanase supplementation improved feed per gain of birds fed the coarse particle size diet, but had no effect on those fed the medium particle size diet. In Chapter 7, there was a significant interaction between wheat hardness and xylanase supplementation due to the improved feed per gain and AMEn of birds maintained on hard wheat-based diet, while there was no effect of xylanase on sort wheat-based diet. These findings suggest that the efficiency of exogenous enzymes is influenced by both particle size and wheat hardness. Data reported in Chapter 7 showed that inclusion of soft or hard whole wheat pre-pelleting produced different particle size distributions in the pelleted diets. This suggested that hardness of the grain must be considered when choosing whole wheat for inclusion in broiler diets. Data on the effect of feed particle size on its subsequent distribution in poultry digesta are scanty. Results reported in Chapters 4 and 5 showed that there was no effect of feed particle size within feed form on duodenal digesta particle size. On the other hand, particle size of duodenal digesta was influenced by feed form (mash vs. pellet). Wheat hardness was also found to influence the particle size of proximal (duodenum and jejunum) intestinal digesta (Chapter 7). These results indicated that the gizzard does not uniformly reduce the size of all particles. However, the gizzard appears highly efficient in grinding large particles, although some large particles escape the grinding. The final experiment demonstrated that the effects of insoluble fibre on digestive tract development and broiler performance differed depending on the fibre source. Wood shavings, a source of coarse insoluble fibre, increased relative gizzard size and improved corrected feed per gain and ileal starch digestibility. In contrast, cellulose, a source of fine insoluble fibre, had no influence on these parameters. In conclusion, dietary manipulations, which stimulated gizzard development, positively influenced broiler performance and starch digestibility. The findings of this thesis suggest that energy savings during feed processing could be achieved by coarse grinding of grains with no adverse effect on broiler performance and that cereals used in broiler diets can be ground more coarsely than the current practice. Wheat hardness appears to be an important criterion to consider when choosing a cultivar for whole wheat inclusion in broiler diets. Another major finding was that the effectiveness of exogenous xylanase in wheat-based diets could be improved by considering factors such as particle size and wheat hardness.
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Pillai, Santhosh Kumar Kuttan. "Investigations of the bioprocess parameters for the production of hemicellulases by Thermomyces lanuginosus strains". Thesis, 2012. http://hdl.handle.net/10321/740.
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Submitted in fulfilment for the requirement of a Degree of Doctor of Technology: Biotechnology, Durban University of Technology, 2010.The aim of this study was to evaluate T. lanuginosus for the production of hemicellulases, its yield enhancement using mutagenesis and application of a selected xylanase on bagasse pupl to assess the improvement of pulp properties. The objectives were: To determine the localization of hemicellulases in T. lanuginosus strains, To develop high yielding strains of T. lanuginosus through mutagenensis, To investigate the synthesis of xylanase by T. lanuginosus MC134, To optimize the medium components and cultural conitions of T. lanuginosus MC134 strain, To study the influence of agitation and aeration on the production of xylanase by T. lanuginosus MC134 in a fermenter, To evaluate the bleach boosting abilities of T. lanuginosus xylanase on bagasse pulp, To evaluate simultaneous xylanase production and biobleaching potential of T. lanuginosus.
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Li, Heng-Yi, i 李姮誼. "Fed-Batch Production of Thermostable Recombinant Xylanases from Paenibacillus sp. isolate BL11 in Escherichia coli". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/85529358270434660029.
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碩士國立臺灣大學
森林環境暨資源學研究所
95
Xylanase have rather extensive application value on the industry, it is making syrup deckle industry, the food beverage industry, the forage industry, textile industry all has it an application. This laboratory before already there is scholar will a by from Hsinying Paper Mill of Taiwan Pulp and Paper of the BL11 of Paenibacillus campinanesis of the separation in the black liquid to gather the xylanase gene turns to go into Escherichia coli, and makes use of the lac promoter to control the performance of the gene, can effectively of expression xylanase in the host cell body. The cloned BL11 xylanase is composed of 1,131 nucleotides and can encode a protein of 41 kDa. The effects of culture variables on xylanase production by the recombinant E. coli were investigated using a controlled fed-batch fermentation system. In flask culture scale test of the item be having host category, carbon source density, organic nitrogen source category of developing medium and having no machine nitrogen source category. With E. coli BL21 (DE3) for the host be controling the condition as pH 7.0, dissolve the oxygen value control in 35%, the temperature in 37 oC, joining the 0.06 mM IPTG inducement in culture 6 h to gather xylanase after culture 30h, can reach to 2.63 g DCW/L and xylanase specific activity reach to 233.45 IU/mg. Xylotriose was the major hydrolytic product of oat spelt and birchwood xylan.
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Li, Heng-Yi. "Fed-Batch Production of Thermostable Recombinant Xylanases from Paenibacillus sp. isolate BL11 in Escherichia coli". 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2507200701495600.
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Waung, Debbie. "Optimizing Enzymatic Preparations of Mechanical Pulp Through the Characterization of New Laccases and Non-productive Interactions Between Enzymes and Lignin". Thesis, 2010. http://hdl.handle.net/1807/25508.
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The overall objective of this research is to identify and optimize enzymatic applications that have the potential to degrade middle lamella lignin, so as to decrease economic and environmental costs associated with the production of mechanical pulp. Non-productive binding of enzyme to lignin in lignocellulosic biomass reduces enzyme availability and efficiency. The elucidation of non-productive binding behavior between hydrolytic enzymes and lignocellulosic substrates could significantly improve the efficiency of corresponding industrial bioprocesses. The first part of this report presents a study that characterizes non-catalytic interactions between enzymes and fibre. The second part of this report presents the biochemical and mutational studies of a novel, small laccase SCO6712 from Streptomyces coelicolor. The findings from this research support the design, control, and optimization of enzymatic treatments of lignocellulosic fibres in the pulp and biofuel industries.