Orientador: Yong Kun Park / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-24T09:31:49Z (GMT). No. of bitstreams: 1 Contado_JoseLuis_D.pdf: 5265713 bytes, checksum: d8b1e9c15dba1c02f381597ff13b0f09 (MD5) Previous issue date: 1998 / Resumo: Frutooligossacarídeos, ou Neosugar, são oligômeros de sacarose, constituídos de uma molécula de glicose unida com 2, 3 ou 4 unidades de frutose por ligação ß-2,1, resultando em estruturas designadas como 1-kestose (GF2), nistose (GF3) e 1f-frutofuranosil nistose (GF4), respectivamente. Sabe-se que os frutooligossacarídeos existem naturalmente em muitos tipos de plantas. Podem também ser obtidos a partir de sacarose através da transfrutosilação catalisada pela enzima ß-frutofuranosidase (E.C.3.2.1.26) de microrganismos. Frutooligossacarídeos têm-se tomado de grande interesse por estimular o crescimento de bifidobactérias benéficas do trato digestivo, diminuir o teor do colesterol total e lipídeos no soro sanguíneo, reduzir a constipação intestinal, e em geral melhorar a saúde humana. Neosugar é uma mistura de frutooligossacarídeos, 1-kestose (GF2), nistose (GF3) e 1f-frutofuranosil nistose (GF4) e é comercialmente produzido a partir de sacarose usando a ß-frutofuranosidase obtida de A. niger. O objetivo deste trabalho foi induzir um mutante de Aspergillus niger, utilizando o reagente N-Metil N' -Nitro N-Nitrosoguanidina (M.N.N.G.) e raios ultravioleta (UV), que produzisse uma ß-frutofuranosidase com maior atividade de transfrutosilação para produção de frutooligossacarídeos do que a linhagem parental e comparar as características das duas enzimas. Uma linhagem mutante (nº 12) de A. niger, obtida pelo tratamento com M.N.N.G.-UV, foi selecionada por apresentar mais que o dobro da atividade ß-frutofuranosidase que a linhagem parental. Esta linhagem mutante produziu menos conídea em PDA e mostrou-se morfologicamente diferente apresentando colônias bege. A ß-frutofuranosidase extracelular da linhagem mutante foi purificada cerca de 15,8 vezes em relação a enzima bruta sendo obtido 39,2 % de rendimento. A enzima purificada apresentou atividade específica de 4,26 unidades/mg de proteína. A enzima apresentou pH e temperatura ótima de atividade na faixa de 5,5-6,0 e 50-55°C, respectivamente. A enzima mostrou-se estável na faixa de pH 5,0 a 6,0 e a temperaturas inferiores a 55°C. Os valores de km e Vmáx da ß-frutofuranosidase para sacarose foram 0,47 M e 1,02 µmol/ml/min, respectivamente. A atividade enzimática foi inibida com 1 mM de N-bromosuccinimida, ß-mercaptoetanol, HgCl2 e I2, e com 10 mM de AgNO3, após 30 minutos a 55°C. A ß-frutofuranosidase extracelular da linhagem mutante foi purificada cerca de 15,4 vezes em relação a enzima bruta sendo obtido 31,7 % de rendimento. A enzima purificada apresentou atividade específica de 1,66 unidades/mg de proteína. A enzima apresentou pH e temperatura ótima de atividade na faixa de 5,0-6,0 e 50-55°C, respectivamente. A enzima mostrou-se estável na faixa de pH 5,0 a 6,0 e a temperaturas inferiores a 55°C. Os valores de Km e Vmáx da ß-frutofuranosidase para sacarose foram 0,37 M e 1,12 µmol/ml/min, respectivamente. A atividade enzimática foi inibida com 1 mM de N-bromosuccinimida, ß-mercaptoetanol, HgCl2 e I2. e com 10 mM de AgNO3, após 30 minutos à 55°C.O maior rendimento de frutooligossacarídeos (54,41%) em relação aos açúcares totais foi obtido utilizando-se ß-frutofuranosidase e 30% substrato sacarose em tampão citrato-fosfato pH 5,5 após 6 horas de incubação a 55°C. A concentração de substrato e o tempo de incubação são importantes para obter a proporção de GF2/GF3/GF4 desejada / Abstract: Fructooligosaccharides (or Neosugar) are sucrose oligomers, which are composed of glucose attached via a ß-(2-1) linkage to 2, 3 or 4 fructose units. The resulting structures are designated as l-kestose (GF2), nystose (GF3) and lf-fructofuranosylnystose (GF4), respectively. It is known that fructooligosaccharides exist naturally in many kinds of plants. They can also be prepared from sucrose through the transfructosylating action of enzyme ß-fructofuranosidase (E.C. 3.2.1.26) obtained from microorganisms. Fructooligosaccharides have become of major interest due to their growth stimulation of beneficial bifidobacteria in the digestive tract, decrease of total cholesterol and lipid in the serum, relief of constipation, and general improvement of human health. Neosugar is a mixture of the fructooligosaccharides, l-kestose (GF2), nystose (GF3) and 1f-fructofuranosylnystose (GF4), and is commercially produced from sucrose using the enzyme ß-frutofuranosidase enzyme obtained from A. niger ATCC 20611. The objective of this work was to induce a mutant of Aspergillus niger, using M-Methyl N'-Nitro N-Nitrosoguanidine (M.N.N.G.) and ultraviolet ligth (UV) producing higher ß-fructofuranosidase activity for the production of fructooligosaccharides than the parent strain and to study the characteristics of the enzyme. A mutant strain(nº 12) of A. niger, obtained by treatment with M.N.N.G.-UV, was selected, producing 100% more ß-fructofuranosidase than the parent strain. The mutant produced less conidia on PDA and was morphologically different: brownish white colonies. The extracellular ß-fructofuranosidase of the mutant strain was purified about 15.8-fold (40.2% yield) with respect to the crude enzyme preparation, showing a specific activity of 4.26 units/mg protein. It was found that the optimum pH and temperature for activity were 5.5-6.0 and 50-55°C, respectively. The enzyme was stable from pH 5.0 to 6.0 and at temperatures below 55°C. The Km and Vmáx values of the ß-fructofuranosidase for sucrose were 0.47 M and 1.02 µmol/ml/min., respectively. The activity of the enzyme was inhibited by 1 mM by N-bromosuccinimide, ß-mercaptoethanol, HgCl2 and I2, and by 10 mM AgNO3 after 30 minutes at 55°C. The extracellular ß-fructofuranosidase parent strain was purified about 15.4-fold (38.6 % yield) with respect to the crude enzyme preparation showing a specific activity of 1.66 units/mg protein. It was found that the optimum pH and temperature for activity were 5.0-6.0 and 50-55°C, respectively. The enzyme was stable from pH 5.0 to 6.0 and at temperatures below 55°e. The enzyme was stable from pH 5.0 to 6.0 and at temperatures below 55 °e. The Km and Vmax values of the ß -fructofuranosidase for sucrose were 0.37 M and 1.12 µmol/ml/min.., respectively. The activity of the enzyme was inhibited by 1 mM by N-bromosuccinimide, ß-mercaptoethanol, HgCl2 and I2, and by 10 mM AgNO3 after 30 minutes at 55°C. Maximum conversion yeld from sacarose to fructo-oligosaccharides (54.41%) was obtained when added ß-frutofuranosidase in 30% sucrose, at 55°C and pH 5,5, for 6 hrs incubation. The production efficienceis of GF2/GF3/GF4 depending on sucrose concentration and the reaction time / Doutorado / Doutor em Ciência de Alimentos

Orientador: Ranulfo Monte Alegre / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-25T00:32:50Z (GMT). No. of bitstreams: 1 Rizzatto_MarciaLuzia_M.pdf: 2359270 bytes, checksum: 5478fd798a0355f913b6d8f29070ea82 (MD5) Previous issue date: 1999 / Resumo: No presente trabalho, estudou-se a produção e produtividade de pectinase por Penicillium italicum IZ 1584 e por Aspergillus niger NRRL 3122 através de fermentação semi-sólida de bagaço de laranja industrialmente processado, em embalagens de polipropileno. Foram feitos ensaios com bagaço de laranja lavado e não lavado. A produção de pectinases com bagaço lavado iniciou-se mais cedo, porém os valores de atividade obtidos com o bagaço não lavado foram maiores para os dois microrganismos, sendo os valores da atividade do P. italicum IZ 1584 (15,1 UIlgMFU) maiores que os do A. niger NRRL 3122 (9,56 UIlgMFU). Em ensaios utilizando bagaço de laranja lavado adicionado de açúcares sacarose, glicose ou frutose, observou-se atividade máxima no meio com sacarose (15,02 UIlgMFU), para o P. italicum IZ 1584, enquanto que os meios com glicose e frutose apresentaram valores próximos de atividade 6,88 UIlgMFU e 6,94 UI/g 1\.1FU, mas menores comparados com o meio com sacarose. O fungo A. niger NRRL 3122 produziu pouca atividade de pectinase nos meios aos quais foram adicionados os açúcares. A atividade máxima foi obtida em meio com glicose (1,98 UI/gMFU), valor próximo do meio com frutose (1,55 UIlgMFU) e o meio com sacarose foi o que apresentou o menor valor de atividade (1,1 UIlgMFU). O fungo P. italicum IZ 1584 mostrou-se mais adequado para a produção de pectinase nos meios de fermentação testados. A produção de pectinase por P. italicum IZ 1584 foi 37% maior que a produção por A. niger NRRL 3122 em bagaço não lavado, 40% em bagaço lavado, 93% em meio com sacarose, 28,8% em meio com glicose e 77,7% em meio com frutose. Em fermentação utilizando misturas de bagaço lavado e não lavado em diferentes proporções, os maiores valores de atividade de pectinase também foram obtidos com o fungo P. italicum IZ 1584. O valor máximo de atividade de pectinase obtido (20,72 UIlgMFU), foi com o meio com 75% de bagaço lavado e 25% de bagaço não lavado, sendo este valor, o maior encontrado neste trabalho / Abstract: The objective of this experimental work was to study the pectinase production and productivity by Penici/lium italicum IZ 1584 and Aspergillus niger NRRL 3122, through solid-state fermentation in a medium containing processed orange bagasse as substrate, in flexible polypropilen packs. The initial experiments studied the medium composed by washed orange bagasse and no washed bagasse as source of carbono The pectinases production with washed bagasse began earlier, however the activity values obtained with no washed bagasse were bigger for the two microorganisms 15.1 UIlgMFU and 9,56 UIlgMFU, respectively, P. italicum IZ 1584 and A. niger NRRL 3122. In the experiments using washed orange bagasse supplemented with sugars (sucrose, glucose or fiutose), a maximum activity was observed in the medium with sucrose (15.02 UIlg MFU) for the P. italicum IZ 1584, while the media with glucose or fiutose presented close values of activity of 6.88 UIlgMFU and 6.94 UIlgMFU, respectively, but they were smaller when compared with the medium with sucrose. The fungus A. niger NRRL 3122 produced small pectinase activity in the media where sugars were added. The maximum activity was obtained in the medium with glucose (1,98 UIlgMFU), with similar value for the medium with fiutose (1.55 UIlgMFU). The medium with sucrose (1.1UI1gMFU), presented the smallest activity value. The fungus P. italicum IZ 1584 showed best pectinase production in the tested fermentation media. The pectinase production by P. italicum IZ 1584 was 370,10 superior to the A. niger NRRL 3122 on no washed bagas se, 40% on washed bagasse, 93% on the medium with sucrose, 28.8% on the medium with glucose and 77% on the medium with frutose. In fermentation using mixtures of washed bagasse and no washed bagasse in different proportions, the biggest values of pectinase activity were also obtained with the fungusP. italicum IZ 1584. The maximum value ofactivity (20.72UI/gMFU) was obtained on a medium with 75% washed bagasse and 25% no washed bagasse. This value was the maximum found in this work / Mestrado / Mestre em Engenharia de Alimentos

Orientador: João Lucio de Azevedo / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-07-25T15:34:04Z (GMT). No. of bitstreams: 1 Martens_IngridSchmidt-Hebbel_D.pdf: 7343296 bytes, checksum: 4ce47b2ce62b55b5bca6954dc4e9d09c (MD5) Previous issue date: 1999 / Doutorado

Fructooligosaccharides (FOS) are short-chain fructans with a terminal glucose moiety and are found naturally in many plant species. Besides their wide use as an alternative sweetener in food and beverage industry, FOS have shown great potential as neutraceuticals against diabetes, colon cancer and bowel disease. The uses of FOS are dependent on the degree of polymerisation that they exhibit. β-fructofuranosidase (FFase) and fructosyltransferase (FTase) enzymes are capable of synthesing FOS from carbohydrate raw materials such as chicory and sugar beet. The aim of this study was to investigate the synthesis of FOS of a pre-defined chain length, from sucrose, by the enzyme FopAp; a β-fructofuranosidase from Aspergillus niger. ATCC 20611. The crude enzyme FopAp was successfully purified, with a yield of 78.20 %, by ammonium sulphate precipitation and anion exchange chromatography. Two protein fractions, named FA and FB were shown to exhibit FFase activity. SDS PAGE analysis revealed two proteins with molecular weights of 112 kDa and 78 kDa, which were identified as a FFase and a hydrolase. Temperature and pH optima of 20 ºC and 9, respectively, were observed for the transfructosylation activity in the FFase. The purified FFase exhibited a half life of 1.5 hrs under optimal conditions. Substrate kinetic studies indicated a high hydrolytic activity at low sucrose concentrations, with Vmax and Km of 1.25 μmol/ml/min and 3.28 mM, respectively. Analysis by response surface methodology identified temperature and pH to be significant factors for the production of kestose and nystose, at a 95 % level of confidence. These findings were confirmed by neural networks constructed to identify optimal conditions of FOS synthesis.FOS synthesis was found to be optimal between pH 6 and pH 9 at 25 ºC. The factor of reaction time was found to be insignificant within the selected experimental constraints, for both FOS species. The findings of this investigation are very important as the foundations of a commercially viable synthetic process for the production of FOS.

Recent data on the effect of trace elements on the production of citric acid by Aspergillus niger 72-4 suggested that at last a firm basis had been established for studies on the mechanism of production. Citric acid production is an important commercial process and most research had been directed toward obtaining high yields of the acid. The small amount of information on mechanisms is invalidated by the new knowledge of the importance of trace minerals in citric acid synthesis. The attempt at elucidating a system was approached by studying the distribution of organic phosphates in the mats and by manometric experiments. By using the Umbreit fractionation method combined with chromatographic analysis none of the phosphorylated intermediates present in the Embden-Meyerhof system could be identified. Evidence for a pentose and a ketose phosphate is presented. The manometric studies on still cultures were unsatisfactory due to a high endogenous rate and to difficulties in handling the mat. Shake cultures grown for four days and then depleted for 24 hours in the medium minus sucrose and manganese were shown to be a workable method for manometric studies. Using this method evidence for the presence of most of the enzymes required for the oxidation of the Krebs cycle intermediates is presented. A survey of the literature on cell preparations was made. Attempts to prepare active cell preparations failed since enzyme activity seems to be associated with the structural integrity of the mycelium. / Land and Food Systems, Faculty of / Graduate

Orientador : Renato Bonatelli Junior / Dissertação (mestrado) - Universidade Estadual de Campinas. Instituto de Biologia / Made available in DSpace on 2018-07-17T01:59:07Z (GMT). No. of bitstreams: 1 Vialta_Airton_M.pdf: 5894822 bytes, checksum: 4493787d6f88a9c0cd04c4bbaac32710 (MD5) Previous issue date: 1987 / Resumo: O presente trabalho teve como objetivos principais, verificar a ocorrência do ciclo parassexual em Aspergillus awamori, testar a produção de amiloglicosidase dos derivativos, mutantes e diplóides obtidos e realizar o cruzamento interespecífico com A. niger. Além desses, estudos foram desenvolvidos com a instabilidade apresentada por A. awamori.. A linhagem NRRL 3112 segrega conídios pro e forma setores espontaneamente. Este comportamento não seria o esperado para um clone e sugere a existência de heterozigose para as características estudadas, a qual poderia estar contida numa duplicação parcial ou total de genoma. Mutantes auxotróficos e morfológicos de Á. awamori foram conseguidos utilizando-se os métodos de isolamento total e de enriquecimento por filtração. Este último mostrou freqüências de isolamento 12 vezes maiores. Mutantes resistentes ao Brometo de Etídio também foram isolados, mas somente após indução com luz ultravioleta. Os mutantes foram utilizados em cruzamentos que permitiram verificar a ocorrência do ciclo parassexual. Através da análise dos segregantes, pode ser evidenciada ligação entre os genes etbl, grel bwnl; morl, arg2 e leul, mor2. O gene pabl segregou independentemente e, assim, foi possível sugerir 4 como o numero mínimo de grupos de ligação nessa espécie. Entre os critérios não geneticos utilizados na caracterização, o diâmetro de conídios e o tratamento com Benlate mostraram-se eficientes para separar haplóides de diplóides. O método de extração e quantificação de DNA por núcleo também foi adequado para esse fim. Com relação ã enzima, o primeiro passo foi averiguar se o método empregado estava medindo a atividade da amiloglicosidase, fato que foi confirmado fazendo o teste com o inibidor e a dextrina limite. Foi constatada uma relação inversamente proporcional entre a porcentagem de segregação de conídios pro e a produção de amiloglicosidase. Só foi possível obter o cruzamento entre A. awamori e Á. niger através de fu são de protoplastos. A freqüência de formação de colônias prototróficas foi relativamente baixa, situando-se na faixa de 0,6%, possivelmente devido ao pequeno número de protoplastos utilizados para a fusão e a um provável efeito tóxico diferencial do agente fusogênico utilizado. As colônias prototróficas isoladas inicialmente puderam ser classificadas como heterocarióticas. A partir destas, o produto de fusão híbrido foi obtido na forma de setores que exibiam complementação entre as marcas genéticas das parentais. Através da análise do híbrido, pode ser evidenciada ligação entre os genes nicl, 0lv2, bwnl, amy, pro. Houve distribuição ao acaso dos grupos de ligação, semelhante ao esperado para um diplóide intra - específico sugerindo alto grau de homologia cromossômica entre as duas espécies. Os mesmos critérios de caracterização utilizados com sucesso para separar linhagens haplóides de diplóides. nos cruzamentos intra-específicos foram adotados e também nesse caso mostraram resultados satisfatórios / Abstract: The present work with Aspergillus was done aiming to study the following: 1- Occurrence of the parasexual cycle;2- Occurrence of interspecific hybridization with A. niger.3- Amyloglucosidase production of the parental and derived strains, including auxotrophic mutants, diploids and the interspecific hybrid. During the first stage of the work, it was observed that the NRRL 3112 strain of A. awamori is unstable because it spontaneously segregates pro conidia (deficient for proline synthesis) and produces sectors. The last characteristic is also observed in pro derivatives and it was supposed that it is independent from pro conidia segregation. These characteristics are not expected from a clone and together with other evidences (Benlate segregation, differential susceptibility to acetone, variation in number of nuclei per conidia and conidial diameter), it was suggested that there is a partial or total duplication of the genome. Auxotrophic and morphological mutants of A. awamori were induced by ultraviolet light and selected by using total isolation and filtration enrichment methods. An increase of 12 times in the mutant frequency was observed when the last method was employed. Ethidium bromide resistant mutants were also isolated only after ultraviolet induction. Diploid strains were readily obtained and could easily be' separated from haploid strains by conidia diameter, Benlate segregation and nuclear DNA content. Segregation analysis indicated linkage between etb1 gre1 bwn1, mor1, arg1 and leu1, mor2. Because pab1 marker segregated independently from all others it was suggested at least 4 linkage groups for A. awamori. Only heterokaryotic colonies were detected when A. awamori and A. niger protoplasts were fused and plated in selective medium. The low frequency (0,6%) and the heterokaryotic nature of the colonies could probably be attributed to: 1) low protoplasts number and 2) toxic effect to the fusogenic agent to A. niger protoplasts. Hybrid colonies were isolated after several transfers in selective medium. The hybrid nature of these colonies was established by the same criteria used in the intraspecies crossing. Segregation analysis indicated a high level of chromosomal homology between the 2 species and it was possible to suggest linkage between nic1 olv2 genes of niger and bwn, amy, pro of awamori. As it was evident from the use of limit dextrin and a specific inhibitor. glucoamylase is the main enzyme activity detected by the usual assay procedure. It has also been detected that high. frequency of pro conidia in A. awamori is correlated with the low level of enzyme production / Mestrado / Mestre em Genetica

No description available.

Submitted in complete fulfillment for the Degree of Master of Science (Applied Science), Durban University of Technology, Durban, South Africa, 2016. / β-xylosidases catalyse the hydrolyses of xylooligosaccharides into the monosaccharide sugar, xylose. In this study we report the production of xylose under different conditions in Pichia pastoris and Saccharomyces. cerevisiae, and its conversion to bioethanol using Pichia stipitis. The aim of this study was to change the characteristics of the A. niger 90196 β-xylosidase through random mutagenesis and increase expression under the control of different promoter systems in yeasts P. pastoris and S. cerevisiae. The recombinant library created through random mutagenesis was screened for changes in activity and subsequently pH and temperature stability. One variant showed an increase in enzyme expression, thermostability, and a change in amino acid sequence at residue 226. The enzyme was then cloned, expressed and characterized in P. pastoris GS115 and S. cerevisiae. β-xylosidase was constitutively expressed in P. pastoris using the GAP promoter and the inducible AOX promoter. In S. cerevisiae the enzyme was expressed using the constitutive PGK promoter and inducible ADH2 promoter systems. Enzyme functionality with the different expression systems was compared in both hosts. The GAP system was identified as the highest-producing system in P. pastoris, yielding 70 U/ml after 72 hours, followed by the PGK system in S. cerevisiae, with 8 U/ml. A 12% SDS-PAGE gel revealed a major protein band with an estimated molecular mass of 120 kDA, and the zymogram analysis revealed that this band is a fluorescent band under UV illumination, indicating enzyme activity. Stability characteristics was determined by expressing the enzyme at different pH and temperatures. Under the control of the GAP promoter in P. pastoris, enzyme activity peaked at pH4 while retaining 80% activity between pH 3 – 5. Highest activity of 70 U/ml xylosidase was recorded at 60ºC. Due to the high enzyme production in P. pastoris, the co-expression of this enzyme with a fungal xylanase was evaluated. The xylanase gene from Thermomyces lanuginosus was cloned with the GAP promoter system and expressed together with the β-xylosidase recombinant in P. pastoris. Enzyme activities of the co-expressed recombinant revealed a decrease in enzyme activity levels. The co-expressed xylanase production decreased by 26% from 136 U/ml to 100 U/ml while the xylosidase expression decreased 86% from 70 U/ml to 10 U/ml. The xylose produced from the hydrolysis of birchwood xylan was quantified by HPLC. The monosaccharide sugar was used in a separate saccharification and fermentation strategy by P. stipitis to produce bioethanol, quantified by gas chromatography. Bioethanol production peaked at 72 h producing 0.7% bioethanol from 10 g/l xylose. In conclusion a β-xylosidase from Aspergillus niger was successfully expressed in P. pastoris and was found to express large quantities of xylosidase, that has not been achieved in any prior research to date. The enzyme was also successfully co-expressed with a Thermomyces xylanase and is now capable of bioethanol production through xylan hydrolysis. This highlights potential use in industrial applications in an effort to reduce the world dependence on petroleum and fossil fuels. However the technical challenges associated with commercialization of bioethanol production are still significant. / M

Thesis (M.Sc.). / Written for the Dept. of Bioresource Engineering. Title from title page of PDF (viewed 2008/07/30). Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:23:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-10-24Bitstream added on 2014-06-13T19:28:58Z : No. of bitstreams: 1 zaneti_vm_me_araiq.pdf: 906459 bytes, checksum: 31326d4c24892f34266c70f06d8d025a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho foi utilizada a metodologia de superfície de resposta, por meio de delineamento composto central rotacional para investigar as melhores condições de produção de xilanase pelo fungo filamentoso Aspergillus niger. Este micro-organismo é considerado um bom produtor de enzimas xilanases, sendo que estas enzimas têm a capacidade de hidrolisar xilana em xilooligossacarídeos e xilose. Produtos assim obtidos estão sendo cada vez mais utilizados em rações animais para melhoria da flora intestinal; para a produção de xilitol e também para a produção de álcool de segunda geração. A análise estatística dos resultados obtidos neste trabalho mostrou que as melhores condições de produção da enzima extracelular foram: pH 5,0, temperatura de 37 ºC, agitação de 80 rpm, e concentração de fonte de carbono de 2 % (p/v). Após a determinação das condições ideais, o extrato foi clarificado por filtração em caulim, e as proteínas assim obtidas foram precipitadas com acetona ocorrendo uma melhora sensível na atividade específica. Após filtração em Sephadex G-75 foi mostrada a presença de atividade xilanolítica em dois picos, e as frações referentes ao segundo pico foram reunidas e submetidas à coluna de troca iônica DEAE-Trisacryl, na qual se constatou uma fração sendo eluída com 0,06 mol/L de NaCl, contendo atividade de xilanase. A SDS-PAGE da fração majoritária revelou uma única banda protéica com massa molar aparente de 34 kDa. A cromatografia em sílica gel P60 revelou que os produtos de hidrólise foram constituídos de xilooligossacarídeos, após 120 min de hidrólise / In the present work, response surface methodology was utilized, through appliance of rotational central composite design to investigate the best conditions of production of xylanase by the filamentous fungus Aspergillus niger. This microorganism is considered a good producer of xylanase enzyme, which has the ability to hydrolyze hemicelluloses in xylooligosaccharides and xylose. Products obtained this way are being increasingly utilized in animal feeding to improve the intestinal flora, to produce xylitol and also to produce second generation ethanol. The statistical analysis of the obtained results showed that the best conditions for the extracellular enzyme production were: pH 5.0, 37 ºC, 80 rpm shaking, and 2 % (w/v) carbon source concentration. After the determination of the ideal production conditions, the enzyme extract was clarified through filtration in kaolin, and the protein obtained were precipitated with acetone, with a sensitive increase in the specific activity. After molecular exclusion chromatography in Sephadex G-75 the presence of xylanolitic activity was shown in two peaks, and the fractions related to the second peak were collected and submitted to DEAE-Trisacryl ion exchange column, in which were observed fractions showing xylanase activity that was eluted with 0.06 mol/L NaCl. SDS-PAGE of the majority fraction revealed only one proteic band with apparent molar mass of 34 kDa. P60 silica gel chromatography revealed that the product of hydrolysis was constituted of small xylooligosaccharides released after 120 min of hydrolysis