Made available in DSpace on 2017-07-10T13:59:28Z (GMT). No. of bitstreams: 1 Dissertacao_ Nyessia versao finalissima 15-04-2015.pdf: 1194358 bytes, checksum: 0a6089c54d46aca60776ce97f1474515 (MD5) Previous issue date: 2014-11-28 / SIM (não especificado) / The aim of this study was to optimize the production of xylanase by Penicillium crustosum using Plackett-Burman the Design (BDP) and Central Composite Rotational Design (CCRD), and its application in the bleaching process of kraft pulp. The PBD-12 was carried out to screening the significant variables of the compounds of the culture medium: NaNO3; KH2PO4; MgSO4 7H2O; KCl; Fe2(SO4)3, yeast extract, corn stover and initial pH under liquid static culture at 28 °C for 6 days. The variables corn stover, KH2PO4, and pH were significant at p <0.10 by DPB. Statistical analysis of the results obtained with CCRD exhibited the three variables (KH2PO4 0.15%, corn stover 2% and initial pH 6.0) that showed significant effects at p <0.05, and the maximum production of xylanase was 50 U/mL, 14 times higher compared to enzyme activity before optimization. The treatment of the kraft pulp with P. crustosum xylanase showed a significant reduction in kappa number (5.27 Kappa points and efficiency (35.04%). Thus, there is evidence of the potential application of xylanase produced by P. crustosum in the bleaching process of kraft pulp in paper industry / As xilanases são complexos enzimáticos pertencentes ao grupo das glicosidases, e são capazes de atuar em vários sítios da cadeia do xilano e degradá-lo em xilooligossacarídeos, xilotrioses, xilobioses e xiloses. As xilanases são utilizadas nos diversos setores industriais, como biobranqueamento de celulose, na melhoria da textura e do volume do pão, clareamento de sucos e vinho, melhoria do valor nutricional de ração de animais monogástricos. Este trabalho teve como objetivo otimizar a produção de xilanase pelo Penicillium crustosum utilizando o Delineamento Plackett-Burman (DPB) e Delineamento Composto Central Rotacional (DCCR), bem como aplicação da xilanase otimizada no processo de branqueamento da polpa de celulose. A seleção dos componentes de meio de cultivo: NaNO3; KH2PO4; MgSO4·7H2O; KCl; Fe2(SO4)3, extrato de levedura, palha de milho e pH inicial foi realizada utilizando DPB-12 em condições de cultivo líquido estacionário a 28ºC por 6 dias. As variáveis palha de milho, KH2PO4, e pH apresentaram efeitos significativos em p<0,10 por DPB. A análise estatística dos resultados obtidos com DCCR exibiram as três variáveis (KH2PO4 0,15 %, palha de milho 2% e pH inicial 6,0) que mostraram efeitos significativos em p<0,05, e a produção máxima de xilanase foi de 50 U/mL, 14 vezes superior em comparação à atividade enzimática antes da otimização. O tratamento da polpa celulósica com a xilanase de P. crustosum mostrou uma redução significativa do número kappa em 5,27 pontos e eficiência Kappa de 35,04%. Dessa forma, evidencia-se o potencial de aplicação da xilanase produzida por P. crustosum no processo de branqueamento da polpa kraft de Eucaliptos para indústria de papel e celulose

Les espèces du complexe Scedosporium apiospermum sont des agents pathogènes émergents qui se situent au deuxième rang parmi les champignons filamenteux rencontrés au cours de la mucoviscidose. Ils sont omniprésents et particulièrement rencontrés dans les zones polluées. En dépit de leur importance clinique, nos connaissances sur leur biologie moléculaire et leur physiologie restent limitées. Chez les champignons, la paroi constitue un bouclier protecteur face à des conditions environnementales défavorables, et joue un rôle essentiel dans la pathogénicité. Ici, nous avons étudié les changements dynamiques de la paroi des conidies de S. boydii, l’une des deux espèces majeures de ce complexe avec S. apiospermum, avec pour objectif d'identifier des facteurs de virulence potentiels. En utilisant une large variété de techniques, allant de la microscopie électronique à balayage ou à transmission à l’analyse protéomique des protéines à ancre glycosylphosphatidylinositol (GPI) en passant par la microélectrophorèse et la partition de phase, la cytométrie en flux, la microscopie de force atomique, la résonance paramagnétique électronique, ou encore des techniques moléculaires, nous avons mis en évidence diverses modifications qui se produisent dans la paroi pendant la maturation et la germination des conidies de S. boydii et nous avons identifié la DHN-mélanine ainsi qu'un nombre important de protéines à ancre GPI. Enfin, nous avons fourni la première séquence complète du génome de S. apiospermum qui appuierait les différents domaines de la recherche sur ces champignons que ce soit pour l’étude des mécanismes pathogènes ou pour des applications biotechnologiques. / Species of the Scedosporium apiospermum complex are emerging human pathogens which rank the second, after Aspergillus fumigatus, among the filamentous fungi colonizing the airways of patients with cystic fibrosis. These fungi are ubiquitous in nature and particularly encountered in polluted areas. Despite their clinical relevance, our knowledge about their molecular biology and physiology remains rather limited. In fungi, the cell wall forms a protective shield against adverse environmental conditions, and therefore plays a key role in pathogenesis, which makes it an interesting target for antifungal drug development. Here, in an attempt to identify potential virulence factors, we investigated the dynamic changes of the cell wall of conidia in S. boydii, one of the main pathogenic species within this species complex with Scedosporium apiospermum. Using various techniques, ranging from scanning and transmission electron microscopy to proteomic analysis of glycosylphosphatidylinositol (GPI)- anchored proteins, through two-phase partitioning and microelectrophoresis, atomic force microscopy and chemical force spectroscopy, flow 5 cytometry, electron paramagnetic resonance and molecular techniques, we highlighted various modifications occurring in the cell wall during maturation and germination of S. boydii and we identified DHN-melanin as well as a substantial number of GPI-anchored proteins in the cell wall. Finally, we provided the first publicly available genome sequence of S. apiospermum that would support various research fields on these fungi whether for understanding their pathogenic mechanisms or for various biotechnological applications.

Slamsvällning orsakar stora problem i avloppsreningsverk med biologisk rening i aktivt slamprocesser. Slamsvällning orsakas av filamentösa (trådformiga) bakterier, som inverkar negativt på slammets sedimenteringsegenskaper. Himmerfjärdens vattenreningsverk har drabbats av detta problem som leder till ett stabilt lager av slam på ytan av sedimenteringsbassängen som inte sedimenterar. För att lösa detta problem behandlades returslammet från sedimenteringsbassängen med ozon för att minska mängden filamentösa bakterier i returslamflödet. Ozon är en starkt oxiderande gas, som är väl användbar för icke-specifik bekämpning av slamsvällning. När ozon kommer i kontakt med den filamentösa bakteriens cellvägg penetreras det in i cellen, varvid cellen lyserar. Ozonbehandlingen resulterade i en förminskning av antalet filamentösa bakterier. Ozonbehandling av returslam förbättrade sedimenteringsegenskaperna hos svällande slam utan att påverka andra viktiga mikrobiologiska processer t.ex. nitrifikation. / Bulking sludge causes major problems in wastewater treatment plants that deal with biological nutrient removal in activated sludge processes. Bulking sludge is caused by filamentous bacteria, which have a negative impact on the sludge settling properties. Himmerfjärden wastewater treatment plant suffers from this type of problem with bulking sludge which creates a stable layer at the surface that does not settle in the clarifier. In order to solve this problem, on site generated ozone was used to decrease the amount of filamentous bacteria in the return activated sludge flow. Ozone is a strong oxidant is suitable for non-specific bulking control. It stresses the filamentous bacteria causing inactivation through cell wall disintegration. The ozone treatment resulted in decreased abundance of filamentous bacteria. Ozone treatment of the recycled activated sludge improves the settling properties of bulking sludge, without interfering with other important microbiological processes e.g. nitrification.

The activated sludge process efficiency depends on separation of microbial cells from treated wastewater. Separation can fail due to a number of problems. One of these problems is sludge bulking which is non-settling situation of biomass. Former studies showed that phosphorus deficiency caused filamentous sludge bulking with increasing magnesium ion concentrations. The main objectives of this study are to find out the effect of magnesium ions on sludge properties in phosphorus deficient medium and to determine if there is any bulking. Three different concentrations of magnesium (0.5, 5, 15 meq/L) were added to three bioreactors which contained phosphorus deficient medium. In first set C: N: P ratio was 100:5:0.05. In second set, C:N:P ratio was elevated to 100:5:1. At steady state, physical characteristics including sludge volume index (SVI), viscosity, turbidity and dewaterability were determined. Besides concentration of extracellular polymeric substances (EPS) as well as conductivity was measured. By using API kits, bacterial identification was achieved. In first set phosphorus deficiency and increasing magnesium ion concentration caused filamentous bulking. Carbohydrate content of extracellular polymeric substance significantly increased by magnesium addition. Dewaterability of the system got worse and viscosity decreased. Sludge Volume Index (SVI) indicated severe bulking at all magnesium concentrations. By using biochemical tests microorganisms dominant in the system were determined In second set, all of the parameters indicated healthy flocculation. By magnesium addition, EPSp and EPSc increased. Dewaterability and settleability, improved by the presence of phosphorus with close values measured at different magnesiuim concentrations. Nocardia related genera of Corynebacterium and Enteric microorganisms were identified.

Identification of fungi is based on macroscopic observations of morphology and microscopic characteristics. These conventional methods are time-consuming and requires expert knowledge. For the past years Matrix-assisted laser desorption ionization-time of flight mass spectrometry has been used for routine bacterial identification in clinical laboratories but not yet in the same extension for fungi. In this study three preanalytic preparation methods for fungi were evaluated in order to shorten the processing time in routine laboratory performance. Clinically relevant strains (n=18) of molds and dermatophytes were cultivated on agar plates and prepared according to the different preparation methods for protein extraction. Each strain was analyzed in quadruplicate by the MALDI Biotyper and the database Filamentous Fungi Library 1.0. The results showed that the genus and species identification rates of the least time-consuming direct extraction method were 33% and 11% respectively. Using the formic acid extraction method, the genus and species identification rates were 83% and 44%, respectively. For the longest sample preparation method, liquid media culturing before formic acid extraction, successfully identified all strains except one, which resulted in an identification rate of 94% and 78% respectively. This study shows that preparing samples in cultured liquid media MADLI-TOF MS effectively identified fungal strains to both genus- and species-level. This method was however too time-consuming and cumbersome to be recommended as a replacement to the conventional method. Future studies should be aimed at expanding the reference library and making the direct extraction method more reproducible in terms of obtaining more reliable identification rates.

Kinesins are molecular motors that transport intracellular cargos along microtubules (MTs) and influence the organization and dynamics of the MT cytoskeleton. Their force-generating functions arise from conformational changes in their motor domain as ATP is bound and hydrolyzed, and products are released. In the budding yeast Saccharomyces cerevisiae, the Kar3 kinesin forms heterodimers with one of two non-catalytic kinesin-like proteins, Cik1 and Vik1, which lack the ability to bind ATP, and yet they retain the capacity to bind MTs. Cik1 and Vik1 also influence and respond to the MT-binding and nucleotide states of Kar3, and differentially regulate the functions of Kar3 during yeast mating and mitosis. The mechanism by which Kar3/Cik1 and Kar3/Vik1 dimers operate remains unknown, but has important implications for understanding mechanical coordination between subunits of motor complexes that traverse cytoskeletal tracks. In this study, we show that the opportunistic human fungal pathogen Candida albicans (Ca) harbors a single version of this unique form of heterodimeric kinesin and we present the first in vitro characterization of this motor. Like its budding yeast counterpart, the Vik1-like subunit binds directly to MTs and strengthens the MT-binding affinity of the heterodimer. However, in contrast to ScKar3/Cik1 and ScKar3/Vik1, CaKar3/Vik1 exhibits weaker overall MT-binding affinity and lower ATPase activity. Preliminary investigations using a multiple motor motility assay indicate CaKar3/Vik1 may not be motile. Using a maltose binding protein tagging system, we determined the X-ray crystal structure of the CaKar3 motor domain and observed notable differences in its nucleotide-binding pocket relative to ScKar3 that appear to represent a previously unobserved state of the active site. Together, these studies broaden our knowledge of novel kinesin motor assemblies and shed new light on structurally dynamic regions of Kar3/Vik1-like motor complexes that help mediate mechanical coordination of its subunits. / Thesis (Master, Biochemistry) -- Queen's University, 2012-02-29 17:15:03.654

Consumption of frozen chicken breaded has increased considerably in recent decades, since they are practical and tasty, able to meet the needs of consumers. The intrinsic characteristics of this product are favorable to the proliferation of pathogenic and spoilage micro -organisms and the application of low temperatures has been the method used to extend the life of these breaded meat. Microbiological contamination can originate in breaded raw material used for production or produced during the handling and processing operations and multiplication of these microorganisms during storage can modify the sensory and nutritional properties of the food, and pose a problem food security. Due to their ability to overcome barriers of temperature and water activity, fungi are the main micro -organisms able to degrade the group of frozen foods, which, besides the appearance and deteriorating economic losses, represents a public health problem by the possibility production of mycotoxins in the product and consumer exposure. The aim of this study was to identify the main species of filamentous fungi involved in the deterioration of frozen chicken breaded , check secondary metabolites produced by the same and assess the growth of the two predominant species when exposed to low temperatures and, in parallel, to determine the temperature at counters freeze 6 supermarkets in the city of Santa Maria - RS. The predominant species involved in the deterioration of frozen chicken breaded were Penicillium glabrum, Penicillium polonicum, Penicillium manginii, Penicillium solitum and Penicillium crustosum. The analysis of the secondary metabolite profile showed the capacity to synthesize mycotoxins as cyclopiazonic acid citroviridina, roquefortina C, penitren A and verrucosidina by some isolates. The results demonstrated that the fungus P. polonicum, was able to form visible colonies on the surface of frozen chicken breaded kept at -5°C for 120 days. For P. glabrum the lowest growth was observed that temperature was 0°C. A ' spot ' supermarkets temperature analysis revealed temperature higher than -5°C in at least one of the time points evaluated, and 4 supermarkets 6 (66%) had at least one peak temperature above 0°C, with a maximum of 9.8 °C. Since there is occurrence of storage temperatures at which frozen foods fungi P. polonicum and P. glabrum could develop and knowing that these species have the ability to produce toxic metabolites, emphasize the need for greater attention to research related to fungal spoilage of frozen foods, source of contamination, methods of prevention and possible implications of the consumption of contaminated for public health products. / O consumo de empanados congelados de frango aumentou consideravelmente nas últimas décadas, uma vez que são produtos práticos e saborosos, capazes de satisfazer as necessidades dos consumidores. As características intrínsecas deste produto são favoráveis à proliferação de micro-organismos patogênicos e deteriorantes e a aplicação de baixas temperaturas tem sido o método mais empregado para prolongar a vida útil destes empanados cárneos congelados. A contaminação microbiológica em empanados pode se originar da matéria-prima utilizada para sua elaboração ou se produz durante a manipulação e operações de processamento e a multiplicação destes micro-organismos durante a estocagem pode modificar as propriedades sensoriais e nutricionais do alimento, além de representar um problema de segurança alimentar. Devido a sua habilidade em superar barreiras de temperatura e atividade de água, os fungos são os principais micro-organismos capazes de deteriorar o grupo dos alimentos congelados, o que, além do aspecto deteriorativo e perdas econômicas, representa um problema de saúde pública pela possibilidade de produção de micotoxinas no produto e exposição do consumidor. O objetivo deste estudo foi de identificar as principais espécies de fungos filamentosos envolvidas na deterioração de empanados congelados de frango, verificar metabólitos secundários produzidos pelas mesmas e avaliar o crescimento das duas espécies predominantes quando expostas à baixas temperaturas e, em paralelo, determinar a temperatura em balcões de congelamento de 6 supermercados da cidade de Santa Maria-RS. As espécies predominantes envolvidas na deterioração de empanados congelados de frango foram Penicillium glabrum, Penicillium polonicum, Penicillium manginii, Penicillium solitum e Penicillium crustosum. A análise do perfil de metabólitos secundários revelou capacidade de síntese de micotoxinas como ácido ciclopiazônico, citroviridina, roquefortina C, penitrem A e verrucosidina por alguns isolados. Os resultados demonstraram que o fungo P. polonicum, foi capaz de formar colônias visíveis na superfície dos empanados congelados de frango conservados à -5°C aos 120 dias. Para P. glabrum a menor temperatura que foi observado crescimento foi 0ºC. A análise in loco da temperatura dos supermercados revelou temperatura superior a -5°C em pelo menos um dos momentos avaliados, sendo que 4 de 6 supermercados (66%) apresentaram pelo menos um pico de temperatura acima de 0 °C, com um máximo de 9,8°C. Visto que há ocorrência de temperaturas de armazenagem de alimentos congelados nas quais os fungos P. polonicum e P. glabrum poderiam se desenvolver e sabendo-se que estas espécies têm a capacidade de produzir metabólitos tóxicos, ressalta-se a necessidade de maior atenção para pesquisas relacionadas a deterioração fúngica de alimentos congelados, origem da contaminação, formas de prevenção e possíveis implicações do consumo de produtos contaminados para a saúde pública.

Submitted by CÁROL CABRAL TERRONE null (36025505837) on 2018-01-09T15:20:42Z No. of bitstreams: 1 Tese - Cárol Terrone.pdf: 3140738 bytes, checksum: 563a37f8e4725bc76f326c128aae84bf (MD5) / Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2018-01-10T16:59:21Z (GMT) No. of bitstreams: 1 terrone_cc_dr_rcla.pdf: 3025804 bytes, checksum: 817c25d1a9eef55ee5d3fb7555bd7982 (MD5) / Made available in DSpace on 2018-01-10T16:59:21Z (GMT). No. of bitstreams: 1 terrone_cc_dr_rcla.pdf: 3025804 bytes, checksum: 817c25d1a9eef55ee5d3fb7555bd7982 (MD5) Previous issue date: 2017-11-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Biomassa lignocelulósica é a principal fonte de carbono renovável no planeta. Seus constituintes majoritários são celulose, hemiceluloses e lignina. Hemiceluloses são polissacarídeos ramificados sendo o principal tipo as xilanas, estruturas com cadeia principal de xilose. Dentre as diversas enzimas hidrolíticas, que atuam sobre a estrutura de xilanas, estão as α-L-arabinofuranosidases, que catalisam a hidrólise de ligações entre α-L-arabinofuranosídeos e a cadeia principal do polissacarídeo. Neste trabalho, uma linhagem de Aspergillus hortai CRM1919, isolada de solo próximo a lagoas salinas e alcalinas da região da Nhecolândia no Pantanal Matogrossense, foi utilizada para produzir α-L-arabinofuranosidases. Resíduos agroindustriais foram utilizados como substrato para o cultivo do fungo. O objetivo principal foi otimizar a produção de α-L-arabinofuranosidases e aumentar a produção a fim de se obter um filtrado enzimático rico nessa atividade, para posteriormente purificá-la e aplicá-la na degradação de biomassa. A linhagem foi cultivada em meio líquido de Vogel suplementado com diferentes substratos, dentre eles alguns subprodutos da agroindústria. As maiores produções de α-arabinofuranosidases ocorreram nos cultivos com polpa cítrica e casca de laranja a 1% (m/v) em cultivos estáticos por 4 dias, com pH inicial de 2,5 e temperatura de 30 ºC. Após todas as etapas de otimização, o extrato bruto apresentou atividade quinze vezes maior do que nos cultivos iniciais. A enzima foi purificada por uma estratégia de três etapas, sendo uma precipitação com sulfato de amônio, na concentração de 25 a 65%, uma cromatografia de troca iônica e outra de exclusão molecular, apresentando ao final uma recuperação de 10,1% com um fator de purificação de 58,7. As características da α-L-arabinofuranosidase purificada foram determinadas, sendo pH ótimo de 4,0 e temperatura ótima de 60 ºC, meia vida a 30 e 40 ºC de 265 e 230 minutos, respectivamente. A maior estabilidade da enzima ao pH ocorreu em pH 5,0, A atividade enzimática foi reduzida na presença de Zn+2, PMSF, SDS e etanol a 20%, mas foi ativada na presença de Mg+2, Na+, EDTA, Tween 20, Tween 80 e Triton X-100. A α-arabinofuranosidase apresentou tolerância a presença de 0,5 e 1,0 M de NaCl no meio reacional, e alta estabilidade nas concentrações de 0,5, 1,0, 2,0 e 4,0 M de NaCl. Os parâmetros cinéticos para o substrato ρ-nitrofenil-α-L-arabinofuranosídeo foram Km de 8,73 mM, Vmáx de 7,91 μmol/min.mg e Kcat de 0,59/min. A enzima purificada apresentou afinidade apenas sobre o substrato ρ-nitrofenil-α-L-arabinofuranosídeo. Na caracterização das biomassas in natura, o bagaço de cana-de-açúcar apresentou em sua composição 30% de celulose, 16% de hemiceluloses e 20% de ligninas totais, enquanto bagaço de malte apresentou 20% de celulose, 20% de hemiceluloses e 20% de ligninas totais. Na caracterização da hemicelulose extraída, a de bagaço de cana-de-açúcar apresentou composição em açúcares redutores de 7,8% de glicose, 23,7% de xilose e 2,6% de arabinose; a hemicelulose de bagaço de malte apresentou em sua composição 20,6% de glicose, 28,3% de xilose e 9,4% de arabinose. A hidrólise das hemiceluloses e de xilanas comerciais foi realizada na presença da α-arabinofuranosidase purificada e do filtrado bruto de cultivo contendo a α-arabinofuranosidase, associados com uma xilanase purificada, também produzida por Aspergillus hortai. Em ambos os casos foi possível verificar a cooperação entre enzimas do complexo xilanolítico e a atuação sequencial de cada uma na hidrólise das estruturas de xilano. / Lignocellulosic biomass is the main source of renewable carbon on the planet. Its major constituents are cellulose, hemicelluloses and lignin. Hemicelluloses are branched polysaccharides being the main type the xylan, xylose main chain structures. Among the various hydrolytic enzymes that act on the xylan structure there are the α-L-arabinofuranosidases, which catalyze the hydrolysis of linkages between α-L-arabinofuranosides and the polysaccharide main chain. In this work, a strain of Aspergillus hortai CRM1919, isolated from soil near saline and alkaline lagoons of the Nhecolândia region in Pantanal Matogrossense, was used to produce α-L-arabinofuranosidases. Agroindustrial wastes were used as substrate for the fungus cultivation. The main objective was to optimize the production of α-L-arabinofuranosidases and increase the yield in order to obtain a rich enzymatic filtrate in this activity, to later purify it and apply it in the hydrolysis of biomass. The strain was cultivated in Vogel liquid medium supplemented with different substrates, among them some by-products of agroindustry. The highest production of α-arabinofuranosidases occurred in cultures with citrus pulp and orange peel at 1% (w/v) in static cultures for 4 days, with an initial pH of 2.5 and temperature of 30 ºC. After all the optimization steps, the crude extract presented activity fifteen times higher than the initial cultures. The enzyme was purified by a three-step strategy, with ammonium sulfate precipitation at 25-65% concentration, ion exchange chromatography and molecular exclusion chromatography, with recovery of 10.1% and purification fold of 58.7. The characteristics of the purified α-L-arabinofuranosidase were determined, being optimum pH of 4.0 and optimum temperature of 60 °C, half-life at 30 and 40 °C of 265 and 230 minutes, respectively. The higher stability of the enzyme to pH occurred at pH 5.0. Enzymatic activity was reduced in the presence of Zn+ 2, PMSF, SDS and 20% ethanol and was activated in the presence of Mg+ 2, Na+, EDTA, Tween 20, Tween 80 and Triton X-100. The α-arabinofuranosidase presented tolerance to the presence of 0.5 and 1.0 M NaCl in the reaction medium, and high stability at the concentrations of 0.5, 1.0, 2.0 and 4.0 M NaCl. The kinetic parameters for the ρ-nitro phenyl-α-L-arabinofuranoside substrate were Km of 8.73 mM, Vmax of 7.91 μmol / min.mg and Kcat of 0.59 / min. The purified enzyme had affinity only on the ρ-nitro phenyl-α-L-arabinofuranoside substrate. In the characterization of in natura biomasses, sugarcane bagasse presented 30% cellulose, 16% hemicelluloses and 20% total lignins, while brewer’s spent grain presented 20% cellulose, 20% hemicelluloses and 20% total lignins. In the characterization of extracted hemicellulose, the sugarcane bagasse presented composition in reducing sugars of 7.8% of glucose, 23.7% of xylose and 2.6% of arabinose; the hemicellulose of brewer’s spent grain presented 20.6% glucose, 28.3% xylose and 9.4% arabinose. Hydrolysis of the hemicelluloses and commercial xylans was performed in the presence of the purified α-arabinofuranosidase and the crude culture filtrate containing α-arabinofuranosidase, associated with a purified xylanase, also produced by Aspergillus hortai. In both cases it was possible to verify the cooperation between xylanolytic complex enzymes and the sequential action of each one in the hydrolysis of the xylan structure.

Made available in DSpace on 2014-06-11T19:32:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-01-12Bitstream added on 2014-06-13T21:05:12Z : No. of bitstreams: 1 rodrigues_a_dr_rcla.pdf: 1112229 bytes, checksum: f59b4675edb860a1b20d6b5f1f7e6dc9 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / As formigas da tribo Attini são conhecidas pela complexa simbiose que mantêm com fungos, os quais cultivam como alimento. É sabido que além desse fungo, outros microrganismos podem ser encontrados nos ninhos desses insetos e estudos prévios apontaram que alguns microfungos (i.e. leveduras e fungos filamentosos) podem ser importantes nessa simbiose. O objetivo do presente trabalho foi avaliar o papel desses microfungos associados aos jardins dessas formigas. Analisando várias espécies do gênero Acromyrmex do sul do Brasil, demonstrou-se que as formigas importam uma comunidade diversa de microfungos para seus ninhos, provavelmente provenientes do solo e do substrato vegetal que as formigas utilizam para cultivar seu fungo. Num segundo estudo, avaliando formigas Attini da América do Norte (Atta texana, Trachymyrmex septentrionalis e Cyphomyrmex wheeleri) observou-se que a estrutura das comunidades de microfungos nos jardins desses insetos não se correlaciona com a variação sazonal, sugerindo que não existam relações espécie-específicas entre as formigas e os microfungos. Apesar de tais microrganismos não serem especialistas dos jardins desses insetos, é sugerido que os microfungos atuem como antagonistas do fungo simbionte. Ainda, descobriu-se que o parasita especializado Escovopsis spp. parece ser menos freqüente nas populações de formigas da América do Sul em relação as Attini da América Central, porém estudos adicionais são necessários para estabelecer a epidemiologia desse parasita nos ninhos das Attini. Num terceiro estudo, demonstrou-se que leveduras presentes nos jardins de fungos da formiga cortadeira A. texana inibem o crescimento de Escovopsis spp., sugerindo que esses insetos utilizam outros microrganismos, além das bactérias presentes em suas cutículas (Pseudonocardia spp.), para inibir esse parasita. Esse achado traz importantes implicações para essa... / Ants in the tribe Attini are well-known social insects that maintain a symbiotic relationship with fungi which they cultivate as food. Besides of the cultivated fungi, fungus gardens contain several other microorganisms considered to be potential players in this symbiosis. The aim of the present study was to evaluate the possible roles of microfungi (i.e. yeasts and filamentous fungi) in attine gardens. Our microbial profiling of gardens from several species in the genus Acromyrmex from South Brazil revealed that ants can harbor a diverse community of microfungi that probably originated from the surrounding soil or from the substrate used to manure the cultivated fungus. In this sense, additional studies of North American attine species (Atta texana, Trachymyrmex septentrionalis and Cyphomyrmex wheeleri) demonstrated that the structure of microfungal communities in gardens of these ants did not correlate with seasonal changes over a one year period, again suggesting there are no species-specific relationships among ants and microfungi species. Although, the microfungi are not specialized parasites of the attine ant-fungus symbiosis we suggest they can be considered antagonists to the cultivated fungus. Moreover, we demonstrated that the specialized parasite Escovopsis spp. is probably less frequent in South America than in Central America and we reinforce that additional studies are necessary to unravel the epidemiology of this parasite in attine gardens. In another study, we showed that yeasts isolated from gardens of the leafcutter ant A. texana can significantly inhibit the growth of Escovopsis sp. This interesting finding suggests that attine ants may use additional microbes to protect their gardens against Escovopsis spp. and not only actinomycete bacteria (Pseudonocardia spp.) found in their cuticles. Finally, we studied microfungi relationships with female alates (gynes) in two... (Complete abstract click electronic access below)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Um dos grandes desafios na produção biotecnológica é a produção de insumos de alto valor agregado a um baixo custo. Neste contexto, o fungo filamentoso Cunninghamella elegans apresenta em sua parede celular grandes quantidades de quitina e quitosana, como também é capaz de produzir biossurfactantes. A quitina e quitosana apresentam um vasto campo de aplicações biotecnológicas, e na biorremediação vem sendo utilizado na remoção e recuperação de diferentes resíduos, biotransformação de poluentes e descoloração de efluente têxtil. Estes biopolímeros possuem estruturas lineares, com unidades monoméricas &#946;-1,4-N-acetil-D-glicosamina e &#946;-1,4-D-glicosamina, respectivamente. Por outro lado, os biossurfactantes são compostos sintetizados por micro-organismos, apresentando propriedades como a redução da tensão superficial e interfacial, emulsificação, solubilização e dispersão de fases, sendo muito aplicado na indústria petroquímica. Estudos com Cunninghamella elegans UCP/WFCC 0542 foram realizados com objetivo de avaliar o seu potencial biotecnológico para a produção de quitina, quitosana e biossurfactante com a utilização de resíduos agroindustriais (milhocina e óleo de soja pós-fritura), através de um delineamento central composto rotacional de 2. Os biopolímeros quitina e quitosana foram obtidos através de tratamento álcali-ácido, com hidróxido de sódio 1M, e posterior emprego de ácido acético a 2%. As propriedades tensoativas do biossurfactante foram avaliadas pela determinação da tensão superficial do líquido metabólico livre de células. A produção de biomassa por C. elegans foi de 8,12 g/L de com rendimentos de 0,095 mg/g de quitina e 0,036 mg/g de quitosana, com um grau de desacetilação de 87,44%, na condição proposta. O biossurfactante obtido na condição 8 do planejamento com 2,15% de milhocina e 5,22% de óleo de soja pós-fritura demonstrou a melhor tensão superficial com 28,20 mN/m-1 e apresentou estabilidade frente a diferentes condições ambientais, possuindo caráter aniônico e sua composição bioquímica preliminar sugere que o biossurfactante isolado seja constituído por proteínas e lipídeos. Também este se mostrou eficiente na remoção de compostos hidrofóbicos derivados do petróleo, com remoção de 55,15% de óleo de motor, 71,42% de petróleo bruto, 77,46% de querosene e 96,41% de óleo diesel em areia de praia. Testes de toxicidade do biossurfactante com sementes de Brassica oleracea provaram seu caráter atóxico. Os resultados obtidos demonstram o potencial biotecnológico de C. elegans a partir substratos agroindustriais alternativos e de baixo custo, possibilitando o seu emprego em processo de biorremediação na recuperação ambiental. / One of the biggest challenges in biotechnological production is to produce high value-added products at a low cost. In this context, the filamentous fungus Cunninghamella elegans presents in its cell wall large amounts of chitin and chitosan, but is also able to produce biosurfactants. Chitin and chitosan has a vast field of biotechnological applications, and the bioremediation has been used in the removal and recovery of different waste, pollutant biotransformation and textile effluent discoloration. These biopolymers have linear structures with monomeric units &#946;-1,4-N-acetyl-D-glucosamine and &#946;-1,4-D-glucosamine, respectively. Furthermore, the surfactants are compounds synthesized by micro-organisms having properties such as reducing surface and interfacial tension, emulsification, solubilization and dispersion phases, being widely applied in the petrochemical industry. Studies with C. elegans UCP/WFCC 0542 were performed in order to evaluate their biotechnological potential for the production of chitin, chitosan and biosurfactant with the use of agroindustrial residues (corn steep liquor and soybean oil waste), using a central composite design rotational 2. The biopolymers chitin and chitosan were obtained by alkali-acid treatment with 1M sodium hydroxide, and subsequent use of 2% acetic acid. The surface-active properties of the biosurfactant were evaluated by measuring the surface tension of the metabolic liquid cell-free. Biomass production by C. elegans was 8.12 g/L with yields of 0.095 mg/g chitin and 0.036 mg/g of chitosan with a deacetylation degree of 87.44% in the proposed condition. The biosurfactant obtained in condition 8 of planning with 2.15% of corn steep liquor and 5.22% soybean oil waste has demonstrated the best surface tension with 28.20 mN/m-1 and showed stability against to different environmental conditions, having anionic character and its preliminary biochemical composition suggests that the isolated biosurfactant consists of proteins and lipids. Also this proved effective in the removal of petroleum derivatives hydrophobic compounds, removing 55.15% of motor oil, 71.42% of crude petroleum, 77.46% of kerosene and 96.41% of diesel oil in sand beach. Biosurfactant toxicity tests with Brassica oleracea seeds proved their non-toxic nature. The results show the biotechnological potential of C. elegans from alternative and low cost agroindustrial substrates, allowing its use in bioremediation process in environmental recovery.