No description available.

Orientador: Lorena Benathar Ballod Tavares. / Co-orientador: Cristiane Vieira Helm. / Dissertação (Mestrado em Engenharia Ambiental) - Programa de Pós-Graduação em Engenharia Ambiental, Centro de Ciências Tecnológicas.

In this study the enzymatic activity of adsorbed Thermomonospora fusca E��� and Trichoderma reesei CBHI cellulases were investigated using fluorescence techniques. In particular, cellulases were allowed to contact hydrophobic polystyrene surfaces under conditions of different solution concentrations, and adsorption times. Each of these variables is known to have a potential effect on enzyme structure and activity at an interface. Enzymatic activity was measured after partial elution of the adsorbed layer with both protein-free buffer and the surfactant, dodecyltrimethylammonium bromide. For E��� at high concentration (0.5 mg/ml), adsorbed enzyme activity decreased about 20% in increasing adsorption time from 0.25 h to 24 h. At low concentration (0.001 mg/ml), adsorbed enzyme activity decreased by one order of magnitude during a 24 h period. CBHI layers lost activity only after a sufficiently long contact time with the surface, and this effect was not strongly dependent on enzyme concentrations in solution. These findings were explained with reference to structural changes undergone by adsorbed enzyme as a function of time and available interfacial area. / Graduation date: 2000

Graduation date: 1999

There are generally four factors recognized as delimiting in the study of lignocelluloses for fuel ethanol production, viz., the source of the cellulase-system and its quality characteristics for cellulose hydrolysis, the substrate and pretreatment method, the process for cellulase production and bioreactor design, and the ability of yeast to ferment mixed hexose and pentose sugars. Wheat straw (WS) and T. reesei mutants were used in the study to evaluate the production of cellulase-systems. Hydrolysis of cellulose revealed the superiority of mild NaOH pretreatment over steam explosion for cellulase production with T. reesei MCG 80 and QMY-1. Response surface models were capable of predicting that NaOH could be used for the pretreatment of WS at 4% (w/w) without urea in the fermentation medium to yield optimum filter paper activity (FPA) of 9.9 IU/mL (247 IU/g WS) and beta-glucosidase activity ($ beta$GA) of 6.4 IU/mL (159 IU/g WS) under solid-state fermentation (SSF) conditions. Multiple regression analysis with multiple coefficients of correlation, R, between 0.957 and 0.99 from the experimental data showed close agreement between the cellulase activities (FPA and $ beta$GA) from the experiments and predicted values. / The superiority of SSF over liquid-state fermentation (LSF) in the production of cellulase-systems was also established, and a prototype pan-bioreactor showed good potential for upgrading cellulase production under SSF conditions. The economics of fuel ethanol production was considered in the optimization model that sought to establish threshold cellulase loadings needed to achieve maximum cellulose hydrolysis for fermentation. High substrate concentrations of up to 7.5% were hydrolyzed with cellulase loadings of 24-30 IU/g and fermented by Pichia stipitis to achieve 90-100% conversion into ethanol. / Crude unextracted cellulase yielded over 90% hydrolysis of delignified wheat straw and proved to be better than extracted cellulase and commercial cellulases for the hydrolysis of pure cellulose and pretreated wheat straw. Studies were also conducted to demonstrate the importance of the ratio of $ beta$GA- to FPA in cellulose hydrolysis which showed that ratios closer to one (1), produced more sugars and lowered the cellobiose content in the hydrolysates. It was also shown that the source of the cellulase is important in eliminating the accumulation of cellobiose during hydrolysis as was demonstrated with cellulase from mixed cultures of T. reesei and Aspergillus phoenicis. Higher $ beta$GA from the latter were implicated since A. phoenicis is a good $ beta$-glucosidase producer. / Delignified wheat straw at 5% concentration when subjected to separate hydrolysis and fermentation and simultaneous hydrolysis and fermentation resulted in similar volumetric productivities (g/L/h) of ethanol.

No description available.

Thesis (doctoral)--University of Helsinki, 2002. / Includes bibliographical references. Also available on the World Wide Web.

Cultivation of edible mushrooms in the world is becoming increasingly popular. People are increasingly aware of their positive effects and therefore are mushrooms used not only in restaurants but also increasingly in human and veterinary medicine. With their growing, but also associated infestation of cultivated cultures of mushrooms by pests and diseases. The farms are most often appear green mold of the genus Trichoderma which cause considerable losses. When growing oyster mushroom is the biggest problem Trichoderma pleuroti, the cultivation of Agaricus is a Trichoderma aggressivum. Therefore, the research of protection against these fungi and important in recent years, importance. Presented work studies the tolerance selected strains of Pleurotus ostreatus against Trichoderma pleuroti and different heat treatments of the substrate. In experiments was examined relationship between Pleurotus ostreatus, Trichoderma pleuroti and Bacillus subtilis, as well as various forms of heat treatment of the substrate and its enrichment. The experiments were statistically analyzed using ANOVA. In the case of a common growth Trichoderma pleuroti and Bacillus subtilis was Trichoderma pleuroti considerably restricted, especially in the case of surface inoculation of Bacillus subtilis. Also in a common growth of Bacillus subtilis and Pleurotus ostreatus, Pleurotus ostreatus growth was limited by surface inoculation of Bacillus subtilis was to restrict the growth of Pleurotus ostreatus pronounced. In the case of the fermentation substrate and subsequent heat treatment, it was found that the enrichment of the substrate and its subsequent fermentation treatment is not suitable for the growth of mycelia of Pleurotus ostreatus. In case the substrate has been infected Trichoderma pleuroti the most appropriate treatment showed fermentation substrate and subsequent heat treatment at 60 ° C. Adding mingled substrate is not proved crucial for the growth of mycelium Pleurotus ostreatus.

SARAIVA, N. N. Estudo Químico do Fungo Antagonista Trichoderma harzianum. 2009. 126 f. Dissertação (Mestrado em Química) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2009. / Submitted by Daniel Eduardo Alencar da Silva (dealencar.silva@gmail.com) on 2014-11-26T21:03:46Z No. of bitstreams: 1 2009_dis_nnsaraiva.pdf: 5266253 bytes, checksum: 9c0b01f213d5766cc0d1e13d36747d71 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa(jairo@ufc.br) on 2014-12-22T16:24:31Z (GMT) No. of bitstreams: 1 2009_dis_nnsaraiva.pdf: 5266253 bytes, checksum: 9c0b01f213d5766cc0d1e13d36747d71 (MD5) / Made available in DSpace on 2014-12-22T16:24:31Z (GMT). No. of bitstreams: 1 2009_dis_nnsaraiva.pdf: 5266253 bytes, checksum: 9c0b01f213d5766cc0d1e13d36747d71 (MD5) Previous issue date: 2009 / The chemical potential of Trichoderma harzianum, an antagonist fungus, was investigated. The fatty acid composition of this fungus grown in Czapeck, peptone and potato, with different carbon source (glycose and manitol) in the later medium, was determined after GC/MS analysis. The following fatty acids, as their methyl esters, were identified: hexadecanoic (C16:0), octadecanoic (C18:0), 9-octadecenoic (C18:1) and 9,12-octadienoic (C18:2). From the organic extracts of the microorganism cultivated in peptone (16 days) and potatodextrose (21 days) broths, manitol and the antimicrobial viridiofungin A were isolated, respectively. Extracts and fractions were submitted to antitumor assays against the human cell tumor lines MDA-MB435 (mama), HCT-8 (colon) e SF-295 (glioblastoma) and five of them showed IC50 75 % in two or three cell lines. Alcohol dehydrogenases (ADHs) activity of T. harzianum was identified and this microorganism was used as biocatalyst in the reduction of (R)-carvone, acetophenone and six akylphenones. In most cases, the products of the bioreductions were obtained. / A investigação do potencial químico de Trichoderma harzianum, um fungo antagonista, foi realizada. A composição de ácidos graxos produzidos pelo fungo cultivado em Czapeck, peptona e caldo de batata, variando a fonte de carbono (glicose e manitol), nesse último meio, foi determinada por CG/EM. Foram identificados os seguintes ácidos graxos na forma dos seus ésters metílicos: hexadecanóico (C16:0), octadecanóico (C18:0), 9-octadecenóico (C18:1) e 9,12-octadienóico (C18:2). Dos extratos orgânicos do fungo cultivado em peptona por 16 dias e BD (Batata-dextrose) por 24 dias foi possível isolar o manitol e o composto antimicrobiano viridiofungina A, respectivamente. Extratos e frações foram submetidos a testes antitumorais frente às linhagens tumorais humanas MDA-MB435 (mama), HCT-8 (cólon) e SF-295 (glioblastoma) e cinco das frações testadas apresentaram CI50 75% em pelo menos duas linhagens tumorais. A atividade alcooldesidrogenases (ADHs) de T. harzianum foi identificada e o microrganismo foi empregado como biocatalisador na redução da (R)- carvona, acetofenona e seis alquilfenonas. Na maioria dos casos, os produtos de biorredução foram obtidos.

Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-12T14:01:35Z No. of bitstreams: 2 DISSERTAÇÃO Márcia Josefa da Silva.pdf: 1750850 bytes, checksum: d36504435c0ecdaffe970fd5045e35c0 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-12T14:01:35Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Márcia Josefa da Silva.pdf: 1750850 bytes, checksum: d36504435c0ecdaffe970fd5045e35c0 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-02-28 / CAPES / A biomassa lignocelulósica destaca-se como matéria-prima alternativa para a produção de combustíveis e outros produtos. Devido à alta complexidade desse material, é necessária uma hidrólise enzimática eficiente com a utilização de um pool enzimático adequado. O objetivo deste trabalho foi estudar o perfil de produção de enzimas celulolíticas e xilanolítica por Trichoderma reesei RUT C-30 em meios com diferentes capacidades de indução. A produção de enzimas foi realizada em biorreator de bancada (Bioflo 110) com 1,3 ou 3 L de volume de trabalho, nas seguintes condições: 500 rpm, 28° C, 2 vvm e pH 5,0. As fontes de carbono investigadas foram: lactose, xilana, pectina, celulose microcristalina, melaço, biomassa de palma forrageira e hidrolisado hemicelulósico. O hidrolisado foi obtido por tratamento hidrotérmico de bagaço de cana-de-açúcar em reator descontínuo de 20 L (Regmed AU/20), com volume de trabalho de 10 L e carga de sólidos de 5% (m/v), a 185°C, por 16 minutos. Em substratos solúveis, a determinação da concentração celular foi realizada por peso seco e as concentrações dos substratos foram obtidas por cromatografia líquida de alta eficiência. Ao final dos cultivos, foram isoladas proteínas extracelulares, que servirão para futura análise do secretoma de T. reesei RUT C-30. Em meio de lactose, os valores de atividades enzimáticas obtidos com 54 horas de cultivo foram: FPase (1,43 UI mL-1), CMCase (15,67 UI mL-1), xilanase (11,91 UI mL-1) e β-glicosidase (0,24 UI mL-1). A velocidade máxima específica de crescimento, μmax, e o coeficiente de rendimento de biomassa no substrato, Yx/s, foram 0,06 h-1 e 0,38 g g-1, respectivamente. Em meio de melaço, μmax e Yx/s foram 0,26 h-1 e 0,52 g g-1, respectivamente, e as atividades enzimáticas insignificantes. No hidrolisado, o crescimento do micro-organismo foi inibido devido à presença de compostos inibidores produzidos no tratamento hidrotérmico. Os valores de atividades enzimáticas com 54 horas foram: FPase (0,06 UI mL-1), CMCase (0,24 UI mL-1), xilanase (1,40 UI mL-1) e β-glicosidase nula. Em meio com celulose, também foram obtidos baixos valores de atividades enzimáticas, porém, a xilanase apresentou valor de 1,52 UI mL-1 com 50 horas de cultivo. A xilanase foi a enzima mais evidente nos cultivos com xilana, atingindo valor máximo de 11,93 UI mL-1, ao final do cultivo. Em meio com pectina: FPase, CMCase, xilanase e β-glicosidase foram: 0,01 UI mL-1, 1,25 UI mL-1, 2,83 UI mL-1 e 0,10 UI mL-1, respectivamente. Nos cultivos em meio à base de palma, observaram-se os seguintes valores com 50 horas: FPase (0,29 UI mL-1), CMCase (3,30 UI mL-1), xilanase (6,21 UI mL-1) e β-glicosidase (0,09 UI mL-1). Entre as fontes investigadas, a lactose é o melhor substrato para a indução de todas as enzimas estudadas, enquanto o melaço favorece o crescimento rápido do micro-organismo. O hidrolisado hemicelulósico e a palma forrageira são potenciais meios para a produção de enzimas, em particular xilanases. Para a utilização do hidrolisado, no entanto, será necessária a sua detoxificação ou, alternativamente, a obtenção de linhagens resistentes aos inibidores por engenharia metabólica e/ou engenharia evolutiva.