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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Produ??o de enzimas lignocelulol?ticas e de bioetanol a partir de res?duos da palha de carna?ba (Copernicia prunifera) pr?-tratados

Silva, Francinaldo Leite da 19 December 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-21T11:51:42Z No. of bitstreams: 1 FrancinaldoLeiteDaSilva_TESE.pdf: 3609009 bytes, checksum: 2c514bec8990f69a112dbf03fff72a30 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-23T12:33:28Z (GMT) No. of bitstreams: 1 FrancinaldoLeiteDaSilva_TESE.pdf: 3609009 bytes, checksum: 2c514bec8990f69a112dbf03fff72a30 (MD5) / Made available in DSpace on 2018-03-23T12:33:28Z (GMT). No. of bitstreams: 1 FrancinaldoLeiteDaSilva_TESE.pdf: 3609009 bytes, checksum: 2c514bec8990f69a112dbf03fff72a30 (MD5) Previous issue date: 2017-12-19 / Nativa do Brasil, a Carna?ba (Copernicia prunifera) tem sido utilizada para diversos fins, incluindo a produ??o de cera a partir de suas folhas, cujo processo gera uma quantidade consider?vel de res?duo, o qual se caracteriza como uma fibra rica em celulose e, portanto, com um potencial para uso como fonte de carbono para a produ??o de enzimas celulol?ticas e etanol. A estrutura qu?mica desse material apresenta a celulose ligada a componentes estruturalmente complexos, como a hemicelulose e a lignina, o que dificulta a produ??o das celulases por fungos filamentosos, bem como, a sua hidr?lise enzim?tica, sendo imprescind?vel a utiliza??o de um pr?-tratamento para a viabiliza??o desses processos. O presente estudo avaliou o efeito de diferentes pr?-tratamentos na palha de carna?ba para a produ??o de enzimas lignocelulol?ticas e para a hidr?lise enzim?tica com vistas ? produ??o de etanol celul?sico por meio dos conceitos de biorrefinaria e microdestilaria. Na primeira etapa deste trabalho, o res?duo da palha de carna?ba foi submetido aos pr?-tratamentos hidrot?rmico (HT), alcalino (AL), ?cido alcalino (AA) e per?xido de hidrog?nio alcalino (A-HP). Os res?duos pr?-tratados e n?o tratado foram caracterizados quimicamente conforme o protocolo da National Renewable Energy Laboratory (NREL) e, fisicamente, por meio das an?lises de Microscopia Eletr?nica de Varredura (MEV), Difra??o de Raio X (DRX) e Espectroscopia de Infravermelho Transformada de Fourier (FTIR). Uma parte de cada res?duo foi utilizada para produ??o de enzimas por meio de Fermenta??o em Estado S?lido (FES), utilizando o fungo Trichoderma reesei CCT-2768. As atividades FPAse, CMCase, ?-glicosidase e xilanase dos extratos foram estimadas e a produ??o posteriormente otimizada. A outra parte dos res?duos foi submetida ? Sacarifica??o e Simult?nea Fermenta??o (SSF) com enzimas comerciais, utilizando as leveduras Saccharomyces cerevisiae UFLA CA11, Saccharomyces cerevisiae CAT-1 e Kluyveromyces marxianus ATCC-36907. Os resultados dos pr?-tratamentos AL, AA e A-HP se destacaram em termos de remo??o de lignina, segundo as an?lises qu?mica e f?sica dos res?duos. Os estudos evidenciaram que o pr?-tratamento da palha da carna?ba com A-HP possui maior capacidade de indu??o da produ??o de enzimas lignocelulol?ticas ao se comparar com outros res?duos lignocelul?sicos, como coco, caju e cana-de-a??car, pr?-tratados pelo mesmo m?todo. A otimiza??o da produ??o de enzimas lignocelulol?ticas permitiu a produ??o de um extrato enzim?tico com atividade FPase de 2,4 U/g e xilanases de 172 U/g. A aplica??o do extrato enzim?tico na hidr?lise do baga?o de cana-de-a??car pr?-tratado mostrou efici?ncia de 86,96%. A hidr?lise enzim?tica, com enzimas comerciais, do res?duo da carna?ba submetido ao pr?-tratamento AL, apresentou a maior convers?o de a??cares (64,43%) e, ao ser submetido ? SSF, produziu 7,53 g/L de etanol, usando Kluyveromyces marxianus ATCC-36907 cultivada a 45 ?C. Os resultados evidenciam, portanto, o potencial biotecnol?gico do res?duo da carna?ba para a produ??o de enzimas celulol?ticas e na obten??o de bioetanol em um arranjo de biorrefinaria e microdestilaria. / Native to Brazil, Carnauba (Copernicia prunifera) has been used for several purposes, including the wax production from its leaves, in the process that generates a considerable amount of residue. This residue is characterized as a fiber rich in cellulose and therefore with potential latent for use as a source of carbon for the production of cellulolytic enzymes and bioethanol. However, the chemical structure of this material presents cellulose bound to structurally complex components, such as hemicellulose and lignin, which hinders the production of cellulases by filamentous fungi, as well as its enzymatic hydrolysis, being essential to use of a pre-treatment for the viability of these processes. The present study evaluated the effect of different pre-treatments on carnauba straw for the production of lignocellulolytic enzymes and for the enzymatic hydrolysis with a view to the production of cellulosic ethanol through the concepts of biorefinery and micro-distillery. In the first stage, carnauba straw residue was submitted to hydrothermal (HT), alkaline (AL), alkaline acid (AA) and alkaline hydrogen peroxide (A-HP) pre-treatments. The pretreated and untreated residues were chemically characterized according to the National Renewable Energy Laboratory (NREL) protocol and, physically, by Scanning Electron Microscopy (MEV), X-Ray Diffraction (XRD) and Spectroscopy of Infrared by Fourier Transform (FTIR). A part of each residue was used to produce enzymes by means of Solid State Fermentation (FES), using the fungus Trichoderma reesei CCT-2768. The FPAse, CMCase, ?-glycosidase and xylanase activities of the extracts were estimated and the production was subsequently optimized. The other part of the residues was subjected to Saccharification and Simultaneous Fermentation (SSF) using commercial enzymes and Saccharomyces cerevisiae UFLA CA11, Saccharomyces cerevisiae CAT-1 and Kluyveromyces marxianus ATCC-36907. The results of the pretreatments AL, AA and A-HP stood out in terms of the removal of lignin, according to the chemical and physical analysis of the residues. The studies showed that pretreatment of carnauba straw with A-HP has a higher capacity to induce the production of lignocellulolytic enzymes when compared to other residues, such as coconut, cashew apple and sugar cane, pretreated by the same method. The optimization of the production of lignocellulolytic enzymes allowed the production of an enzymatic extract with FPase activity of 2.4 U/g and xylanases of 172 U/g. The application of the enzymatic extract in the hydrolysis of pretreated sugarcane bagasse showed efficiency of 86.96%. The use of AL pretreated carnauba residue in enzymatic hydrolysis, with commercial enzymes, showed a higher conversion of sugars (64.43%) and, when submitted to SSF, produced 7.53 g/L of ethanol, using Kluyveromyces marxianus ATCC-36907 cultured at 45 ?C. The results showed, therefore, the biotechnological potential of the carnauba residue for the production of cellulolytic enzymes and the production of bioethanol by means of biorefinery and micro distillery.
2

Estudo da influ?ncia de pr?-tratamentos de dois res?duos lignocelul?sicos (baga?o do ped?nculo de caju e casca de coco) utilizados como substrato na indu??o ? s?ntese de enzimas celulol?ticas

Guedes, Rodrigo Caetano 26 February 2010 (has links)
Made available in DSpace on 2014-12-17T15:01:21Z (GMT). No. of bitstreams: 1 RodrigoCG_DISSERT_2010.pdf: 836774 bytes, checksum: 86ff894110e71c4fda4b7950daeb0674 (MD5) Previous issue date: 2010-02-26 / Nowadays generation ethanol second, that t is obtained from fermentation of sugars of hydrolyses of cellulose, is gaining attention worldwide as a viable alternative to petroleum mainly for being a renewable resource. The increase of first generation ethanol production i.e. that obtained from sugar-cane molasses could lead to a reduction of lands sustainable for crops and food production. However, second generation ethanol needs technologic pathway for reduce the bottlenecks as production of enzymes to hydrolysis the cellulose to glucose i.e. the cellulases as well as the development of efficient biomass pretreatment and of low-cost. In this work Trichoderma reesei ATCC 2768 was cultivated under submerged fermentation to produce cellulases using as substrates waste of lignocellulosic material such as cashew apple bagasse as well as coconut bagasse with and without pretreatment. For pretreatment the bagasses were treated with 1 M NaOH and by explosion at high pressure. Enzyme production was carried out in shaker (temperature of 27?C, 150 rpm and initial medium pH of 4.8). Results showed that T.reesei ATCC 2768 showed the higher cellulase production when the cashew apple bagasse was treated with 1M NaOH (2.160 UI/mL of CMCase and 0.215 UI/mL of FPase), in which the conversion of cellulose, in terms of total reducing sugars, was of 98.38%, when compared to pretreatment by explosion at high pressure (0.853 UI/mL of CMCase and 0.172 UI/mL of Fpase) showing a conversion of 47.39% of total reducing sugars. Cellulase production is lower for the medium containing coconut bagasse treated with 1M NaOH (0.480 UI/mL of CMcase and 0.073 UI/mL of FPase), giving a conversion of 49.5% in terms of total reducing sugars. Cashew apple bagasse without pretreatment showed cellulase activities lower (0.535 UI/mL of CMCase and 0,152 UI/mL of FPase) then pretreated bagasse while the coconut bagasse without pretreatment did not show any enzymatic activity. Maximum cell concentration was obtained using cashew nut bagasse as well as coconut shell bagasse treated with 1M NaOH, with 2.92 g/L and 1.97 g/L, respectively. These were higher than for the experiments in which the substrates were treated by explosion at high pressure, 1.93 g/L and 1.17 g/L. Cashew apple is a potential inducer for cellulolytic enzymes synthysis showing better results than coconut bagasse. Pretreatment improves the process for the cellulolytic enzyme production / Recentemente o etanol de segunda gera??o, obtido da fermenta??o dos hidrolisados de celulose, vem despertando a aten??o mundial por ser uma alternativa vi?vel e ambientalmente correta ao petr?leo, uma vez que aumentar a produ??o de etanol a partir do mela?o da cana-de-a??car, o etanol de primeira gera??o, implicaria na utiliza??o de terras destinadas a produ??o de alimentos. Entretanto, o etanol de celulose exige rotas tecnol?gicas que ainda o tornam pouco competitivo, como a produ??o de enzimas que quebrem a celulose em glicose, as celulases, e a ado??o de um processo de pr?-tratamento eficiente e de baixo custo capaz de diminuir o grau de intera??o que existe nas fibras vegetais. No presente trabalho, Trichoderma reesei ATCC 2768 foi cultivada em meio submerso para produ??o de celulases utilizando como substratos res?duos lignocelul?sicos, baga?o do ped?nculo de caju e baga?o de coco, sem tratamento e tratados com NaOH 1M e por explos?o a alta press?o. Os experimentos de produ??o das enzimas foram realizados em meio submerso e conduzidos em incubador rotat?rio (temperatura de 27?C, velocidade de agita??o de 150 rpm e pH inicial do meio de 4,8). Os resultados mostraram que T. reesei ATCC 2768 apresentou maior produ??o de celulases em meio contendo baga?o do ped?nculo de caju tratado com NaOH 1M (2,160 UI/mL de CMCase e 0,215 UI/mL de FPase), onde o consumo de celulose em forma de a??cares redutores totais foi de 98,38%, quando comparado com o mesmo tratado por explos?o a alta press?o (0,853 UI/mL de CMCase e 0,172 UI/mL de Fpase), apresentando um consumo de 47,39% de ART s. Os resultados mostraram ainda que a produ??o de celulase ? menor em meio contendo baga?o de coco tratado com NaOH 1M (0,480 UI/mL de CMcase e 0,073 UI/mL de FPase), chegando-se a 49,5% de ART s consumidos. O baga?o do ped?nculo de caju sem tratamento apresentou uma atividade bem inferior (0,535 UI/mL de CMCase e 0,152 UI/mL de FPase) quando comparado aos baga?os com tratamento e o baga?o de coco n?o-tratado n?o apresentou atividade enzim?tica. A concentra??o m?xima de c?lulas foi maior quando se utilizou como substrato os baga?os do ped?nculo de caju e casca de coco tratados alcalinamente, 2,92 g/L e 1,97 g/L, respectivamente, do que aqueles tratados por explos?o a alta press?o, 1,93 g/L e 1,17 g/L. Conclui-se que o ped?nculo de caju ? um potencial indutor ? s?ntese de enzimas celulol?ticas, apresentando-se melhor que o baga?o de coco bem como o tratamento melhora bastante o processo de s?ntese das enzimas.

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