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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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/15785 |
| Date | 26 February 2010 |
| Creators | Guedes, Rodrigo Caetano |
| Contributors | CPF:10847022404, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788057U7, Pedrini, M?rcia Regina da Silva, CPF:85203513953, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4797345U9, Santos, Sharline Florentino de Melo, CPF:88567109434, http://lattes.cnpq.br/4846443214585734, Santos, Everaldo Silvino dos, Macedo, Gorete Ribeiro de |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Engenharia Qu?mica, UFRN, BR, Pesquisa e Desenvolvimento de Tecnologias Regionais |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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