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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

ProduÃÃo de biossurfactantes a partir da glicerina obtida da produÃÃo de biodiesel / Production of biosurfactants from glycerin obtained from biodiesel production

Juliana Rabelo de Sousa 28 February 2008 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O objetivo deste trabalho foi avaliar a glicerina resultante da transesterificaÃÃo do Ãleo de mamona como fonte de carbono e nutrientes para P. aeruginosa LAMI. O efeito da concentraÃÃo de nutrientes e de condiÃÃes ambientais foi avaliado de acordo com dois planejamentos fatoriais completos sobre o crescimento celular, produÃÃo de biossurfactante e propriedades tensoativas do surfactante produzido. A anÃlise estatÃstica dos dados foi realizada pelo software Statistica 6.0. Avaliou-se o efeito da concentraÃÃo de glicerina e de nitrato de sÃdio e do tamanho do inÃculo, de acordo com um planejamento fatorial 23. Uma anÃlise dos efeitos mostrou que o aumento da concentraÃÃo de nitrato e a reduÃÃo da concentraÃÃo de glicerina favoreceram a produÃÃo de biossurfactantes atingindo-se uma concentraÃÃo mÃxima de 1,6 g/L de ramnose. A partir deste resultado, realizou-se um planejamento fatorial completo 24 avaliando-se os fatores concentraÃÃo de nitrato e de fosfato, pH e temperatura. Os resultados mostraram que a reduÃÃo da razÃo carbono/nitrogÃnio (C/N), com um Ãtimo equivalente a 12, favoreceu a produÃÃo de ramnolipÃdeos por P. aeruginosa LAMI, bem como a reduÃÃo da concentraÃÃo de fosfato em pH 7,0 e temperatura de 37 ÂC. Nestas condiÃÃes obteve-se 2,3 g/L de ramnose, atingindo-se coeficientes de rendimento em termos de substrato (YP/S) e de biomassa (YP/X) de 0,103 g/g e 3,13 g/g,respectivamente. A produtividade volumÃtrica mÃxima foi 31,94 mg/Lh. A cinÃtica de crescimento celular e produÃÃo de biossurfactantes foi avaliada, variando-se a razÃo C/N de 21 a 86. Os perfis de produÃÃo de biomassa e de ramnolipÃdeos sugeriram uma cinÃtica mista, semiassociada ao crescimento. O biossurfactante obtido de acordo com a melhor condiÃÃo de cultivo foi capaz de formar emulsÃes com querosene, Ãleo de soja, Ãster metÃlico e Ãleo naftÃnico, com Ãndice de emulsificaÃÃo de, aproximadamente, 60 %. Uma atividade emulsificante equivalente a 3,25 unidades mostrou que o biossurfactante foi capaz de formar emulsÃes Ãleo-Ãgua. O biossurfactante foi extraÃdo do meio de cultivo livre de cÃlulas e submetido a purificaÃÃo por cromatografia. A cromatografia em camada delgada mostrou a presenÃa de dois produtos majoritÃrios. O espectro de ressonÃncia magnÃtica nuclear H1 apresentou deslocamentos quÃmicos caracterÃsticos de grupamentos quÃmicos que constituem uma molÃcula de diramnolipÃdeo tipo Rha-Rha-C10C10. Entretanto, a elucidaÃÃo completa da estrutura do ramnolipÃdeo deve ser complementada por anÃlises espectroscÃpicas de maior resoluÃÃo / The aim of this work was analysing the glycerine from castor oil transesterification as a source of carbon and nutrients to P. aeruginosa LAMI. Nutrients concentration and environmental conditions were studied using two complete factorial planning, with cellular growth, biosurfactant production and product surface active properties as response variables. The statistic analysis was done using the software Statistica 6.0. First of all, inoculum size and concentrations of glycerine and NaNO3 were analysed with a 23 factorial planning. The increase in nitrate concentration and a decrease in glycerine concentration favored biosurfactants production, reaching a maximum rhamnose concentration of 1.6 g/L. A complete 24 factorial planning was planned based on these results. Nitrate and phosphate concentrations, pH and temperature were selected factors. Results showed that a decrease in carbon/nitrogen ratio, with an optimum of 12, and phosphate concentration favored rhamnolipid production by P. aeruginosa LAMI at pH 7,0 and 37 ÂC. A rhamnose concentration of 2.3 g/l was obtained, with product yields on substrate and biomass of 0.103 and 3.13g/g,respectively. The volumetric productivity was 31.94 mg/L.h. The influence of carbon/nitrogen ration, from 21 to 86, on growth kinetics and biosurfactant production was studied. Biomass and rhamnolipids production behavior suggest a mixed kinetics, semi-associated to growth. The biosurfactant produced using the optimized conditions formed emulsions with kerosene, soybean oil, methyl esters (biodiesel) and naphtenic oil, with emulsification index of about 60%. An emulsification activity of 3.25 units was also obtained, showing that the biosurfactant may be used to forme oil-water emulsions. Finally, the biosurfactant was extracted from a free-cell fermented medium and submited to chromatographic purification. The analytical thin layer chromatography showed the presence of two mainly products. The H1 nuclear magnetic spectra showed characteristic signals of chemical groups that are typical of a dirhamnolipid Rha-Rha-C10C10 molecule. However, a complete explanation of the rhamnolipid structure must be completed by high resolution spectroscopy analysis
2

ProduÃÃo de Biossurfactantes por FermentaÃÃo Submersa usando Substrato NÃo Convencional / Biosurfactants Production by Batch Fermentation using Alternative Substrate

Maria Valderez Ponte Rocha 09 February 2007 (has links)
AgÃncia Nacional do PetrÃleo / Este trabalho teve como objetivo avaliar a produÃÃo de biossurfactante por cepas de Pseudomona aeruginosa e Bacillus subtilis, utilizando suco de caju, integral e clarificado, como matÃria-prima nÃo convencional. Nos ensaios com P. aeruginosa ATCC 10145 em mesa agitadora, avaliou-se a suplementaÃÃo do suco de caju integral (CAJN) com Ãleo de soja, como fonte de carbono, e com diferentes fontes de nitrogÃnio: peptona, NaNO3 e (NH4)2SO4, sendo estes resultados comparados com os obtidos utilizando caldo nutritivo e com meio CAJN. A maior reduÃÃo na tensÃo superficial (41 %) foi obtida no suco de caju suplementado com peptona (CAJP) apÃs 24 h de cultivo. Neste ensaio, observou-se uma reduÃÃo da tensÃo superficial do meio de 50 para 29,5 dina cm-1. Jà em meio suplementado com NaNO3 e (NH4)2SO4, obteve-se, respectivamente, uma reduÃÃo na TS de 37,14 e 15,85% apÃs 72 horas de cultivo. Estudou-se a suplementaÃÃo do meio CAJP com glicerol e Ãleo de soja. Nestes ensaios, observou-se um alto crescimento celular, obtendo uma densidade Ãptica (a 600nm) de 5,0 com 48 h de cultivo, contudo uma pequena reduÃÃo da tensÃo superficial (16,51 %) ao utilizar glicerol. Com base nos resultados conduzidos em mesa agitadora, os meios CAJP e CAJNaNO3 foram selecionados para estudos em fermentador de bancada. Realizaram-se ensaios utilizando biorreator a 30ÂC, 200 rpm e sem aeraÃÃo, porÃm nÃo se observou o mesmo perfil de produÃÃo de ramnolipÃdeos ocorrido em mesa agitadora. Tal fato pode ter ocorrido devido à falta de oxigÃnio no meio de cultivo. Acompanhou-se a estabilidade tÃrmica, efeito da variaÃÃo de pH e da concentraÃÃo de NaCl, na atividade emulsificante do biossurfactante produzido em CAJP e sua composiÃÃo quÃmica. O biossurfactante produzido por P. aeruginosa demonstrou-se estÃvel a variaÃÃes de temperatura, pH e concentraÃÃes de NaCl, e emulsionou todos os hidrocarbonetos estudados e Ãleo de soja. Em paralelo, diferentes ensaios foram realizados visando otimizar o meio de cultivo para a produÃÃo de surfactina por B. subtilis usando CAJN e suco de caju clarificado (CAJC). Os melhores resultados foram obtidos quando se utilizou meio mineral suplementado com extrato de levedura e formulado com CAJC, de maneira que a concentraÃÃo de glicose fosse de 10 g.L-1. Nestes ensaios, obteve-se uma reduÃÃo de 21,37 % na tensÃo superficial e observou-se a presenÃa de surfactina atravÃs das anÃlises conduzidos em HPLC. No entanto, a mÃnima tensÃo superficial alcanÃada foi superior a 39 dina.cm-1. Portanto, avaliaram-se outras cepas de B. subtilis, doze ao total, quanto à capacidade de produzir surfactina utilizando CAJC. ApÃs 48 horas de cultivo com as cepas BE 08, a tensÃo superficial do meio de cultivo livre de cÃlulas atingiu 28,0  1,0 dina.cm-1, que tambÃm apresentou atividade emulsificante. Os resultados obtidos neste trabalho indicam que o suco de caju à uma matÃria-prima adequada para a produÃÃo de biossurfactantes. / The aim of this work was to investigate the use of natural and clarified cashew apple juice as an alternative raw material for biosurfactant production by Pseudomonas aeruginosa and Bacillus subtilis. In the assays with P. aeruginosa ATCC 10145 on rotary shaker, the influence of medium (CAJN) supplementation with soybean oil, as source carbon, and with different sources of nitrogen: peptone, NaNO3 and (NH4)2SO4, were investigated. Results were compared with the obtained when Nutritive Broth (NB) and CAJN were used as culture medium. Maximum reduction in the Surface Tension (41%)was obtained when P. aeruginosa was grown on CAJP, after 24 h of cultive. In these assays, the surface tension was reduced from 50 to 29.5 dina.cm-1. When P. aeruginosa was grown on CAJN supplemented with NaNO3 or (NH4)2SO4, the reduction in the Surface Tension was of 37.14 and 15.85 %, respectively, after 72 h of cultive. Evaluated CAJP supplemented with glycerol and soybean oil. In these assays, high growth was observed, an optical density of 5,0 at 600 nm with 48h of culture was observed, however small reduction in surface tension (16,51 %) was achieved using glycerol as carbon source. Based on the results in flasks, the mediums CAJP and CAJNaNO3 were selected for further studies in a biorreator. The assays were conduced in biorreator at 30ÂC, 200 rpm and without aeration. Nevertheless, the expected profile of rhamnolipids production was not observed. Such fact may have happened due to the lack of oxygen in the cultivation medium, since the process was conducted without aeration. The stability of biosurfactant produced by P. aeruginosa in CAJP against NaCl, pH and temperature and its chemical structure were evaluated. The biosurfactante produced by P. aeruginosa was stable to temperature and variations, as well as against different NaCl concentrations. Furthermore, it emulsified all the studied hydrocarbons and soybean oil. No protein was detected in the extracted biosurfactant; it however contained carbohydrate. The highest biosurfactant production occurred with 48h,when CAJP was used as culture medium (3.86 g of biosurfactant for 1000 mL de medium) and the poorest in NB. In parallel, different assays were performed to optimize the culture media for surfactin production by Bacillus subtilis using CAJN and clarified cashew apple juice (CAJC). Best results were obtained when mineral medium supplemented with yeast extract (5 g.L-1) was used and formulated with CAJC (glucose concentration - 10 g.L-1). In these assays, a reduction of 21.37 % in the surface tension was obtained and production of surfactin was observed by HPLC. However, best results of surface tension were higher than 39 dina.cm-1. Therefore, twelve strains of Bacillus sp. were evaluated regarding the ability of producing surfactin when grown on CAJC. After 48 hours of cultivation, with strain BE 08, the surface tension of the fermented broth, free of cells, reached 28.0  1.0 dina.cm-1,and it also presented emulsifying activity. The results obtained in this work indicate that the cashew apple juice is an appropriate raw material for biosurfactants production.

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