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. JÃ 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 Â 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.
| Identifer | oai:union.ndltd.org:IBICT/oai:www.teses.ufc.br:2121 |
| Date | 09 February 2007 |
| Creators | Maria Valderez Ponte Rocha |
| Contributors | Luciana Rocha Barros GonÃalves, Gustavo Adolfo Saavedra Pinto, Antonio Josà GonÃalves da Cruz, Maria Estela Aparecida Giro |
| Publisher | Universidade Federal do CearÃ, Programa de PÃs-GraduaÃÃo em Engenharia QuÃmica, UFC, BR |
| 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:Biblioteca Digital de Teses e Dissertações da UFC, instname:Universidade Federal do Ceará, instacron:UFC |
| Rights | info:eu-repo/semantics/openAccess |
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