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Master's Dissertation
DOI
https://doi.org/10.11606/D.11.2019.tde-20191218-155802
Document
Author
Full name
Rosilene Naves Domingos
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 1996
Supervisor
Title in Portuguese
Acúmulo de cádmio por Saccharomyces cerevisiae fermentando mosto de melaço
Keywords in Portuguese
CÁDMIO
FERMENTAÇÃO ALCOÓLICA
LEVEDURAS
MOSTO DE MELAÇO
Abstract in Portuguese
O presente trabalho visou o estudo do acúmulo e, eventual, concentração de cádmio (Cd) por Saccharomyces cerevisiae, fermentando mosto de melaço, com contaminações controladas, em níveis sub-tóxicos do citado metal (mg Cd/kg mosto). O cádmio foi o metal pesado escolhido devido à sua toxidez, e recente penetração no ambiente, como conseqüência do desenvolvimento tecnológico. Realizou-se análises do melaço quanto a determinação de Açúcares Redutores Totais (ART), Açúcares Redutores (AR), e dos elementos P, K, Ca, Mg, Zn, Cu, Mn, Fe, B e S, como também, análise do cádmio, por espectrofotometria de absorção atômica. As condições de fermentação foram as reinantes na produção industrial de etanol. O mosto, não esterilizado, continha 12% ART (p/p), pH 4,5 e nutrientes a base de nitrogênio, fósforo, potássio e magnésio. Para a contaminação controlada empregou-se dois sais de cádmio, cloreto (CdCl 2.2 1/2H2O)e, acetato (CdC4H6O4.2H2O, com propriedades diferentes e quatro níveis de contaminações (05; 1,0; 2,0; 5,0 mg Cd/Kg mosto). A inoculação do mosto foi efetuada com fermento de panificação (10% p/p). Terminada a fermentação colheu-se amostras para determinação da viabilidade celular e porcentagem de fermento. O vinho foi centrifugado e procedeu-se às análises do mesmo e da levedura bruta. Mediu-se volume do vinho delevurado; a porcentagem de levedura; e o teor alcoólico, após destilação. Na levedura determinou-se peso úmido total; matéria-seca; proteína bruta, e cádmio por espectroscopia de absorção atômica. Observou-se que em todos os níveis estudados houve acumulação de cádmio pela levedura
Title in English
Acumulation of heavy metal by Saccharomyces cerevisiae fermenting wort of molasses
Abstract in English
The aim of this paper is to study the absorption and probable cadmium (Cd) casual concentration by Saccharomyces cerevisiae, fermenting wort of molasses, with controI contamination, under toxic leveIs of cadmium (mg Cd/kg must). Cadmium was chosen because of its toxicity, and recent penetration in the environment, as a consequence of the technological deveIopment. Analyses were carried out such as raw-material (molasses), total reducing sugar, reducing sugar, and elements such as P, K, Ca, Mg, Zn, Cu, Mn, Fe, B and S as well as the heavy metal analysis. Fermentation conditions were the same ones for alcohol industrial production. Non-sterelized wort showed 12% of total reducing sugar (w/w), pH 4,5 and nutrients of nitrogen, phosphorus, kalium and magnesium. For the control contamination, two saIts of cadmium were applied, chloride CdCl 2.2 1/2H2O)and acetate (CdC4H6O4.2H2O), with different properties and four leveIs of contamination: 0,5; 1,0; 2,0 and 5,0 mg Cd/kg wort. The inoculation of wort was carried out with bread yeast (10%w/w). After fermentation, samples were selected to evaluate cellular viability and yeast percentage. Wine was centrifuged and analyses of wine without yeast and raw yeast were performed. The wine volume with out yeast, was measured in a beaker, the yeast percentage in a centrifuge and the alcohol content in a digital densimeter after distilation. An analytical balance was used to determine t heavy metal by atomic absorption spectroscopy. Watch all leveI studed haved accumulation of cadmium at yeast.
 
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Publishing Date
2019-12-19
 
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