Estudo sobre utilização de crisotila como suporte de celulas de saccharomyces cerevisiae para uso em processo continuo de fermentação alcoolica e biorreduções

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

The possibility of using chrysotile asbestos fibers as a carrier for pure strains cells of Saccharomyces cerevisiae and Baker s yeast immobilization was investigated. The fonned chrysotile/cells complex was experimented in continuous process for alcoholic fennentation and asymmetric reduction of ketones. The alcohoIic fermentation in batch operation using baker s yeast cells showed 25 to 30% higher production of ethanol with immobilized cells, compared with the same conditions using non immobilized cells. In a continuous operation, a packed bed reactor filled with baker s yeast cells/chrysotile complex mixed with sand (f = 0,3 cm) was feed continuously with an ascendant flow of a 20% sucrose solution. A maximum productivity of 16 g.L.h was obtained at a specific dilution rate of 3,8 x 10 h. A good leveI of operational stabiIity was observed during 30 days. A reactor with the same type as described above to alcoholic fermentation was used to perform bioreduction of ketones. The reactor was feed continuously with an ascendant flow of a steriIized solution of carbonylic compounds (0,33 - 0,66 g/L ) and cell nutrients, using a mixture of water/ethanol (9: 1) as solvent. Under a constant dilution rate of 1,65 x 10 h, the steady state showed average values... of 2.9 x 10 g. L. h of productivity, 50% chemical yield, and / enantiomeric excess >90%. The operational stability related to chemical yield and enantiomeric excess was kept for at least 30 days. Specific strains of Saccharomyces cerevisiae (CCT0762 and FEA01) were used to the continuous alcoholic fermentation with molasses solution to test the possibility of using these process in a industrial application. A maximum productivity of 28 g.L.h was obtained. These value is two times higher than using baker s yeast with sucrose solution. The operational stability were kept during 27 days between 15 to 20 g.L.h.

ASSUNTO(S)

celulas imobilizadas

ACESSO AO ARTIGO

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