Fermento biologico de padaria (Saccharomyces cerevisiae) : aspectos bioquimicos e morfologicos e a inflencia deles em sintese organica assimetrica

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

Baker s yeast is becoming an important reagent for organic synthesis. However, in many occasions, there are problems with the experimental reproducibility which in general are due to the different origins of baker s yeasts. ln order to explain these differences, NAD(P) reduction inside intact living cells from different strains were measured. The method can select cells with better reduction power in a short period of time. The variation in the production of NAD(P)H in the interior of these living cells with external factors such as temperature and pH was measured. The results show that Japanese and Dutch strains are sensible to these factors and Brazilian strains are not. Another aspect studied was the effect of compounds known to inhibit some dehydrogenases and their effects on NAD(P)H prodution and the possible mechanism of action of them. The measuring of NAD(P)H is a good method to identify one type of cell more adequate to use in biatransformations getting a result more reproducible. The strains of baker s yeast were imaged with an atomic force microscope (AFM). The images of uncoated and non-fixed samples were reproducible with high-constrast and nanometer-resolution. Molecules from the polysaccharide surface of the cell wall were pictured and the distance of atoms was measured. The preparation of samples was easy, suggesting that AFM is an useful tool in these type of analysis.

ASSUNTO(S)

microscopia de força atomica saccharomyces cerevisiae sintese organica assimetrica

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