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1.
Braz. j. microbiol ; 46(1): 261-264, 05/2015. tab, graf
Artículo en Inglés | LILACS | ID: lil-748265

RESUMEN

The monoterpenoid 1,8-cineole is obtained from the leaves of Eucalyptus globulus and it has important biological activities. It is a cheap natural substrate because it is a by-product of the Eucalyptus cultivation for wood and pulp production. In this study, it was evaluated the potential of three filamentous fungi in the biotransformation of 1,8-cineole. The study was divided in two steps: first, reactions were carried out with 1,8-cineole at 1 g/L for 24 h; afterwards, reactions were carried out with substrate at 5 g/L for 5 days. The substrate was hydroxylated into 2-exo-hydroxy-1,8-cineole and 3-exo-hydroxy-1,8-cineole by fungi Mucor ramannianus and Aspergillus niger with high stereoselectivity. Trichoderma harzianum was also tested but no transformation was detected. M. ramannianus led to higher than 99% of conversion within 24 h with a starting high substrate concentration (1 g/L). When substrate was added at 5 g/L, only M. ramannianus was able to catalyze the reaction, but the conversion level was 21.7% after 5 days. Both products have defined stereochemistry and could be used as chiral synthons. Furthermore, biological activity has been described for 3-exo-hydroxy-1,8-cineol. To the best of our knowledge, this is the first report on the use of M. ramannianus in this reaction.


Asunto(s)
Aspergillus niger/metabolismo , Ciclohexanoles/metabolismo , Eucalyptus/química , Monoterpenos/metabolismo , Mucorales/metabolismo , Hidroxilación , Factores de Tiempo , Trichoderma/metabolismo
2.
Braz. j. microbiol ; 45(3): 929-932, July-Sept. 2014. ilus, tab
Artículo en Inglés | LILACS | ID: lil-727022

RESUMEN

The β-ketoester benzyl acetoacetate was enantioselectively reduced to benzyl (S)-3-hydroxybutanoate by seven microorganism species. The best result using free cells was obtained with the yeast Hansenula sp., which furnished 97% ee and 85% of conversion within 24 h. After immobilization in calcium alginate spheres, K.marxianus showed to be more stable after 2 cycles of reaction.


Asunto(s)
Acetoacetatos/metabolismo , Compuestos de Bencilo/metabolismo , Kluyveromyces/metabolismo , Pichia/metabolismo , Células Inmovilizadas/metabolismo , Oxidación-Reducción , Factores de Tiempo
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