Enhanced asymmetric reduction of ethyl 3-oxobutyrate by baker's yeast via substrate feeding and enzyme inhibition

K. L. Fow, L. C.H. Poon, S. T. Sim, G. K. Chuah, S. Jaenicke

Research output: Journal PublicationArticlepeer-review

8 Citations (Scopus)

Abstract

The moderate enantioselectivity of wild form baker's yeast can be considerably increased either by using continuous feeding to maintain a low substrate concentration throughout the reaction, or by the selective inhibition of competing enzymatic pathways. The reduction of ethyl 3-oxobutyrate to ethyl (S)-3-hydroxy-butyrate was used as a model reaction. With the substrate feeding method, the enantioselectivity could be increased from 75% to as high as 98%. The increased selectivity originates from the much higher substrate binding constant of the (R)-specific enzymes, so that these enzymes remain essentially inactive if a low concentration of ethyl 3-oxobutyrate is maintained in the bioreactor. Alternatively, the enantioselectivity of baker's yeast can be improved by selectively blocking competing enzymatic pathways. It was found that vinyl acetate is a selective inhibitor for the (R)-specific enzymes. Ethyl (S)-3-hydroxybutyrate with an enantiomeric excess of 98% was obtained by pre-incubation of baker's yeast in 100 mM of vinyl acetate solution for 1 h. These results suggest that by selecting appropriate process conditions, natural baker's yeast can be a competitive biocatalyst for the large-scale production of chiral secondary alcohols.

Original languageEnglish
Pages (from-to)372-380
Number of pages9
JournalEngineering in Life Sciences
Volume8
Issue number4
DOIs
Publication statusPublished - Aug 2008
Externally publishedYes

Keywords

  • (S)-3-hydroxybutyrate
  • Asymmetric synthesis
  • Baker's yeast
  • Enzyme inhibitor

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Environmental Engineering

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