Bioreduction of Some Common Carbonylic Compounds Mediated by Yeasts

Abstract

Bioreduction of several prochiral carbonylic compounds such as acetophenone (1), ethyl acetoacetate (2) and ethyl phenylpropionate (3) to the corresponding optically active secalcohols 1a -3a was performed using wild-type strains of Pichia pastoris UBB 1500, Rhodotorula sp., and Saccharomyces cerevisiae. The reductions showed moderate to excellent conversion and high enantiomeric excess, in an extremely mild and environmentally benign manner in aqueous medium, using glucose as cofactor regeneration system. The obtained alcohols follow Prelog's rule, but in the reduction of 1 with P. pastoris UBB 1500 the antiPrelog enantiopreference was observed.

Production of Chiral (S)-2-Phenyl-1-Propanol by Enantioselective Biocatalysts

“…Wholecell biocatalysts ensure the optimal environment for the enzyme, thereby providing a quite stable system. Furthermore, they contain cofactors and are able to bring about cofactor regeneration without the necessary addition of any other compounds [6]. However, the presence of a variety of enzymes may lead to side reactions.…”

“…Over recent decades, both wild and genetically modified strains of yeast have been gaining more and more attention as biocatalysts in the production of fine chemicals [7]. Although (S)-alcohol is generally the predominant enantiomer in the reduction of racemic carboxylic acid compounds by applying yeast [6], this is dependent on the given substrate [9]. Our second catalyst was recombinant horse-liver ADH expressed in E. coli.…”

Yeast‐Mediated Stereoselective Synthesis

“…Albeit there are many reports on the reduction of steroidal cycloalkanones [15,[129][130][131][132] and their precursors [133] by yeast (or rather often by bacterial contaminants of the yeast), less examples are known for the reduction of simple cycloalkanones [94,[134][135][136]. Addition of extra yeast nutrient and riboflavin to the reaction mixture allowed the smooth reduction of racemic 12 (Figure 21.8).…”