Enantioselective microbial reduction with baker's yeast on an industrial scale

Microbial synthesis is an important contribution to Green Chemistry and production-integrated environmental protection. The example of baker's yeast is used to demonstrate how microorganisms can be versatile reagents for asymmetric synthesis and how microbial technologies can be alternatives and complements to catalytic processes. The commercial viability of enantioselective microbial processes on an industrial scale is shown with the examples of (S)-3-hydroxybutyric acid ethylester (1), (2S,5S)-hexanediol (2) and (1R,2S)-cis-2-hydroxycyclohexane carboxylic acid ethylester (3). The investigation of several competing enzymatic pathways in the living cells during the reduction reaction allows the process to be controlled and makes this technology applicable for the large-scale commercial synthesis of 3.