Biocatalytic ketone reduction—a powerful tool for the production of chiral alcohols—part II: whole-cell reductions

Abstract

Enzymes are able to perform reactions under mild conditions, e.g., pH and temperature, with remarkable chemo-, regio-, and stereoselectivity. Due to this feature the number of biocatalysts used in organic synthesis has rapidly increased during the last decades, especially for the production of chiral compounds. The present review highlights biotechnological processes for the production of chiral alcohols by reducing prochiral ketones with whole cells. Microbial transformations feature different characteristics in comparison to isolated enzymes. Enzymes that are used in whole-cell biotransformations are often more stable due to the presence of their natural environment inside the cell. Because reductase-catalyzed reactions are dependent on cofactors, one major task in process development is to provide an effective method for regeneration of the consumed cofactors. Many whole-cell biocatalysts offer their internal cofactor regeneration that can be used by adding cosubstrates, glucose or, in the case of cyanobacteria, simply light. In this paper, various processes carried out on laboratory and industrial scales are presented. Thereby, attention is turned to process parameters, e.g., conversion, yield, enantiomeric excess, and process strategies, e.g., the application of biphasic systems. The biocatalytic production of chiral alcohols utilizing isolated enzymes is presented in part I of this review.

Chiral pesticides

“…106) Recently, the biocatalytic production of chiral alcohols utilizing isolated enzymes and whole cells has been reported. [107][108] …”

Production of Valuable Lipophilic Compounds by Using Three Types of Interface Bioprocesses: Solid–Liquid Interface Bioreactor, Liquid–Liquid Interface Bioreactor, and Extractive Liquid-Surface Immobilization System

“…The reductase enzyme of microorganisms is a versatile and useful enzyme for preparing chiral alcohols by asymmetric reduction 58 . S/L-IBR has been used for reducing -preferentially reduce EOPB to R -EHPB in an n-decane layer.…”

Asymmetric reduction of ketones with recombinant E. coli whole cells in neat substrates

“…3,4 On the other hand, process stability of biocatalysts can be increased and costs for catalysts and cofactors can be reduced by the use of whole cells rather than isolated enzymes. 5,6 For the industrial performance of the asymmetric reduction of prochiral ketones by alcohol dehydrogenases the demand for expensive nicotinamide cofactors plays a particular role in cell-free systems. 7 Hence, the use of whole cells exhibits as a major advantage that cofactors can be intrinsically recycled via the coupling of a second substrate or by a second enzyme.…”