Characterization of Yeast Strains with Ketoreductase Activity for Bioreduction of Ketones

Pál Csuka,Csaba Paizs,László Poppe,László Nagy-Győr,Zsófia Molnár,Viktória Bódai

doi:10.3311/ppch.17429

Abstract

This study describes six yeast strains for stereoselective ketone reductions. The reaction conditions for the yeast strains (Pichia carsonii, Lodderomyces elongisporus, Candida norvegica, Candida guillermondi, Debaromyces fabryi and Candida parapsilosis) were optimized in a design of experiments for three ketones of different properties. The pH tolerance, temperature stability and productivity of the bioreductions with lyophilized cells of the yeast strains were characterized. In several cases, the optimized bioreductions resulted in enantiopure alcohols (ee > 99 %) with conversions ranging from moderate to excellent.

Highlights

Whole-cell biocatalysts are applicable biomaterials which can be used in various fields such as food industry, agriculture, and fine chemical industry including the pharmaceutical industry
3 Results and discussion The six yeast strains investigated in this study [(Pichia carsonii (WY1), Lodderomyces elongisporus (WY2), Candida norvegica (WY4), Candida guillermondi (WY7), Debaromyces fabryi (WY11) and Candida parapsilosis (WY12)] were chosen from the Witaria strain collection to demonstrate the usability and adaptability of the yeasts as whole-cell biocatalysts in ketoreductions
4 Conclusion This study indicated that lyophilized yeast cells having excellent long-term storage stability are easy-to-handle biocatalysts for ketoreductions resulting in cost-effective synthesis like with recombinant enzymes

Summary

Introduction

Whole-cell biocatalysts are applicable biomaterials which can be used in various fields such as food industry, agriculture, and fine chemical industry including the pharmaceutical industry. Whole-cell biocatalysts have several advantages over isolated enzymes [1]. Since whole cells have several sets of metabolic enzymes, they can be utilized in various types of reactions with different substrates. It is possible to use the same whole-cell biocatalyst to produce different products, and by-products can be back-converted into main product with properly chosen reaction conditions. The growing need of chiral Active Pharmaceutical Ingredients (APIs) creates a demand for novel and promising biocatalysts, such as yeasts [3,4,5]. The ketoreductase enzyme family is extensively researched and utilized as biocatalysts to create enantiopure alcohols from the corresponding prochiral ketones [5]

Methods

Results

Conclusion