A Multi-Enzyme Cascade for the Production of High-Value Aromatic Compounds

Claudia Engelmann,Andreas Liese,Georg Fieg,Thomas Waluga,Jens Johannsen,Paul Bubenheim

doi:10.3390/catal10101216

Claudia Engelmann, Andreas Liese + Show 4 more

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https://doi.org/10.3390/catal10101216

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Abstract

Cascade reactions are the basis of life in nature and are adapted to research and industry in an increasing manner. The focus of this study is the production of the high-value aromatic ester cinnamyl cinnamate, which can be applied in flavors and fragrances. A three-enzyme cascade was established to realize the synthesis, starting from the corresponding aldehyde with in situ cofactor regeneration in a two-phase system. After characterization of the enzymes, a screening with different organic solvents was carried out, whereby xylene was found to be the most suitable solvent for the second phase. The reaction stability of the formate dehydrogenase (FDH) from Candida boidinii is the limiting step during cofactor regeneration. However, the applied enzyme cascade showed an overall yield of 54%. After successful application on lab scale, the limitation by the FDH was overcome by immobilization of the enzymes and an optimized downstream process, transferring the cascade into a miniplant. The upscaling resulted in an increased yield for the esterification, as well as overall yields of 37%.

Highlights

Based on a long history, e.g., beer brewing or cheese fermentation, biocatalysis is a highly important method in industry
Since the storage stability of the enzyme is comparably high al. detected only up to 2.5% residual activity with those emulsions based on application of [47], these results indicate that the formate dehydrogenase (FDH) is deactivated by the reaction itself
The enzymes in the aqueous phase forin thethe cinnamyl aldehyde reduction,in the FDHin from boidinii, showed kinetics to those described in literature

Summary

Introduction

Based on a long history, e.g., beer brewing or cheese fermentation, biocatalysis is a highly important method in industry. Thereby, biocatalytic cascades play a fundamental role in nature and in biotechnology where they show great advantages, such as environmental friendliness, less intermediate separation, and more sustainable reactions due to less byproduct formation. Different methods are used to improve the productivity of biotechnological processes, whereby the cores of research are an efficient cofactor regeneration and the downstream processing [1,2]. The enzyme group of oxidoreductases require cofactors, which are often very cost intensive, constituting the need for their regeneration. This is often realized by using a second enzymatic reaction, since enzymes are highly selective and efficient. Important applications for cofactor regeneration are, e.g., the synthesis of chiral alcohols by the reduction in prochiral ketons via ketoreductases with an integrated cofactor regeneration by a glucose dehydrogenase [3]

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