Biocatalysis has found numerous applications in various fields as an alternative to chemical catalysis. The use of enzymes in organic synthesis, especially to make chiral compounds for pharmaceuticals as well for the flavors and fragrance industry, are the most prominent examples. In addition, biocatalysts are used on a large scale to make specialty and even bulk chemicals. This review intends to give illustrative examples in this field with a special focus on scalable chemical production using enzymes. It also discusses the opportunities and limitations of enzymatic syntheses using distinct examples and provides an outlook on emerging enzyme classes.

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Biocatalysis: Enzymatic Synthesis for Industrial Applications

Analytical strategies for LC–MS-based targeted metabolomics ☆

Multi-enzymatic cascade reactions, i.e., the combination of several enzymatic transformations in concurrent one-pot processes, offer considerable advantages: the demand of time, costs and chemicals for product recovery may be reduced, reversible reactions can be driven to completion and the concentration of harmful or unstable compounds can be kept to a minimum. This review summarizes the developments in multi-enzymatic cascades employed for the asymmetric synthesis of chiral alcohols, amines and amino acids, as well as for CC bond formation. In addition, a general classification of biocatalytic cascade systems is provided and bioprocess engineering aspects associated with the topic are discussed.

Multi-Enzymatic Cascade Reactions: Overview and Perspectives

Practical chiral alcohol manufacture using ketoreductases.

Enzymes are able to perform reactions under mild conditions, e.g., pH and temperature, with remarkable chemo-, regio-, and stereoselectivity. Because of 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. These reactions can be catalyzed by either isolated enzymes or whole cells that exhibit ketone-reducing activity. The use of isolated enzymes is often preferred because of a higher volumetric productivity and the absence of side reactions. Both types of catalysts have also deficiencies limiting their use in synthesis of chiral alcohols. 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. In this paper, strategies for cofactor regeneration in biocatalytic ketone reduction are reviewed. Furthermore, different processes carried out on laboratory and industrial scales using isolated enzymes are presented. Attention is turned to process parameters, e.g., conversion, yield, enantiomeric excess, and process strategies, e.g., the application of biphasic systems or methods of in situ (co)product recovery. The biocatalytic production of chiral alcohols utilizing whole cells is presented in part II of this review.

Biocatalytic ketone reduction--a powerful tool for the production of chiral alcohols--part I: processes with isolated enzymes

In recent years, metabolomics developed to an accepted and valuable tool in life sciences Substantial improvements of analytical hardware allow metabolomics to run routinely now Data are successfully used to investigate genotype–phenotype relations of strains and mutants Metabolomics facilitates metabolic engineering to optimise mircoorganisms for white biotechnology and spreads to the investigation of biotransformations and cell culture Metabolomics serves not only as a source of qualitative but also quantitative data of intra-cellular metabolites essential for the model-based description of the metabolic network operating under in vivo conditions To collect reliable metabolome data sets, culture and sampling conditions, as well as the cells’ metabolic state, are crucial Hence, application of biochemical engineering principles and method standardisation efforts become important Together with the other more established omics technologies, metabolomics will strengthen its claim to contribute to the detailed understanding of the in vivo function of gene products, biochemical and regulatory networks and, even more ambitious, the mathematical description and simulation of the whole cell in the systems biology approach This knowledge will allow the construction of designer organisms for process application using biotransformation and fermentative approaches making effective use of single enzymes, whole microbial and even higher cells

Metabolomics: current state and evolving methodologies and tools.

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.

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

Cytochrome P450 monooxygenases (CYPs) are important enzymes in the metabolism of xenobiotics. Therefore, several approaches to clone and overexpress the human isoforms have been made. In addition to microsomes or S9 preparations, these recombinant human isoforms have found diverse application in drug development. We discuss and give examples of the use of bacterial whole cell systems with rec. human CYPs for the preparative scale synthesis of drug metabolites.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/bit.22775

Kirsten Schroer

Papers

Biocatalytic ketone reduction--a powerful tool for the production of chiral alcohols--part I: processes with isolated enzymes

Metabolomics: current state and evolving methodologies and tools.

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

Recombinant human cytochrome P450 monooxygenases for drug metabolite synthesis

High cell density cultivation of recombinant yeasts and bacteria under non-pressurized and pressurized conditions in stirred tank bioreactors.