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237 results on '"Winkler, Margit"'

11. Enzymes revolutionize the bioproduction of value-added compounds: From enzyme discovery to special applications

Author

Wiltschi, Birgit, Cernava, Tomislav, Dennig, Alexander, Galindo Casas, Meritxell, Geier, Martina, Gruber, Steffen, Haberbauer, Marianne, Heidinger, Petra, Herrero Acero, Enrique, Kratzer, Regina, Luley-Goedl, Christiane, Müller, Christina A., Pitzer, Julia, Ribitsch, Doris, Sauer, Michael, Schmölzer, Katharina, Schnitzhofer, Wolfgang, Sensen, Christoph W., Soh, Jung, Steiner, Kerstin, Winkler, Christoph K., Winkler, Margit, and Wriessnegger, Tamara

Published
2020
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16. Nature stays natural: two novel chemo-enzymatic one-pot cascades for the synthesis of fragrance and flavor aldehydes.

Author

Giparakis, Stefan, Winkler, Margit, and Rudroff, Florian

Subjects
*BAEYER-Villiger rearrangement, *ALCOHOL oxidation, *ALDEHYDES, *ALCOHOL dehydrogenase, *DOUBLE bonds, *PSEUDOMONAS putida, *FLAVOR, *FLAVORING essences
Abstract

Novel synthetic strategies for the production of high-value chemicals based on the 12 principles of green chemistry are highly desired. Herein, we present a proof of concept for two novel chemo-enzymatic one-pot cascades allowing for the production of valuable fragrance and flavor aldehydes. We utilized renewable phenylpropenes, such as eugenol from cloves or estragole from estragon, as starting materials. For the first strategy, Pd-catalyzed isomerization of the allylic double bond and subsequent enzyme-mediated (aromatic dioxygenase, ADO) alkene cleavage were performed to obtain the desired aldehydes. In the second route, the double bond was oxidized to the corresponding ketone via a copper-free Wacker oxidation protocol followed by enzymatic Baeyer–Villiger oxidation (phenylacetone monooxygenase from Thermobifida fusca), esterase-mediated (esterase from Pseudomonas fluorescens, PfeI) hydrolysis and subsequent oxidation of the primary alcohol (alcohol dehydrogenase from Pseudomonas putida, AlkJ) to the respective aldehyde products. Eight different phenylpropene derivatives were subjected to these reaction sequences, allowing for the synthesis of seven aldehydes in up to 55% yield after 4 reaction steps (86% for each step). [ABSTRACT FROM AUTHOR]

Published
2024
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17. CO2-based production of phytase from highly stable expression plasmids in Cupriavidus necator H16.

Author

Arhar, Simon, Rauter, Thomas, Stolterfoht-Stock, Holly, Lambauer, Vera, Kratzer, Regina, Winkler, Margit, Karava, Marianna, Kourist, Robert, and Emmerstorfer-Augustin, Anita

Subjects
GENE expression, PHYTASES, SYNTHETIC biology, PLASMIDS, CALVIN cycle, BIOMASS
Abstract

Background: Existing plasmid systems offer a fundamental foundation for gene expression in Cupriavidus necator; however, their applicability is constrained by the limitations of conjugation. Low segregational stabilities and plasmid copy numbers, particularly in the absence of selection pressure, pose challenges. Phytases, recognized for their widespread application as supplements in animal feed to enhance phosphate availability, present an intriguing prospect for heterologous production in C. necator. The establishment of stable, high-copy number plasmid that can be electroporated would support the utilization of C. necator for the production of single-cell protein from CO2. Results: In this study, we introduce a novel class of expression plasmids specifically designed for electroporation. These plasmids contain partitioning systems to boost segregation stability, eliminating the need for selection pressure. As a proof of concept, we successfully produced Escherichia coli derived AppA phytase in C. necator H16 PHB− 4 using these improved plasmids. Expression was directed by seven distinct promoters, encompassing the constitutive j5 promoter, hydrogenase promoters, and those governing the Calvin-Benson-Bassham cycle. The phytase activities observed in recombinant C. necator H16 strains ranged from 2 to 50 U/mg of total protein, contingent upon the choice of promoter and the mode of cell cultivation - heterotrophic or autotrophic. Further, an upscaling experiment conducted in a 1 l fed-batch gas fermentation system resulted in the attainment of the theoretical biomass. Phytase activity reached levels of up to 22 U/ml. Conclusion: The new expression system presented in this study offers a highly efficient platform for protein production and a wide array of synthetic biology applications. It incorporates robust promoters that exhibit either constitutive activity or can be selectively activated when cells transition from heterotrophic to autotrophic growth. This versatility makes it a powerful tool for tailored gene expression. Moreover, the potential to generate active phytases within C. necator H16 holds promising implications for the valorization of CO2 in the feed industry. [ABSTRACT FROM AUTHOR]

Published
2024
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27. Structure of the Reductase Domain of a Fungal Carboxylic Acid Reductase and Its Substrate Scope in Thioester and Aldehyde Reduction

Author

Daniel, Bastian, primary, Hashem, Chiam, additional, Leithold, Marlene, additional, Sagmeister, Theo, additional, Tripp, Adrian, additional, Stolterfoht-Stock, Holly, additional, Messenlehner, Julia, additional, Keegan, Ronan, additional, Winkler, Christoph K., additional, Ling, Jonathan Guyang, additional, Younes, Sabry H.H., additional, Oberdorfer, Gustav, additional, Abu Bakar, Farah Diba, additional, Gruber, Karl, additional, Pavkov-Keller, Tea, additional, and Winkler, Margit, additional

Published
2022
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28. Scanning aldoxime dehydratase sequence space and characterization of a new aldoxime dehydratase from Fusarium vanettenii

Author

Křístková, Barbora, primary, Rädisch, Robert, additional, Kulik, Natalia, additional, Horvat, Melissa, additional, Rucká, Lenka, additional, Grulich, Michal, additional, Rudroff, Florian, additional, Kádek, Alan, additional, Pátek, Miroslav, additional, Winkler, Margit, additional, and Martínková, Ludmila, additional

Published
2022
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33. Adipose triglyceride lipase–mediated lipid catabolism is essential for bronchiolar regeneration

Author

Kanti, Manu Manjunath, primary, Striessnig-Bina, Isabelle, additional, Wieser, Beatrix Irene, additional, Schauer, Silvia, additional, Leitinger, Gerd, additional, Eichmann, Thomas O., additional, Schweiger, Martina, additional, Winkler, Margit, additional, Winter, Elke, additional, Lana, Andrea, additional, Kufferath, Iris, additional, Marsh, Leigh Matthew, additional, Kwapiszewska, Grazyna, additional, Zechner, Rudolf, additional, Hoefler, Gerald, additional, and Vesely, Paul Willibald, additional

Published
2022
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34. Organic Acid to Nitrile: A Chemoenzymatic Three‐Step Route.

Author

Winkler, Margit, Horvat, Melissa, Schiefer, Astrid, Weilch, Victoria, Rudroff, Florian, Pátek, Miroslav, and Martínková, Ludmila

Subjects
*ALCOHOL dehydrogenase, *CARBOXYLIC acids, *ORGANIC acids, *HEAVY metals, *CD19 antigen, *CYANIDES, *ENZYMES
Abstract

Various widely applied compounds contain cyano‐groups, and this functional group serves as a chemical handle for a whole range of different reactions. We report a cyanide free chemoenzymatic cascade for nitrile synthesis. The reaction pathway starts with a reduction of carboxylic acid to aldehyde by carboxylate reductase enzymes (CARs) applied as living cell biocatalysts. The second – chemical – step includes in situ oxime formation with hydroxylamine. The final direct step from oxime to nitrile is catalyzed by aldoxime dehydratases (Oxds). With compatible combinations of a CAR and an Oxd, applied in one‐pot two‐step reactions, several aliphatic and aryl‐aliphatic target nitriles were obtained in more than 80% conversion. Phenylacetonitrile, for example, was prepared in 78% isolated yield. This chemoenzymatic route does not require cyanide salts, toxic metals, or undesired oxidants in contrast to entirely chemical procedures. [ABSTRACT FROM AUTHOR]

Published
2023
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36. Chemoenzymatic one-pot reaction from carboxylic acid to nitrile via oxime

Author

Horvat, Melissa, primary, Weilch, Victoria, additional, Rädisch, Robert, additional, Hecko, Sebastian, additional, Schiefer, Astrid, additional, Rudroff, Florian, additional, Wilding, Birgit, additional, Klempier, Norbert, additional, Pátek, Miroslav, additional, Martínková, Ludmila, additional, and Winkler, Margit, additional

Published
2022
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37. Oxidations

Author

Hanlon, Steven P., primary, Kittelmann, Matthias, additional, and Winkler, Margit, additional

Published
2016
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39. Chemo-Enzymatic Cascade for the Generation of Fragrance Aldehydes

Author

Schwendenwein, Daniel, Ressmann, Anna K., Entner, Marcello, Savic, Viktor, Winkler, Margit, and Rudroff, Florian

Subjects
Chemistry, Chemical technology, carboxylic acid reductase, Heck-coupling, TP1-1185, ene reductase, QD1-999, chemo-enzymatic cascade, fragrance aldehydes
Abstract

In this study, we present the synthesis of chiral fragrance aldehydes, which was tackled by a combination of chemo-catalysis and a multi-enzymatic in vivo cascade reaction and the development of a highly versatile high-throughput assay for the enzymatic reduction of carboxylic acids. We investigated a biocompatible metal-catalyzed synthesis for the preparation of α or β substituted cinnamic acid derivatives which were fed directly into the biocatalytic system. Subsequently, the target molecules were synthesized by an enzymatic cascade consisting of a carboxylate reduction, followed by the selective C-C double bond reduction catalyzed by appropriate enoate reductases. We investigated a biocompatible oxidative Heck protocol and combined it with cells expressing a carboxylic acid reductase from Neurospora crassa (NcCAR) and an ene reductase from Saccharomyces pastorianus for the production fragrance aldehydes.

Published
2021

42. The sustainable synthesis of levetiracetam by an enzymatic dynamic kinetic resolution and an ex-cell anodic oxidation

Author

Arndt, Sebastian, primary, Grill, Birgit, additional, Schwab, Helmut, additional, Steinkellner, Georg, additional, Pogorevčnik, Urška, additional, Weis, Dominik, additional, Nauth, Alexander M., additional, Gruber, Karl, additional, Opatz, Till, additional, Donsbach, Kai, additional, Waldvogel, Siegfried R., additional, and Winkler, Margit, additional

Published
2021
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50. Selective Enzymatic Transformation to Aldehydes in vivo by Fungal Carboxylate Reductase from Neurospora crassa

Author

Schwendenwein, Daniel, Fiume, Giuseppe, Weber, Hansjörg, Rudroff, Florian, and Winkler, Margit

Subjects
carboxylic acids, Full Paper, biocatalysis, aldehydes, flavours and fragrances, Full Papers, carboxylate reductase
Abstract

The enzymatic reduction of carboxylic acids is in its infancy with only a handful of biocatalysts available to this end. We have increased the spectrum of carboxylate‐reducing enzymes (CARs) with the sequence of a fungal CAR from Neurospora crassa OR74A (NcCAR). NcCAR was efficiently expressed in E. coli using an autoinduction protocol at low temperature. It was purified and characterized in vitro, revealing a broad substrate acceptance, a pH optimum at pH 5.5–6.0, a T m of 45 °C and inhibition by the co‐product pyrophosphate which can be alleviated by the addition of pyrophosphatase. The synthetic utility of NcCAR was demonstrated in a whole‐cell biotransformation using the Escherichia coli K‐12 MG1655 RARE strain in order to suppress overreduction to undesired alcohol. The fragrance compound piperonal was prepared from piperonylic acid (30 mM) on gram scale in 92 % isolated yield in >98% purity. This corresponds to a productivity of 1.5 g/L/h.

Published
2016

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