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Holtmann, Dirk (author), Hollmann, F. (author), Bouchaut, B.F.H.J. (author)In September 2015, the United Nations General Assembly established the 2030 Agenda for Sustainable Development, which includes 17 Sustainable Development Goals (SDGs) [...].journal article 2023
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Wang, Y. (author), Teetz, Niklas (author), Holtmann, Dirk (author), Alcalde, Miguel (author), van Hengst, J.M.A. (author), Liu, Xiaoxiao (author), Wang, Mengfan (author), Qi, Wei (author), Zhang, Wuyuan (author), Hollmann, F. (author)Biocatalytic oxidation reactions of toluene derivates to the corresponding aldehydes are typically challenged by regio- and chemoselectivity issues. In this contribution we address both challenges by a combined reactant- and reaction engineering approach. We demonstrate that the peroxygenase-catalysed transformation of ring-substituted...journal article 2023
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Langsdorf, Alexander (author), Volkmar, Marianne (author), Ulber, Roland (author), Hollmann, F. (author), Holtmann, Dirk (author)Green waste, especially of municipal origin, is currently used as a material only to a limited extent. However, the large material flows could also be used in a more economical way if they were integrated into biorefinery concepts. Besides the production of basic and fine chemicals, green waste could also be used as source of industrial...journal article 2023
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Burek, Bastien O. (author), Dawood, A.W.H. (author), Hollmann, F. (author), Liese, Andreas (author), Holtmann, Dirk (author)Enzyme catalysis, made tremendous progress over the last years in identification of new enzymes and new enzymatic reactivity’s as well as optimization of existing enzymes. However, the performance of the resulting processes is often still limited, e.g., in regard of productivity, realized product concentrations and the stability of the enzymes....journal article 2022
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- Holtmann, Dirk (author), Hollmann, F. (author) journal article 2022
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Hobisch, Markus (author), Holtmann, Dirk (author), Gomez de Santos, Patricia (author), Alcalde, Miguel (author), Hollmann, F. (author), Kara, Selin (author)Peroxygenases are an emerging new class of enzymes allowing selective oxyfunctionalisation reactions in a cofactor-independent way different from well-known P450 monooxygenases. Herein, we focused on recent developments from organic synthesis, molecular biotechnology and reaction engineering viewpoints that are devoted to bring these enzymes...review 2021
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Hollmann, F. (author), Ulber, Roland (author), Holtmann, Dirk (author)In chemical process engineering, process intensification (PI) has proven itself as a method that resulted very often in processes with an at least doubled process performance. In recent years, the PI techniques have found more and more applications in biotechnology. Exemplary continuous processes, single-use reactors, electrobiotechnology and...review 2021
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Holtmann, Dirk (author), Hollmann, F. (author)Process intensification aims at enabling bridging the gap between fundamental research such as identification of new catalysts and reactions and their implementation in industrial environments. Especially the field of biocatalysis has seen some tremendous improvements and the development of new tools and approaches to bridge this gap. In this...journal article 2021
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Perz, Frederic (author), Bormann, Sebastian (author), Ulber, Roland (author), Alcalde, Miguel (author), Bubenheim, Paul (author), Hollmann, F. (author), Holtmann, Dirk (author), Liese, Andreas (author)Unspecific peroxygenases have recently gained significant interest due to their ability to catalyse the hydroxylation of non-activated C−H bonds using only hydrogen peroxide as a co-substrate. However, the development of preparative processes has so far mostly concentrated on benzylic hydroxylations using liquid substrates. Herein, we...journal article 2020
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Bormann, Sebastian (author), van Schie, M.M.C.H. (author), Pedroso de Almeida, T. (author), Zhang, W. (author), Stöckl, Markus (author), Ulber, Roland (author), Hollmann, F. (author), Holtmann, Dirk (author)Various enzymes utilize hydrogen peroxide as an oxidant. Such “peroxizymes” are potentially very attractive catalysts for a broad range of oxidation reactions. Most peroxizymes, however, are inactivated by an excess of H<sub>2</sub>O<sub>2</sub>. The electrochemical reduction of oxygen can be used as an in situ generation method for hydrogen...journal article 2019
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Burek, B. O. (author), Bormann, S. (author), Hollmann, F. (author), Bloh, J. Z. (author), Holtmann, D. (author)In general, hydrogen peroxide is a stable and relatively mild oxidant and it can be regarded as the ultimate "green" reagent because water and oxygen are the only by-products. Besides the direct application of H<sub>2</sub>O<sub>2</sub> in chemical processes more and more enzymatic syntheses based on hydrogen peroxide were developed....review 2019
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Burek, Bastien O. (author), de Boer, Sabrina R. (author), Tieves, F. (author), Zhang, W. (author), van Schie, M.M.C.H. (author), Bormann, Sebastian (author), Alcalde, Miguel (author), Holtmann, Dirk (author), Hollmann, F. (author)Photoenzymatic cascades can be used for selective oxygenation of C−H-Bonds under mild conditions circumventing the hydrogen peroxide mediated peroxygenase inactivation via in situ H<sub>2</sub>O<sub>2</sub> generation. Here, we report the “on demand” production of hydrogen peroxide via methanol assisted reduction of molecular oxygen using UV...journal article 2019
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Tosstorff, Andreas (author), Kroner, Cora (author), Opperman, Diederik J. (author), Hollmann, F. (author), Holtmann, Dirk (author)Old yellow enzymes are able to catalyze asymmetric C=C reductions. A mediated electroenzymatic process to regenerate the NADPH in combination with an old yellow enzyme was investigated. Due to the fact that the overall process was affected by a broad set of parameters, a design of experiments (DoE) approach was chosen to identify suitable...journal article 2017
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Holtmann, Dirk (author), Hollmann, F. (author)Monooxygenases are promising catalysts because they in principle enable the organic chemist to perform highly selective oxyfunctionalisation reactions that are otherwise difficult to achieve. For this, monooxygenases require reducing equivalents, to allow reductive activation of molecular oxygen at the enzymes' active sites. However, these...journal article 2016
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Fernandez Fueyo, E. (author), Younes, S.H.H. (author), Van Rootselaar, Stefan (author), Aben, René W M (author), Renirie, R. (author), Wever, Ron (author), Holtmann, Dirk (author), Rutjes, Floris P J T (author), Hollmann, F. (author)A catalytic, enzyme-initiated (aza-) Achmatowicz reaction is presented. The involvement of a robust vanadium-dependent peroxidase from Curvularia inaequalis allows the simple use of H<sub>2</sub>O<sub>2</sub> and catalytic amounts of bromide.journal article 2016
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Bormann, S. (author), Gomez Baraibar, A. (author), Ni, Y. (author), Holtmann, D. (author), Hollmann, F. (author)Peroxygenases enable H2O2-driven oxyfunctionalisation of organic compounds such as selective epoxidation, hydroxylation and heteroatom oxygenation. Therefore, peroxygenases are potentially very useful tools for the organic chemist. This contribution reviews the current state of the art in peroxygenases, their availability, engineering and...journal article 2015
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Holtmann, D. (author), Fraaije, M.W. (author), Arends, I.W.C.E. (author), Oppermand, D.J. (author), Hollmann, F. (author)The scope and limitations of oxygenases as catalysts for preparative organic synthesis is discussed.journal article 2014
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Kochius, S. (author), Magnusson, A.O. (author), Hollmann, F. (author), Schrader, J. (author), Holtmann, D. (author)The applicability of dissolved redox mediators for NAD(P)+ regeneration has been demonstrated several times. Nevertheless, the use of mediators in solutions for sensor applications is not a very convenient strategy since the analysis is not reagentless and long stabilization times occur. The most important drawbacks of dissolved mediators in...journal article 2012