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Item type:Publication, Access status: with files , Bioreactive separation technology: a retrospective and perspective(Elsevier, 2026-03-28); ; ; ; Bluemke, WilfriedBiocatalysis, using enzymes or whole cells, offers high selectivity under mild conditions, but its broader application is often hindered by slow kinetics, equilibrium limitations, product inhibition and the processing of dilute streams in the presence of enzymes and cells. Bioreactive separation, defined as the simultaneous process of biocatalysis and separation, provides a powerful concept to overcome these barriers and therefore offers the potential of superiority over conventional processes. The current retro- and perspective paper, which is the result of an interdisciplinary workshop with academic and industry experts from the areas of biotechnology, fluid separations and process systems engineering, provides a focussed review, paired with a distinct novel definition of bioreactive separations that links to multifunctional reactors in chemical engineering and in situ product removal in biocatalysis. By establishing a common framework, this definition connects different research areas and enables systematic development. The current status of bioreactive separation processes is evaluated using SWOT analyses to identify key potentials and challenges. Based on this, a vision for 2040 is outlined, highlighting the need for advances in integration strategies, biocatalyst design, modelling and simulation, and applied research. Overall, a coordinated progress in these areas can significantly enhance the scalability and sustainability of bioprocessing.Publicationtype: Review Article48 31 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Enzyme and reaction engineering of unspecific peroxygenase driven hydroxylation of butane (BUPOx)(2025-03-31); In this study, scalable biocatalytic processes were developed in which unspecific peroxygenase (UPO) is used for selective oxyfunctionalization. The most important challenges in terms of enzyme production and stability, controlled electrochemical generation of cosubstrates, in situ product removal and semi-continuous operability were addressed. Robust UPO expression and downstream strategies enabled continuous operation, while detailed kinetic characterisation showed that a precise balance between substrate and hydrogen peroxide concentrations is required to prevent oxidative inactivation. Immobilised UPO such as His-tag, Twin-Strep-labelled and YSD (yeast surface display) variants, achieved high activity retention and operational stability in fluidised bed systems, enabling longer reaction cycles and simplified product recovery.Publicationtype: Report10 10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Extracellular Bacterial Production of DNA Hydrogels–Toward Engineered Living Materials(Wiley, 2025); ; ; 5 8 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Yeast surface display enables one-step production and immobilization of unspecific peroxygenasesUnspecific peroxygenases (UPOs) are regarded as a “dream catalyst” for selective oxyfunctionalization reactions like oxygenations. We present the display of the model UPO rAaeUPO (PaDa−I) on the cell surface of the heterologous production host Komagataella phaffii as a one-step production and immobilization process. The coding sequence for PaDa−I was combined with genes coding for cell wall proteins from Saccharomyces cerevisiae and transformed into K. phaffii. The fusion proteins were compared among each other and with secreted, free PaDa−I. One system in particular, a C-terminal fusion of PaDa−I and Sag1 yielded near identical activity per volume culture broth to the secreted PaDa−I with ~90 % of the activity being at the cell wall. The surface display simplifies downstream processing and includes immobilization on a cheap, retainable and replaceable matrix, that is the production host itself. The enzymes remained active in a repeated batch process for 10 batches and 200 h of catalysis.Publicationtype: Journal Article14 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Electrochemical H₂O₂ - stat mode as reaction concept to improve the process performance of an unspecific peroxygenase(Elsevier, 2023-12-25); ; ; ; The electroenzymatic hydroxylation of 4-ethylbenzoic acid catalyzed by the recombinant unspecific peroxygenase from the fungus Agrocybe aegerita (rAaeUPO) was performed in a gas diffusion electrode (GDE)-based system. Enzyme stability and productivity are significantly affected by the way the co-substrate hydrogen peroxide (H2O2) is supplied. In this study, two in-situ electrogeneration modes of H2O2 were established and compared. Experiments under galvanostatic conditions (constant productivity of H2O2) were conducted at current densities spanning from 0.8 mA cm−2 to 6.4 mA cm−2. For comparison, experiments under H2O2-stat mode (constant H2O2 concentration) were performed. Here, four H2O2 concentrations between 0.06 mM and 0.28 mM were tested. A maximum H2O2 productivity of 5.5 µM min−1 cm−2 and productivity of 10.5 g L−1 d−1 were achieved under the galvanostatic condition at 6.4 mA cm−2. Meanwhile, the highest total turnover number (TTN) of 710,000 mol mol−1 and turnover frequency (TOF) of 87.5 s−1 were obtained under the H2O2-stat mode at concentration limits of 0.15 mM and 0.28 mM, respectively. The most favorable outcome in terms of maximum achievable TTN, TOF and productivity was found under the H2O2-stat mode at concentration limit of 0.2 mM. Here, a TTN of 655,000 mol mol−1, a TOF of 80.3 s−1 and a productivity of 6.1 g L−1 d−1 were achieved. The electrochemical H2O2-stat mode not only offers a promising alternative reaction concept to the well-established galvanostatic mode but also enhances the process performance of unspecific peroxygenases.Publicationtype: Journal ArticleScopus© Citations 1 67 160 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Quantitative and non-quantitative assessments of enzymatic electrosynthesis: A case study of parameter requirements(Wiley, 2023-12-13); ; The integration of enzymatic and electrochemical reactions offers a unique opportunity to optimize production processes. Recently, an increasing number of laboratory-scale enzymatic electrosyntheses have shown impressive performance indicators, leading to scientific interest in technical implementation. However, important process parameters are missing in most of the relevant literature. On one hand, this is due to the large variety of relevant performance indicators. On the other hand, enzyme technologists and electrochemists use different parameters to describe a process. In this article, we review the most important performance indicators in electroenzymatic processes and suggest that in order to allow quantitative comparison, these indicators should be reported in all respective publications. In addition to quantitative parameters, non-quantitative assessments often need to be included in a final evaluation. Examples of such parameters are sustainability, contribution to the UN Sustainable Development Goals or interactions with the overall process. We demonstrate the evaluation of processes using hydrogen peroxide-dependent peroxygenases. The strength of the proposed evaluation system lies in its ability to identify weaknesses in a process at an early stage of development. Finally, it can be concluded that all evaluated enzymatic electrosynthesis do not yet meet typical industrial requirements for an enzyme-based process.Publicationtype: Journal ArticleScopus© Citations 1 36 50 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Application of the all-in-one electrode for in situ H2O2 generation in hydroxylation catalyzed by unspecific peroxygenase from Agrocybe aegerita(2023-08-01); ; ; ; The versatile unspecific peroxygenase from the fungus Agrocybe aegerita (AaeUPO) is capable to perform hydroxylation of various substrates, even unactivated C[sbnd]H bonds. The technical application of AaeUPO is still limited due to an instability towards its co-substrate hydrogen peroxide (H2O2). Electrochemical synthesis of H2O2 is an attractive approach that provides controllable in situ generation of H2O2. The aims of this study are to promote catalyst efficiency and develop an individually tailored system for H2O2-dependent reactions. Herein, an All-in-One electrode (AiO) system with a carbon felt cathode is used to generate H2O2 in situ and combined for the first time with an enzymatic hydroxylation. The AiO electrode combines the counter and working electrode in a single rod structure. This shape provides convenient integration into conventional bioreactors, thus, converting them into bioelectrochemical systems (BES). Hydroxylation of 4-ethylbenzoic acid (EBA) catalyzed by the recombinant AaeUPO (rAaeUPO) was chosen as the model reaction. Total turnover number (TTN) up to 450,000 mol mol−1 and turnover frequency (TOF) up to 7.7 s −1 were achieved using the AiO electrode system. The H2O2 productivity was identified as the limiting factor in the hydroxylation of EBA. However, with numbering-up or surface enlargement, this process could have great potential as an optimizable platform for H2O2-dependent enzymatic reactions.Publicationtype: Journal Article109 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Process intensification as game changer in enzyme catalysis(Frontiers Media S.A., 2022-03-21); ; ; ; 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. Different topics (like limited specific activity, unfavourable kinetics or limited enzyme stability) can be addressed via enzyme engineering. On the other hand, there is also a long list of topics that are not addressable by enzyme engineering. Here typical examples are unfavourable reaction thermodynamics, selectivity in multistep reactions or low water solubility. These challenges can only be addressed through an adaption of the reaction system. The procedures of process intensification (PI) represent a good approach to reach most suitable systems. The general objective of PI is to achieve significant benefits in terms of capital and operating costs as well as product quality, waste, and process safety by applying innovative principles. The aim of the review is to show the current capabilities and future potentials of PI in enzyme catalysis focused on enzymes of the class of oxidoreductases. The focus of the paper is on alternative methods of energy input, innovative reactor concepts and reaction media with improved properties.Publicationtype: Journal Article215 363 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Enzymatic Oxidation of Butane to 2-Butanol in a Bubble Column(Wiley, 2020-06-09); ; ; ; 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 demonstrate the application of a peroxygenase for the hydroxylation of the inert, gaseous substrate butane to 2-butanol in a bubble column reactor. The influence of hydrogen peroxide feed rate and enzyme loading on product formation, overoxidation to butanone and catalytic efficiency is investigated at 200 mL scale. The process is scaled up to 2 L and coupled with continuous extraction. This setup allowed the production of 115 mmol 2-butanol and 70 mmol butanone with an overall total turnover number (TTN) of over 15.000, thereby demonstrating the applicability of peroxygenases for preparative hydroxylation of such inert, gaseous substrates at mild reaction conditions.Publicationtype: Journal ArticleScopus© Citations 11 494 302 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Biocatalytic oxyfunctionalization of butane in a bubble‐column reactorPublicationtype: Journal Article64