TY - CHAP A1 - Kreyer, Jörg A1 - Stollenwerk, Dominik A1 - Schöning, Michael Josef T1 - Tagung des Forschernachwuchses der FH Aachen 20. November 2013 / ed.: J. Kreyer, D. Stollenwerk, M. J. Schöning Y1 - 2013 PB - FH Aachen CY - Aachen ER - TY - JOUR A1 - Muschallik, Lukas A1 - Kipp, Carina Ronja A1 - Recker, Inga A1 - Bongaerts, Johannes A1 - Pohl, Martina A1 - Gelissen, Melanie A1 - Schöning, Michael Josef A1 - Selmer, Thorsten A1 - Siegert, Petra T1 - Synthesis of α-hydroxy ketones and vicinal diols with the Bacillus licheniformis DSM 13T butane-2, 3-diol dehydrogenase JF - Journal of Biotechnology N2 - The enantioselective synthesis of α-hydroxy ketones and vicinal diols is an intriguing field because of the broad applicability of these molecules. Although, butandiol dehydrogenases are known to play a key role in the production of 2,3-butandiol, their potential as biocatalysts is still not well studied. Here, we investigate the biocatalytic properties of the meso-butanediol dehydrogenase from Bacillus licheniformis DSM 13T (BlBDH). The encoding gene was cloned with an N-terminal StrepII-tag and recombinantly overexpressed in E. coli. BlBDH is highly active towards several non-physiological diketones and α-hydroxyketones with varying aliphatic chain lengths or even containing phenyl moieties. By adjusting the reaction parameters in biotransformations the formation of either the α-hydroxyketone intermediate or the diol can be controlled. Y1 - 2020 SN - 2590-1559 U6 - http://dx.doi.org/10.1016/j.jbiotec.2020.09.016 VL - 202 IS - Vol. 324 SP - 61 EP - 70 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Muschallik, Lukas A1 - Molinnus, Denise A1 - Jablonski, Melanie A1 - Kipp, Carina Ronja A1 - Bongaerts, Johannes A1 - Pohl, Martina A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Selmer, Thorsten A1 - Siegert, Petra T1 - Synthesis of α-hydroxy ketones and vicinal (R, R)-diols by Bacillus clausii DSM 8716ᵀ butanediol dehydrogenase JF - RSC Advances N2 - α-hydroxy ketones (HK) and 1,2-diols are important building blocks for fine chemical synthesis. Here, we describe the R-selective 2,3-butanediol dehydrogenase from B. clausii DSM 8716ᵀ (BcBDH) that belongs to the metal-dependent medium chain dehydrogenases/reductases family (MDR) and catalyzes the selective asymmetric reduction of prochiral 1,2-diketones to the corresponding HK and, in some cases, the reduction of the same to the corresponding 1,2-diols. Aliphatic diketones, like 2,3-pentanedione, 2,3-hexanedione, 5-methyl-2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione are well transformed. In addition, surprisingly alkyl phenyl dicarbonyls, like 2-hydroxy-1-phenylpropan-1-one and phenylglyoxal are accepted, whereas their derivatives with two phenyl groups are not substrates. Supplementation of Mn²⁺ (1 mM) increases BcBDH's activity in biotransformations. Furthermore, the biocatalytic reduction of 5-methyl-2,3-hexanedione to mainly 5-methyl-3-hydroxy-2-hexanone with only small amounts of 5-methyl-2-hydroxy-3-hexanone within an enzyme membrane reactor is demonstrated. Y1 - 2020 U6 - http://dx.doi.org/10.1039/D0RA02066D SN - 2046-2069 VL - 10 SP - 12206 EP - 12216 PB - Royal Society of Chemistry (RSC) CY - Cambridge ER - TY - JOUR A1 - Bronder, Thomas A1 - Poghossian, Arshak A1 - Jessing, Max P. A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Surface regeneration and reusability of label-free DNA biosensors based on weak polyelectrolyte-modified capacitive field-effect structures JF - Biosensors and Bioelectronics Y1 - 2019 U6 - http://dx.doi.org/10.1016/j.bios.2018.11.019 SN - 0956-5663 VL - 126 SP - 510 EP - 517 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Arreola, Julio A1 - Oberländer, Jan A1 - Mätzkow, M. A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Surface functionalization for spore-based biosensors with organosilanes JF - Electrochimica Acta N2 - In the present work, surface functionalization of different sensor materials was studied. Organosilanes are well known to serve as coupling agent for biomolecules or cells on inorganic materials. 3-aminopropyltriethoxysilane (APTES) was used to attach microbiological spores time to an interdigitated sensor surface. The functionality and physical properties of APTES were studied on isolated sensor materials, namely silicon dioxide (SiO2) and platinum (Pt) as well as the combined material on sensor level. A predominant immobilization of spores could be demonstrated on SiO2 surfaces. Additionally, the impedance signal of APTES-functionalized biosensor chips has been investigated. Y1 - 2017 U6 - http://dx.doi.org/10.1016/j.electacta.2017.04.157 SN - 0013-4686 VL - 241 SP - 237 EP - 243 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Beging, Stefan A1 - Leinhos, Marcel A1 - Jablonski, Melanie A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Studying the spatially resolved immobilisation of enzymes on a capacitive field-effect structure by means of nano-spotting JF - Physica status solidi (a) Y1 - 2015 U6 - http://dx.doi.org/10.1002/pssa.201431891 SN - 1862-6319 VL - 212 IS - 6 SP - 1353 EP - 1358 PB - Wiley CY - Weinheim ER - TY - CHAP A1 - Welden, Melanie A1 - Severins, Robin A1 - Poghossian, Arshak A1 - Wege, Christina A1 - Siegert, Petra A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Studying the immobilization of acetoin reductase with Tobacco mosaic virus particles on capacitive field-effect sensors T2 - 2022 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN) N2 - A capacitive electrolyte-insulator-semiconductor (EISCAP) biosensor modified with Tobacco mosaic virus (TMV) particles for the detection of acetoin is presented. The enzyme acetoin reductase (AR) was immobilized on the surface of the EISCAP using TMV particles as nanoscaffolds. The study focused on the optimization of the TMV-assisted AR immobilization on the Ta 2 O 5 -gate EISCAP surface. The TMV-assisted acetoin EISCAPs were electrochemically characterized by means of leakage-current, capacitance-voltage, and constant-capacitance measurements. The TMV-modified transducer surface was studied via scanning electron microscopy. KW - Tobacco mosaic virus KW - acetoin KW - capacitive field-effect biosensor KW - enzyme immobilization Y1 - 2022 SN - 978-1-6654-5860-3 (Online) SN - 978-1-6654-5861-0 (Print) U6 - http://dx.doi.org/10.1109/ISOEN54820.2022.9789657 N1 - IEEE International Symposium on Olfaction and Electronic Nose (ISOEN), 29 May 2022 - 01 June 2022, Aveiro, Portugal. PB - IEEE ER - TY - JOUR A1 - Oberländer, Jan A1 - Jildeh, Zaid B. A1 - Kirchner, Patrick A1 - Wendeler, Luisa A1 - Bromm, Alexander A1 - Iken, Heiko A1 - Wagner, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Study of Interdigitated Electrode Arrays Using Experiments and Finite Element Models for the Evaluation of Sterilization Processes JF - Sensors N2 - In this work, a sensor to evaluate sterilization processes with hydrogen peroxide vapor has been characterized. Experimental, analytical and numerical methods were applied to evaluate and study the sensor behavior. The sensor set-up is based on planar interdigitated electrodes. The interdigitated electrode structure consists of 614 electrode fingers spanning over a total sensing area of 20 mm2. Sensor measurements were conducted with and without microbiological spores as well as after an industrial sterilization protocol. The measurements were verified using an analytical expression based on a first-order elliptical integral. A model based on the finite element method with periodic boundary conditions in two dimensions was developed and utilized to validate the experimental findings. Y1 - 2015 U6 - http://dx.doi.org/10.3390/s151026115 SN - 1424-8220 N1 - This article belongs to the Special Issue "Gas Sensors—Designs and Applications" VL - 15 IS - 10 SP - 26115 EP - 26127 PB - MDPI CY - Basel ER - TY - JOUR A1 - Simonis, A. A1 - Lüth, H. A1 - Wang, J. A1 - Schöning, Michael Josef T1 - Strategies of miniaturised reference electrodes integrated in a silicon-based „one chip“ pH sensor JF - Sensors. 3 (2003), H. 9 Y1 - 2003 SN - 1424-8220 SP - 330 EP - 339 ER - TY - JOUR A1 - Oberländer, Jan A1 - Kirchner, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Strategies in developing thin-film sensors for monitoring aseptic food processes : Theoretical considerations and investigations of passivation materials JF - Electrochimica Acta N2 - The sterilization of packages in aseptic food processes is highly significant to maintain a consumer-safe product with extended shelf-life. Today, the sterilization of food packages is predominantly accomplished by gaseous hydrogen peroxide (H2O2) in combination with heat. In order to monitor this sterilization process, calorimetric gas sensors as differential set-up of two platinum temperature sensors representing a catalytically active (additionally deposition of MnO2) and a passive segment have been recently developed. The temperature rise of the exothermic decomposition serves as an indicator of the present H2O2 concentration. In the present work, a theoretical approach considering the sensor’s thermochemistry and physical transport phenomena was formulated to evaluate the temperature rise based on the energy content of gaseous H2O2. In a further part of this work, three polymers have been analyzed with respect to their application as passivation materials. The examined polymers are photoresist SU-8, perfluoroalkoxy (PFA) and fluorinated ethylene propylene (FEP). Thermal analyses by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) have been conducted to determine the operation limits of the polymers. The overall chemical resistance and stability of the polymers against the harsh environmental conditions during the sterilization process have been examined by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.electacta.2015.06.126 SN - 0013-4686 VL - 183 SP - 130 EP - 136 PB - Elsevier CY - Amsterdam ER -