TY - JOUR A1 - Dantism, Shahriar A1 - Röhlen, Desiree A1 - Wagner, Torsten A1 - Wagner, P. A1 - Schöning, Michael Josef T1 - A LAPS-based differential sensor for parallelized metabolism monitoring of various bacteria JF - Sensors N2 - Monitoring the cellular metabolism of bacteria in (bio)fermentation processes is crucial to control and steer them, and to prevent undesired disturbances linked to metabolically inactive microorganisms. In this context, cell-based biosensors can play an important role to improve the quality and increase the yield of such processes. This work describes the simultaneous analysis of the metabolic behavior of three different types of bacteria by means of a differential light-addressable potentiometric sensor (LAPS) set-up. The study includes Lactobacillus brevis, Corynebacterium glutamicum, and Escherichia coli, which are often applied in fermentation processes in bioreactors. Differential measurements were carried out to compensate undesirable influences such as sensor signal drift, and pH value variation during the measurements. Furthermore, calibration curves of the cellular metabolism were established as a function of the glucose concentration or cell number variation with all three model microorganisms. In this context, simultaneous (bio)sensing with the multi-organism LAPS-based set-up can open new possibilities for a cost-effective, rapid detection of the extracellular acidification of bacteria on a single sensor chip. It can be applied to evaluate the metabolic response of bacteria populations in a (bio)fermentation process, for instance, in the biogas fermentation process. Y1 - 2019 U6 - http://dx.doi.org/10.3390/s19214692 SN - 1424-8220 VL - 19 IS - 21 PB - MDPI CY - Basel ER - TY - JOUR A1 - Karschuck, T. L. A1 - Filipov, Y. A1 - Bollella, P. A1 - Schöning, Michael Josef A1 - Katz, E. T1 - Not-XOR (NXOR) logic gate based on an enzyme-catalyzed reaction JF - International Journal of Unconventional Computing N2 - Enzyme-catalyzed reactions have been designed to mimic various Boolean logic gates in the general framework of unconventional biomolecular computing. While some of the logic gates, particularly OR, AND, are easy to realize with biocatalytic reactions and have been reported in numerous publications, some other, like NXOR, are very challenging and have not been realized yet with enzyme reactions. The paper reports on a novel approach to mimicking the NXOR logic gate using the bell-shaped enzyme activity dependent on pH values. Shifting pH from the optimum value to the acidic or basic values by using acid or base inputs (meaning 1,0 and 0,1 inputs) inhibits the enzyme reaction, while keeping the optimum pH (assuming 0,0 and 1,1 input combinations) preserves a high enzyme activity. The challenging part of the present approach is the selection of an enzyme with a well-demonstrated bell-shape activity dependence on the pH value. While many enzymes can satisfy this condition, we selected pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase as this enzyme has the optimum pH center-located on the pH scale allowing the enzyme activity change by the acidic and basic pH shift from the optimum value corresponding to the highest activity. The present NXOR gate is added to the biomolecular “toolbox” as a new example of Boolean logic gates based on enzyme reactions. Y1 - 2019 SN - 1548-7199 VL - 14 IS - 3-4 SP - 235 EP - 242 PB - Old City Publishing CY - Philadelphia ER - TY - JOUR A1 - Mennicken, Max A1 - Peter, Sophia Katharina A1 - Kaulen, Corinna A1 - Simon, Ulrich A1 - Karthäuser, Silvia T1 - Controlling the Electronic Contact at the Terpyridine/Metal Interface JF - The Journal of Physical Chemistry C Y1 - 2019 U6 - http://dx.doi.org/10.1021/acs.jpcc.9b05865 SN - 1932-7455 VL - 123 IS - 35 SP - 21367 EP - 21375 ER - TY - JOUR A1 - Arreola, Julio A1 - Keusgen, Michael A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - Combined calorimetric gas- and spore-based biosensor array for online monitoring and sterility assurance of gaseous hydrogen peroxide in aseptic filling machines JF - Biosensors and Bioelectronics Y1 - 2019 U6 - http://dx.doi.org/10.1016/j.bios.2019.111628 SN - 0956-5663 VL - 143 IS - 111628 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Jildeh, Zaid B. A1 - Kirchner, Patrick A1 - Baltes, Klaus A1 - Wagner, Patrick H. A1 - Schöning, Michael Josef T1 - Development of an in-line evaporation unit for the production of gas mixtures containing hydrogen peroxide – numerical modeling and experimental results JF - International Journal of Heat and Mass Transfer N2 - Hydrogen peroxide (H2O2) is a typical surface sterilization agent for packaging materials used in the pharmaceutical, food and beverage industries. We use the finite-elements method to analyze the conceptual design of an in-line thermal evaporation unit to produce a heated gas mixture of air and evaporated H2O2 solution. For the numerical model, the required phase-transition variables of pure H2O2 solution and of the aerosol mixture are acquired from vapor-liquid equilibrium (VLE) diagrams derived from vapor-pressure formulations. This work combines homogeneous single-phase turbulent flow with heat-transfer physics to describe the operation of the evaporation unit. We introduce the apparent heat-capacity concept to approximate the non-isothermal phase-transition process of the H2O2-containing aerosol. Empirical and analytical functions are defined to represent the temperature- and pressure-dependent material properties of the aqueous H2O2 solution, the aerosol and the gas mixture. To validate the numerical model, the simulation results are compared to experimental data on the heating power required to produce the gas mixture. This shows good agreement with the deviations below 10%. Experimental observations on the formation of deposits due to the evaporation of stabilized H2O2 solution fits the prediction made from simulation results. Y1 - 2019 U6 - http://dx.doi.org/10.1016/j.ijheatmasstransfer.2019.118519 SN - 0017-9310 VL - 143 PB - Elsevier CY - Amsterdam ER - TY - PAT A1 - Berger, Eric G. A1 - Biselli, Manfred A1 - Dinter, André A1 - Eisenkrätzer, Detlef A1 - Kiesewetter, André A1 - Zeng, Steffen T1 - Chinese-Hamster-Ovary-Zellen zur Produktion von Proteinen T1 - Chinese hamster ovary cells, useful for large-scale production of recombinant proteins, especially enzymes Y1 - 2000 N1 - DE000019847422C1 13.01.2000 EP000001121417A2 08.08.2001 WO002000022096A9 24.08.2000 SP - 1 EP - 6 ER - TY - JOUR A1 - Özsoylu, Dua A1 - Kizildag, Sefa A1 - Schöning, Michael Josef A1 - Wagner, Torsten T1 - Differential chemical imaging of extracellular acidification within microfluidic channels using a plasma-functionalized light-addressable potentiometric sensor (LAPS) JF - Physics in Medicine N2 - Extracellular acidification is a basic indicator for alterations in two vital metabolic pathways: glycolysis and cellular respiration. Measuring these alterations by monitoring extracellular acidification using cell-based biosensors such as LAPS plays an important role in studying these pathways whose disorders are associated with numerous diseases including cancer. However, the surface of the biosensors must be specially tailored to ensure high cell compatibility so that cells can represent more in vivo-like behavior, which is critical to gain more realistic in vitro results from the analyses, e.g., drug discovery experiments. In this work, O2 plasma patterning on the LAPS surface is studied to enhance surface features of the sensor chip, e.g., wettability and biofunctionality. The surface treated with O2 plasma for 30 s exhibits enhanced cytocompatibility for adherent CHO–K1 cells, which promotes cell spreading and proliferation. The plasma-modified LAPS chip is then integrated into a microfluidic system, which provides two identical channels to facilitate differential measurements of the extracellular acidification of CHO–K1 cells. To the best of our knowledge, it is the first time that extracellular acidification within microfluidic channels is quantitatively visualized as differential (bio-)chemical images. Y1 - 2020 U6 - http://dx.doi.org/10.1016/j.phmed.2020.100030 SN - 2352-4510 VL - 10 IS - 100030 PB - Elsevier CY - Amsterdam 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 - Falkenberg, Fabian A1 - Rahba, Jade A1 - Fischer, David A1 - Bott, Michael A1 - Bongaerts, Johannes A1 - Siegert, Petra T1 - Biochemical characterization of a novel oxidatively stable, halotolerant, and high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101T JF - FEBS Open Bio N2 - Halophilic and halotolerant microorganisms represent a promising source of salt-tolerant enzymes suitable for various biotechnological applications where high salt concentrations would otherwise limit enzymatic activity. Considering the current growing enzyme market and the need for more efficient and new biocatalysts, the present study aimed at the characterization of a high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101T. The protease gene was cloned and expressed in Bacillus subtilis DB104. The recombinant protease SPAO with 269 amino acids belongs to the subfamily of high-alkaline subtilisins. The biochemical characteristics of purified SPAO were analyzed in comparison with subtilisin Carlsberg, Savinase, and BPN'. SPAO, a monomer with a molecular mass of 27.1 kDa, was active over a wide range of pH 6.0–12.0 and temperature 20–80 °C, optimally at pH 9.0–9.5 and 55 °C. The protease is highly oxidatively stable to hydrogen peroxide and retained 58% of residual activity when incubated at 10 °C with 5% (v/v) H2O2 for 1 h while stimulated at 1% (v/v) H2O2. Furthermore, SPAO was very stable and active at NaCl concentrations up to 5.0 m. This study demonstrates the potential of SPAO for biotechnological applications in the future. KW - Alkalihalobacillus okhensis KW - detergent protease KW - halotolerant protease KW - high-alkaline subtilisin KW - oxidative stable protease Y1 - 2022 U6 - http://dx.doi.org/10.1002/2211-5463.13457 SN - 2211-5463 N1 - Corresponding author: Petra Siegert VL - 12 IS - 10 SP - 1729 EP - 1746 PB - Wiley CY - Hoboken, NJ ER - TY - JOUR A1 - Pourshahidi, Ali Mohammad A1 - Engelmann, Ulrich M. A1 - Offenhäusser, Andreas A1 - Krause, Hans-Joachim T1 - Resolving ambiguities in core size determination of magnetic nanoparticles from magnetic frequency mixing data JF - Journal of Magnetism and Magnetic Materials N2 - Frequency mixing magnetic detection (FMMD) has been widely utilized as a measurement technique in magnetic immunoassays. It can also be used for the characterization and distinction (also known as “colourization”) of different types of magnetic nanoparticles (MNPs) based on their core sizes. In a previous work, it was shown that the large particles contribute most of the FMMD signal. This leads to ambiguities in core size determination from fitting since the contribution of the small-sized particles is almost undetectable among the strong responses from the large ones. In this work, we report on how this ambiguity can be overcome by modelling the signal intensity using the Langevin model in thermodynamic equilibrium including a lognormal core size distribution fL(dc,d0,σ) fitted to experimentally measured FMMD data of immobilized MNPs. For each given median diameter d0, an ambiguous amount of best-fitting pairs of parameters distribution width σ and number of particles Np with R2 > 0.99 are extracted. By determining the samples’ total iron mass, mFe, with inductively coupled plasma optical emission spectrometry (ICP-OES), we are then able to identify the one specific best-fitting pair (σ, Np) one uniquely. With this additional externally measured parameter, we resolved the ambiguity in core size distribution and determined the parameters (d0, σ, Np) directly from FMMD measurements, allowing precise MNPs sample characterization. Y1 - 2022 U6 - http://dx.doi.org/10.1016/j.jmmm.2022.169969 SN - 0304-8853 VL - 563 IS - In progress, Art. No. 169969 PB - Elsevier CY - Amsterdam ER -