TY - JOUR A1 - Haeger, Gerrit A1 - Wirges, Jessika A1 - Tanzmann, Nicole A1 - Oyen, Sven A1 - Jolmes, Tristan A1 - Jaeger, Karl-Erich A1 - Schörken, Ulrich A1 - Bongaerts, Johannes A1 - Siegert, Petra T1 - Chaperone assisted recombinant expression of a mycobacterial aminoacylase in Vibrio natriegens and Escherichia coli capable of N-lauroyl-L-amino acid synthesis JF - Microbial Cell Factories N2 - Background Aminoacylases are highly promising enzymes for the green synthesis of acyl-amino acids, potentially replacing the environmentally harmful Schotten-Baumann reaction. Long-chain acyl-amino acids can serve as strong surfactants and emulsifiers, with application in cosmetic industries. Heterologous expression of these enzymes, however, is often hampered, limiting their use in industrial processes. Results We identified a novel mycobacterial aminoacylase gene from Mycolicibacterium smegmatis MKD 8, cloned and expressed it in Escherichia coli and Vibrio natriegens using the T7 overexpression system. The recombinant enzyme was prone to aggregate as inclusion bodies, and while V. natriegens Vmax™ could produce soluble aminoacylase upon induction with isopropyl β-d-1-thiogalactopyranoside (IPTG), E. coli BL21 (DE3) needed autoinduction with lactose to produce soluble recombinant protein. We successfully conducted a chaperone co-expression study in both organisms to further enhance aminoacylase production and found that overexpression of chaperones GroEL/S enhanced aminoacylase activity in the cell-free extract 1.8-fold in V. natriegens and E. coli. Eventually, E. coli ArcticExpress™ (DE3), which co-expresses cold-adapted chaperonins Cpn60/10 from Oleispira antarctica, cultivated at 12 °C, rendered the most suitable expression system for this aminoacylase and exhibited twice the aminoacylase activity in the cell-free extract compared to E. coli BL21 (DE3) with GroEL/S co-expression at 20 °C. The purified aminoacylase was characterized based on hydrolytic activities, being most stable and active at pH 7.0, with a maximum activity at 70 °C, and stability at 40 °C and pH 7.0 for 5 days. The aminoacylase strongly prefers short-chain acyl-amino acids with smaller, hydrophobic amino acid residues. Several long-chain amino acids were fairly accepted in hydrolysis as well, especially N-lauroyl-L-methionine. To initially evaluate the relevance of this aminoacylase for the synthesis of N-acyl-amino acids, we demonstrated that lauroyl-methionine can be synthesized from lauric acid and methionine in an aqueous system. Conclusion Our results suggest that the recombinant enzyme is well suited for synthesis reactions and will thus be further investigated. KW - Acyl-amino acids KW - Inclusion bodies KW - Chaperone co-expression KW - Vibrio natriegens KW - Aminoacylase Y1 - 2023 U6 - http://dx.doi.org/10.1186/s12934-023-02079-1 SN - 1475-2859 N1 - Corresponding author: Petra Siegert IS - 22 SP - Article number: 77 (2023) PB - Springer Nature ER - TY - JOUR A1 - Hanrath, Wilhelm T1 - Character tables of some factor groups of space groups JF - Perfect groups / Derek F. Holt and W. Plesken Y1 - 1989 SN - 0-19-853559-7 SP - 357 EP - 359 PB - Clarendon Press CY - Oxford ER - TY - JOUR A1 - Schwarzer, Klemens A1 - Silva, Maria Eugenia Vieira da T1 - Characterisation and design methods of solar cookers / Schwarzer, Klemens ; Silva, Maria Eugenia Vieira da JF - Solar energy. 82 (2008), H. 2 Y1 - 2008 SN - 0038-092X SP - 157 EP - 163 ER - TY - CHAP A1 - Reisert, Steffen A1 - Geissler, H. A1 - Flörke, R. A1 - Weiler, C. A1 - Wagner, P. A1 - Schöning, Michael Josef ED - Abdelghani, Adnane ED - Schöning, Michael Josef T1 - Characterisation of aseptic sterilisation processes using an electronic nose T2 - Nanoscale Science and Technology (NS&T´12) : Proceedings Book Humboldt Kolleg ; Tunisia, 17-19 March, 2012 Y1 - 2012 SP - 45 EP - 45 ER - TY - JOUR A1 - Reisert, Steffen A1 - Geissler, Hanno A1 - Flörke, Rudolf A1 - Weiler, Christian A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Characterisation of aseptic sterilisation processes using an electronic nose JF - International journal of nanotechnology Y1 - 2013 SN - 1475-7435 (Print) 7141-8151 (Online) VL - Vol. 10 IS - No. 5-7 SP - 470 EP - 484 PB - Inderscience Enterprises CY - Genève ER - TY - JOUR A1 - Abouzar, Maryam H. A1 - Poghossian, Arshak A1 - Razavi, A. A1 - Williams, O. A. A1 - Bijnens, N. A1 - Wagner, P. A1 - Schöning, Michael Josef T1 - Characterisation of capacitive field-effect sensors with a nanocrystalline-diamond film as transducer material for multi-parameter sensing JF - Biosensors and Bioelectronics. 24 (2009), H. 5 Y1 - 2009 SN - 0956-5663 N1 - Selected Papers from the Tenth World Congress on Biosensors Shangai, China, May 14-16, 2008 ; Zeitschrift früher u.d.T. : Biosensors SP - 1298 EP - 1304 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kirchner, Patrick A1 - Reisert, Steffen A1 - Pütz, Patrick A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Characterisation of polymeric materials as passivation layer for calorimetric H2O2 gas sensors JF - Physica Status Solidi (a) N2 - Calorimetric gas sensors for monitoring the H₂O₂ concentration at elevated temperatures in industrial sterilisation processes have been presented in previous works. These sensors are built up in form of a differential set-up of a catalytically active and passive temperature-sensitive structure. Although, various types of catalytically active dispersions have been studied, the passivation layer has to be established and therefore, chemically as well as physically characterised. In the present work, fluorinated ethylene propylene (FEP), perfluoralkoxy (PFA) and epoxy-based SU-8 photoresist as temperature-stable polymeric materials have been investigated for sensor passivation in terms of their chemical inertness against H₂O₂, their hygroscopic properties as well as their morphology. The polymeric materials were deposited via spin-coating on the temperature-sensitive structure, wherein spin-coated FEP and PFA show slight agglomerates. However, they possess a low absorption of humidity due to their hydrophobic surface, whereas the SU-8 layer has a closed surface but shows a slightly higher absorption of water. All of them were inert against gaseous H₂O₂ during the characterisation in H₂O₂ atmosphere that demonstrates their suitability as passivation layer for calorimetric H₂O₂ gas sensors. Y1 - 2012 U6 - http://dx.doi.org/10.1002/pssa.201100773 SN - 1862-6319 VL - 209 IS - 5 SP - 859 EP - 863 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Schroth, P. A1 - Lüth, H. A1 - Hummel, Hans E. A1 - Schütz, S. A1 - Schöning, Michael Josef T1 - Characterising an insect antenna as a receptor for a biosensor by means of impedance spectroscopy JF - Scaling down in electrochemistry : electrochemical micro- and nanosystem technology ; proceedings of the 3rd International Symposium on Electrochemical Microsystem Technologies, Garmisch-Patenkirchen, Germany, 11 - 15 September 2000 / ed. by J. W. Schultz Y1 - 2001 SN - 0-08-044014-2 SP - 293 EP - 297 PB - Elsevier [u.a.] CY - Amsterdam [u.a.] ER - TY - BOOK A1 - Gottschalk, Sandra A1 - Janz, Norbert A1 - Rennings, Klaus T1 - Characteristics and Performance of Eco-Innovative Firms in the German Service Sector Y1 - 1998 ER - TY - JOUR A1 - Lassonczyk, Beate T1 - Characteristics of a fossil soil developed on the basement complex in the northeast Somalia JF - Berliner geowissenschaftliche Abhandlungen / Reihe A, Geologie und Paläontologie / hrsg. von d. Geowissenschaftlichen Instituten der Freien u. d. Technischen Universität Berlin. 120 A (1990) Y1 - 1990 SN - 0172-8784 SP - 713 EP - 718 ER - TY - JOUR A1 - Helsper, Christoph A1 - Mölter, W. T1 - Characteristics of a Nebulizer with Cyclone Preseparator / Mölter, W. ; Helsper, C. JF - Aerosols, their generation, behaviour and applications. Annual Conference of the Aerosol Society / Aerosol Society (UK) ; 5. Y1 - 1991 SP - 89 EP - 94 CY - Loughborough ER - TY - CHAP A1 - Oertel, Mario A1 - Bung, Daniel B. T1 - Characteristics of cross-bar block ramp flows T2 - Hydraulic structures into the 21st century : 4th IAHR International Symposium on Hydraulic Structures : 9.-11.2.2012, Porto Y1 - 2012 SN - 978-989-8509-01-7 ER - TY - CHAP A1 - Roth, J. A1 - Möhring, S. A1 - Tippkötter, Nils T1 - Characterization and evaluation of lignocellulosic biomass 130 hydrolysates for ABE fermentation T2 - New frontiers of biotech-processes (Himmelfahrtstagung) : 02-04 May 2016, Rhein-Mosel-Halle, Koblenz/Germany Y1 - 2016 SP - 130 PB - DECHEMA CY - Frankfurt am Main ER - TY - JOUR A1 - Mukherjee, Krishnendu A1 - Prahl, Ulrich A1 - Bleck, Wolfgang A1 - Reisgen, Uwe A1 - Schleser, Markus A1 - Abdurakhmanov, Aydemir T1 - Characterization and modelling techniques for gas metal arc welding of DP 600 sheet steels JF - Materialwissenschaft und Werkstofftechnik N2 - The objectives of the present work are to characterize the Gas Metal Arc Welding process of DP 600 sheet steel and to summarize the modelling techniques. The time-temperature evolution during the welding cycle was measured experimentally and modelled with the softwaretool SimWeld. To model the phase transformations during the welding cycle dilatometer tests were done to quantify the parameters for phase field modelling by MICRESS®. The important input parameters are interface mobility, nucleation density, etc. A contribution was made to include austenite to bainite transformation in MICRESS®. This is useful to predict the microstructure in the fast cooling segments. The phase transformation model is capable to predict the microstructure along the heating and cooling cycles of welding. Tensile tests have shown the evidence of failure at the heat affected zone, which has the ferrite-tempered martensite microstructure. Y1 - 2010 U6 - http://dx.doi.org/10.1002/mawe.201000692 SN - 1521-4052 VL - 41 IS - 11 SP - 972 EP - 983 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Holtrup, S. A1 - Sadeghfam, Arash A1 - Heuermann, Holger A1 - Awakowicz, P. T1 - Characterization and optimization technique for microwave-driven high-intensity discharge lamps using hot S-parameters JF - IEEE transactions on microwave theories and techniques N2 - High-intensity discharge lamps can be driven by radio-frequency signals in the ISM frequency band at 2.45 GHz, using a matching network to transform the impedance of the plasma to the source impedance. To achieve an optimal operating condition, a good characterization of the lamp in terms of radio frequency equivalent circuits under operating conditions is necessary, enabling the design of an efficient matching network. This paper presents the characterization technique for such lamps and presents the design of the required matching network. For the characterization, a high-intensity discharge lamp was driven by a monofrequent large signal at 2.45 GHz, whereas a frequency sweep over 300 MHz was performed across this signal to measure so-called small-signal hot S-parameters using a vector network analyzer. These parameters are then used as an equivalent load in a circuit simulator to design an appropriate matching network. Using the measured data as a black-box model in the simulation results in a quick and efficient method to simulate and design efficient matching networks in spite of the complex plasma behavior. Furthermore, photometric analysis of high-intensity discharge lamps are carried out, comparing microwave operation to conventional operation. Y1 - 2014 U6 - http://dx.doi.org/10.1109/TMTT.2014.2342652 SN - 0018-9480 VL - 62 IS - 10 SP - 2471 EP - 2480 PB - IEEE CY - New York ER - TY - JOUR A1 - Selmer, Thorsten A1 - Kim, Jihoe A1 - Darley, Daniel A1 - Buckel, Wolfgang T1 - Characterization of (R)-2-hydroxyisocaproate dehydrogenase and a family III coenzyme A transferase involved in reduction of L-leucine to isocaproate by Clostridium difficile / Kim, J. ; Darley, D. ; Selmer, T. ; Buckel, W. JF - Applied and Environmental Microbiology. 72 (2006), H. 9 Y1 - 2006 SN - 0099-2240 N1 - PMID: 16957230 SP - 6062 EP - 6069 ER - TY - JOUR A1 - Jossek, Ralf A1 - Bongaerts, Johannes A1 - Sprenger, Georg A. T1 - Characterization of a new feedback-resistant 3-deoxy-D-arabinoheptulosonate 7-phosphate synthase AroF of Escherichia coli JF - FEMS microbiology letters Y1 - 2001 SN - 1574-6968 VL - Vol. 202 IS - Iss. 1 SP - 145 EP - 148 ER - TY - JOUR A1 - Schusser, Sebastian A1 - Poghossian, Arshak A1 - Bäcker, Matthias A1 - Leinhos, Marcel A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Characterization of biodegradable polymers with capacitive field-effect sensors JF - Sensors and actuators B: Chemical N2 - In vitro studies of the degradation kinetic of biopolymers are essential for the design and optimization of implantable biomedical devices. In the presented work, a field-effect capacitive sensor has been applied for the real-time and in situ monitoring of degradation processes of biopolymers for the first time. The polymer-covered field-effect sensor is, in principle, capable to detect any changes in bulk, surface and interface properties of the polymer induced by degradation processes. The feasibility of this approach has been experimentally proven by using the commercially available biomedical polymer poly(D,L-lactic acid) (PDLLA) as a model system. PDLLA films of different thicknesses were deposited on the Ta₂O₅-gate surface of the field-effect structure from a polymer solution by means of spin-coating method. The polymer-modified field-effect sensors have been characterized by means of capacitance–voltage and impedance-spectroscopy method. The degradation of the PDLLA was accelerated by changing the degradation medium from neutral (pH 7.2) to alkaline (pH 9) condition, resulting in drastic changes in the capacitance and impedance spectra of the polymer-modified field-effect sensor. KW - Impedance spectroscopy KW - C–V method KW - Real-time monitoring KW - Poly(d,l-lacticacid) KW - (Bio)degradation KW - Field-effect sensor Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2012.07.099 SN - 0925-4005 N1 - Part of special issue "Selected Papers from the 14th International Meeting on Chemical Sensors" VL - 187 SP - 2 EP - 7 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mukherjee, Krishnendu A1 - Ramazani, Ali A1 - Yang, Li A1 - Prahl, Ulrich A1 - Bleck, Wolfgang A1 - Reisgen, Uwe A1 - Schleser, Markus A1 - Abdurakhmanov, Aydemir T1 - Characterization of gas metal arc welded hot rolled DP600 steel JF - Steel research international Y1 - 2011 SN - 1869-344X (E-Book); 1611-3683 (Print) VL - Vol. 82 IS - Iss. 12 SP - 1408 EP - 1416 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Förster, Arnold A1 - Morvic, M. A1 - Betko, J. A1 - Novak, J. T1 - Characterization of low-temperature GaAs by conductivity, Hall effect and magnetoresistance measurements. Morvic, M., Betko, J.; Novak, J.; Förster, A.; Kordos, P. JF - 2nd Symposium on Non-Stoichiometric III-V Compounds : [4th - 6th October 1999, Erlangen] / [ed. by T. Marek ...] Friedrich-Alexander-Universität Erlangen-Nürnberg Y1 - 1999 SN - 3-932392-19-1 N1 - Symposium on Non-Stoichiometric III-V Compounds <2, 1999, Erlangen> SP - 79 EP - 85 PB - Lehrstuhl für Mikrocharakterisierung CY - Erlangen ER -