@article{Alexopoulos2012, author = {Alexopoulos, Spiros}, title = {Biogas systems: basics, biogas multifunction, principle of fermentation and hybrid application with a solar tower for the treatment of waste animal manure}, series = {Journal of Engineering Science and Technology Review}, volume = {5}, journal = {Journal of Engineering Science and Technology Review}, number = {4}, publisher = {Kavala Institute of Technology}, address = {Kavala}, issn = {1791-2377}, pages = {48 -- 55}, year = {2012}, abstract = {Two of the main environmental problems of today's society are the continuously increasing production of organic wastes as well as the increase of carbon dioxide in the atmosphere and the related green house effect. A way to solve these problems is the production of biogas. Biogas is a combustible gas consisting of methane, carbon dioxide and small amounts of other gases and trace elements. Production of biogas through anaerobic digestion of animal manure and slurries as well as of a wide range of digestible organic wastes and agricultural residues, converts these substrates into electricity and heat and offers a natural fertiliser for agriculture. The microbiological process of decomposition of organic matter, in the absence of oxygen takes place in reactors, called digesters. Biogas can be used as a fuel in a gas turbine or burner and can be used in a hybrid solar tower system offering a solution for waste treatment of agricultural and animal residues. A solar tower system consists of a heliostat field, which concentrates direct solar irradiation on an open volumetric central receiver. The receiver heats up ambient air to temperatures of around 700°C. The hot air's heat energy is transferred to a steam Rankine cycle in a heat recovery steam generator (HRSG). The steam drives a steam turbine, which in turn drives a generator for producing electricity. In order to increase the operational hours of a solar tower power plant, a heat storage system and/ or hybridization may be considered. The advantage of solar-fossil hybrid power plants, compared to solar-only systems, lies in low additional investment costs due to an adaptable solar share and reduced technical and economical risks. On sunny days the hybrid system operates in a solar-only mode with the central receiver and on cloudy days and at night with the gas turbine only. As an alternative to methane gas, environmentally neutral biogas can be used for operating the gas turbine. Hence, the hybrid system is operated to 100\% from renewable energy sources}, language = {en} } @article{HasanKeilStaatetal.2012, author = {Hasan, Istabrak and Keil, Ludger and Staat, Manfred and Wahl, Gerhard and Bourauel, Christoph}, title = {Determination of the frictional coefficient of the implant-antler interface : experimental approach}, series = {Biomedical Engineering / Biomedizinische Technik}, volume = {57}, journal = {Biomedical Engineering / Biomedizinische Technik}, number = {5}, publisher = {De Gruyter}, address = {Berlin}, issn = {1862-278X}, pages = {359 -- 363}, year = {2012}, abstract = {The similar bone structure of reindeer antler to human bone permits studying the osseointegration of dental implants in the jawbone. As the friction is one of the major factors that have a significant influence on the initial stability of immediately loaded dental implants, it is essential to define the frictional coefficient of the implant-antler interface. In this study, the kinetic frictional forces at the implant-antler interface were measured experimentally using an optomechanical setup and a stepping motor controller under different axial loads and sliding velocities. The corresponding mean values of the static and kinetic frictional coefficients were within the range of 0.5-0.7 and 0.3-0.5, respectively. An increase in the frictional forces with increasing applied axial loads was registered. The measurements showed an evidence of a decrease in the magnitude of the frictional coefficient with increasing sliding velocity. The results of this study provide a considerable assessment to clarify the suitable frictional coefficient to be used in the finite element contact analysis of antler specimens.}, language = {en} } @article{ReisgenSchleserAbdurakhmanovetal.2012, author = {Reisgen, Uwe and Schleser, Markus and Abdurakhmanov, Aydemir and Gumenyuk, Andrey}, title = {Measuring of plasma properties induced by non-vacuum electron beam welding}, series = {Physics of plasma}, volume = {19}, journal = {Physics of plasma}, number = {1}, publisher = {AIP Publishing}, address = {Melville, NY}, issn = {1089-7674 (E-Journal); 1070-664X (Print)}, doi = {10.1063/1.3675874}, year = {2012}, abstract = {Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of high-power electron beams. The key element of the method is a rotating thin tungsten wire, which intersects the beam transversely on its axis and collects part of the current by itself. The signals, which are registered in the DIABEAM as a voltage, were taken in the form of amplitude. The conversion of the probe current into the distribution along the beam radius was realised using the Abel's method. A voltage-current characteristic was built for the beam current. The local electron density as well as the electron temperature, the floating potential and the plasma potential were measured and calculated by means of this characteristic.}, language = {en} } @article{ReisgenOlschokJakobsetal.2012, author = {Reisgen, Uwe and Olschok, Simon and Jakobs, Stefan and Schleser, Markus and Mokrov, Oleg and Rossiter, Eduardo}, title = {Laser beam submerged arc hybrid welding}, series = {Physics procedia}, volume = {39}, journal = {Physics procedia}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1875-3892}, doi = {10.1016/j.phpro.2012.10.016}, pages = {75 -- 83}, year = {2012}, abstract = {The laser beam-submerged arc hybrid welding method originates from the knowledge that, with increasing penetration depth, the laser beam process has a tendency to pore formation in the lower weld regions. The coupling with the energy-efficient submerged-arc process improves degassing and reduces the tendency to pore formation. The high deposition rate of the SA process in combination with the laser beam process offers, providing the appropriate choice of weld preparation, the possibility of welding plates with a thickness larger than 20° mm in a single pass, and also of welding thicker plates with the double-sided single pass technique.}, language = {en} } @article{ScheikSchleserReisgen2012, author = {Scheik, Sven and Schleser, Markus and Reisgen, Uwe}, title = {Thermisches Direktf{\"u}gen von Metall und Kusntstoff: eine Alternative zur Klebtechnik}, series = {Adh{\"a}sion : Kleben \& Dichten}, volume = {56}, journal = {Adh{\"a}sion : Kleben \& Dichten}, number = {11}, publisher = {Springer Vieweg}, address = {Wiesbaden}, issn = {0001-8198 (E-Journal); 0001-8198 (Print)}, doi = {10.1007/s35145-012-0005-x}, pages = {36 -- 40}, year = {2012}, abstract = {Im Rahmen des Exzellenzclusters „Integrative Produktionstechnik f{\"u}r Hochlohnl{\"a}nder" der RWTHAachen University werden derzeit alternative Verfahren zur Herstellung von Metall/Kunststoff- Verbindungen untersucht. Eines davon ist das thermische Direktf{\"u}gen, das eine stoffschl{\"u}ssige Verbindung zwischen Kunststoff und Metall erm{\"o}glicht und ohne die Verwendung von Klebstoffen, Haftvermittlern oder mechanischen Verbindungshilfen auskommt.}, language = {de} } @article{SchifferFerreinLakemeyer2012, author = {Schiffer, Stefan and Ferrein, Alexander and Lakemeyer, Gerhard}, title = {Caesar: an intelligent domestic service robot}, series = {Intelligent service robotics}, volume = {5}, journal = {Intelligent service robotics}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {1861-2776}, doi = {10.1007/s11370-012-0118-y}, pages = {259 -- 276}, year = {2012}, abstract = {In this paper we present CAESAR, an intelligent domestic service robot. In domestic settings for service robots complex tasks have to be accomplished. Those tasks benefit from deliberation, from robust action execution and from flexible methods for human-robot interaction that account for qualitative notions used in natural language as well as human fallibility. Our robot CAESAR deploys AI techniques on several levels of its system architecture. On the low-level side, system modules for localization or navigation make, for instance, use of path-planning methods, heuristic search, and Bayesian filters. For face recognition and human-machine interaction, random trees and well-known methods from natural language processing are deployed. For deliberation, we use the robot programming and plan language READYLOG, which was developed for the high-level control of agents and robots; it allows combining programming the behaviour using planning to find a course of action. READYLOG is a variant of the robot programming language Golog. We extended READYLOG to be able to cope with qualitative notions of space frequently used by humans, such as "near" and "far". This facilitates human-robot interaction by bridging the gap between human natural language and the numerical values needed by the robot. Further, we use READYLOG to increase the flexible interpretation of human commands with decision-theoretic planning. We give an overview of the different methods deployed in CAESAR and show the applicability of a system equipped with these AI techniques in domestic service robotics}, language = {en} } @article{BassamHeschelerTemizArtmannetal.2012, author = {Bassam, Rasha and Hescheler, J{\"u}rgen and Temiz Artmann, Ayseg{\"u}l and Artmann, Gerhard and Digel, Ilya}, title = {Effects of spermine NONOate and ATP on the thermal stability of hemoglobin}, series = {BMC Biophysics}, volume = {5}, journal = {BMC Biophysics}, publisher = {BioMed Central}, address = {London}, issn = {2046-1682}, doi = {10.1186/2046-1682-5-16}, year = {2012}, abstract = {Background Minor changes in protein structure induced by small organic and inorganic molecules can result in significant metabolic effects. The effects can be even more profound if the molecular players are chemically active and present in the cell in considerable amounts. The aim of our study was to investigate effects of a nitric oxide donor (spermine NONOate), ATP and sodium/potassium environment on the dynamics of thermal unfolding of human hemoglobin (Hb). The effect of these molecules was examined by means of circular dichroism spectrometry (CD) in the temperature range between 25°C and 70°C. The alpha-helical content of buffered hemoglobin samples (0.1 mg/ml) was estimated via ellipticity change measurements at a heating rate of 1°C/min. Results Major results were: 1) spermine NONOate persistently decreased the hemoglobin unfolding temperature T u irrespectively of the Na + /K + environment, 2) ATP instead increased the unfolding temperature by 3°C in both sodium-based and potassium-based buffers and 3) mutual effects of ATP and NO were strongly influenced by particular buffer ionic compositions. Moreover, the presence of potassium facilitated a partial unfolding of alpha-helical structures even at room temperature. Conclusion The obtained data might shed more light on molecular mechanisms and biophysics involved in the regulation of protein activity by small solutes in the cell.}, language = {en} } @article{Timme2012, author = {Timme, Michael}, title = {Die Reichweite der "werdenden" Wohnungseigent{\"u}mergemeinschaft gegen{\"u}ber dem Zweiterwerb}, series = {Monatsschrift f{\"u}r Deutsches Recht : MdR}, volume = {2012}, journal = {Monatsschrift f{\"u}r Deutsches Recht : MdR}, number = {18}, publisher = {Verlag Dr. Otto Schmidt}, address = {K{\"o}ln}, issn = {0340-1812}, doi = {10.9785/ovs-mdtr-2012-1069}, pages = {1068 -- 1071}, year = {2012}, abstract = {Mit einer aktuellen Entscheidung hat der BGH, Urt. v. 11.5.2012 - V ZR 196/11, MDR 2012, 958 seine Rechtsprechung v. 5.6.2008 - V ZB 85/07 zur Entstehungsphase einer Wohnungseigent{\"u}mergemeinschaft fortgef{\"u}hrt. In dieser Entscheidung sieht der BGH die Erwerber von Wohnungseigentum als Kostenschuldner gem. \S 16 Abs. 2 WEG an, obwohl diese noch nicht im Grundbuch eingetragen sind. Eine andere Rechtslage besteht beim sog. Zweiterwerb. Die Abgrenzung von Erstund Zweierwerb ist aufgrund der v{\"o}llig unterschiedlichen Rechtsfolgen f{\"u}r die Praxis von großer Bedeutung.}, language = {de} } @inproceedings{HoeflingSchirraSpohretal.2013, author = {Hoefling, J. and Schirra, Julian and Spohr, A. and Sch{\"a}fer, Daniel}, title = {Induced drag computation with wake model schemes for highly non-planar wing systems}, series = {Deutscher Luft- und Raumfahrtkongress 2013 : 10.9. - 12.9.2013, Stuttgart}, booktitle = {Deutscher Luft- und Raumfahrtkongress 2013 : 10.9. - 12.9.2013, Stuttgart}, publisher = {Dt. Ges. f{\"u}r Luft- und Raumfahrt}, address = {Bonn}, organization = {Deutscher Luft- und Raumfahrtkongress <62, 2013, Stuttgart>}, pages = {1 -- 10}, year = {2013}, language = {en} } @article{Grotendorst2012, author = {Grotendorst, Johannes}, title = {Supercomputer programmieren - ein besonderes Studienangebot in J{\"u}lich}, series = {Junge Wissenschaft}, volume = {27}, journal = {Junge Wissenschaft}, number = {94}, publisher = {Verlag Junge Wissenschaft}, address = {D{\"u}sseldorf}, isbn = {0179-8529}, pages = {12 -- 14}, year = {2012}, language = {de} } @article{Grotendorst2012, author = {Grotendorst, Johannes}, title = {IAS Winter School: Hierarchical Methods for Dynamics in Complex Molecular Systems}, series = {Innovatives Supercomputing in Deutschland : inSiDE}, volume = {10}, journal = {Innovatives Supercomputing in Deutschland : inSiDE}, pages = {104 -- 1}, year = {2012}, language = {en} } @inproceedings{BeckerHoefkenSchuetzetal.2016, author = {Becker, Sebastian and H{\"o}fken, Hans-Wilhelm and Sch{\"u}tz, Philip and Schuba, Marko}, title = {IT-forensische Erkennung modifizierter Android-Apps}, series = {Proceedings of DACH Security 2016, Klagenfurt, Austria, September 2016}, booktitle = {Proceedings of DACH Security 2016, Klagenfurt, Austria, September 2016}, editor = {Schartner, P.}, pages = {120 -- 125}, year = {2016}, abstract = {Malware auf Smartphones ist ein Problem, dem auch Strafverfolgungsbeh{\"o}rden immer h{\"a}ufiger gegen{\"u}berstehen. Insbesondere Telefone, bei denen potentiell schadhafte Apps zu einem finanziellen Schaden gef{\"u}hrt haben, finden sich auf den Schreibtischen der Polizei wieder. Dabei m{\"u}ssen die Ermittler m{\"o}glichst schnell und gezielt erkennen k{\"o}nnen, ob eine App tats{\"a}chlich schadhaft manipuliert wurde, was manipuliert wurde und mit wem die App kommuniziert. Klassische Malware-Erkennungsverfahren helfen zwar bei der generellen Erkennung schadhafter Software, sind aber f{\"u}r die polizeiliche Praxis nicht geeignet. Dieses Paper stellt ein Programm vor, welches gerade die forensischen Fragestellungen ber{\"u}cksichtigt und so f{\"u}r den Einsatz in der Strafverfolgung in Frage kommt.}, language = {de} } @article{MansurovJandosovKerimkulovaetal.2014, author = {Mansurov, Zulkhair A. and Jandosov, J. M. and Kerimkulova, Almagul R. and Azat, Seitkhan and Zhubanova, Azhar Achmet and Digel, Ilya and Savistkaya, I. S. and Akimbekov, Nuraly S. and Kistaubaeva, A. S.}, title = {Nanostructured carbon materials for biomedical use}, series = {Eurasian chemico-technological journal : quarterly journal of the International Higher Education Academy of Sciences}, volume = {15 (2013)}, journal = {Eurasian chemico-technological journal : quarterly journal of the International Higher Education Academy of Sciences}, number = {3}, publisher = {Institute of Combustion Problems}, address = {Almaty}, issn = {1562-3920}, doi = {10.18321/ectj224}, pages = {209 -- 217}, year = {2014}, abstract = {One of the priority trends of carbon nanotechnology is creation of nanocomposite systems. Such carbon nanostructured composites were produced using - raw materials based on the products of agricultural waste, such as grape stones, apricot stones, rice husk. These products have a - wide spectrum of application and can be obtained in large quantities. The Institute of Combustion Problems has carried out the work on synthesis of the nanostructured carbon sorbents for multiple applications including the field of biomedicine. The article presents the data on the synthesis and physico-chemical properties of carbonaceous sorbents using physicochemical methods of investigation: separation and purification of biomolecules; isolation of phytohormone - fusicoccin; adsorbent INGO-1 in the form of an adsorption column for blood detoxification, oral (entero) sorbent - INGO-2; the study of efferent and probiotic properties and sorption activity in regard to the lipopolysaccharide (LPS), new biocomposites - based on carbonized rice husk (CRH) and cellular microorganisms; the use of CRH in wound treatment. A new material for blood detoxication (INGO-1) has been obtained. Adsorption of p-cresyl sulfate and indoxyl sulfate has shown that active carbon adsorbent can remove clinically significant level of p-cresyl sulfate and indoxyl sulfate from human plasma. Enterosorbent INGO-2 possesses high adsorption activity in relation to Gram-negative bacteria and their endotoxins. INGO-2 slows down the growth of conditionally pathogenic microorganisms, without having a negative effect on bifido and lactobacteria. The use of enterosorbent INGO-2 for sorption therapy may provide a solution to a complex problem - detoxication of the digestive tract and normalization of the intestinal micro ecology. The immobilized probiotic called "Riso-lact" was registered at the Ministry of Health of the Republic of Kazakhstan as a biologically active food additive. The developed technology is patented and provides production of the medicine in the form of freeze-dried biomass immobilized in vials.}, language = {en} } @inproceedings{SchubaHoefkenLinzbach2022, author = {Schuba, Marko and H{\"o}fken, Hans-Wilhelm and Linzbach, Sophie}, title = {An ICS Honeynet for Detecting and Analyzing Cyberattacks in Industrial Plants}, series = {2021 International Conference on Electrical, Computer and Energy Technologies (ICECET)}, booktitle = {2021 International Conference on Electrical, Computer and Energy Technologies (ICECET)}, publisher = {IEEE}, isbn = {978-1-6654-4231-2}, doi = {10.1109/ICECET52533.2021.9698746}, pages = {6 Seiten}, year = {2022}, abstract = {Cybersecurity of Industrial Control Systems (ICS) is an important issue, as ICS incidents may have a direct impact on safety of people or the environment. At the same time the awareness and knowledge about cybersecurity, particularly in the context of ICS, is alarmingly low. Industrial honeypots offer a cheap and easy to implement way to raise cybersecurity awareness and to educate ICS staff about typical attack patterns. When integrated in a productive network, industrial honeypots may not only reveal attackers early but may also distract them from the actual important systems of the network. Implementing multiple honeypots as a honeynet, the systems can be used to emulate or simulate a whole Industrial Control System. This paper describes a network of honeypots emulating HTTP, SNMP, S7communication and the Modbus protocol using Conpot, IMUNES and SNAP7. The nodes mimic SIMATIC S7 programmable logic controllers (PLCs) which are widely used across the globe. The deployed honeypots' features will be compared with the features of real SIMATIC S7 PLCs. Furthermore, the honeynet has been made publicly available for ten days and occurring cyberattacks have been analyzed}, language = {en} } @article{LagemaatBreukelsVosetal.2016, author = {Lagemaat, Miriam W. and Breukels, Vincent and Vos, Eline K. and Kerr, Adam B. and Uden, Mark J. van and Orzada, Stephan and Bitz, Andreas and Maas, Marnix C. and Scheenen, Tom W. J.}, title = {¹H MR spectroscopic imaging of the prostate at 7T using spectral-spatial pulses}, series = {Magnetic Resonance in Medicine}, volume = {75}, journal = {Magnetic Resonance in Medicine}, number = {3}, publisher = {International Society for Magnetic Resonance in Medicine}, issn = {1522-2594}, doi = {10.1002/mrm.25569}, pages = {933 -- 945}, year = {2016}, abstract = {Purpose To assess the feasibility of prostate ¹H MR spectroscopic imaging (MRSI) using low-power spectral-spatial (SPSP) pulses at 7T, exploiting accurate spectral selection and spatial selectivity simultaneously. Methods A double spin-echo sequence was equipped with SPSP refocusing pulses with a spectral selectivity of 1 ppm. Three-dimensional prostate ¹H-MRSI at 7T was performed with the SPSP-MRSI sequence using an 8-channel transmit array coil and an endorectal receive coil in three patients with prostate cancer and in one healthy subject. No additional water or lipid suppression pulses were used. Results Prostate ¹H-MRSI could be obtained well within specific absorption rate (SAR) limits in a clinically feasible time (10 min). Next to the common citrate signals, the prostate spectra exhibited high spermine signals concealing creatine and sometimes also choline. Residual lipid signals were observed at the edges of the prostate because of limitations in spectral and spatial selectivity. Conclusion It is possible to perform prostate ¹H-MRSI at 7T with a SPSP-MRSI sequence while using separate transmit and receive coils. This low-SAR MRSI concept provides the opportunity to increase spatial resolution of MRSI within reasonable scan times.}, language = {en} } @article{StaatVu2012, author = {Staat, Manfred and Vu, Duc Khoi}, title = {Limit analysis of flaws in pressurized pipes and cylindrical vessels Part II: Circumferential defects}, series = {Engineering Fracture Mechanic}, volume = {97}, journal = {Engineering Fracture Mechanic}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0013-7944}, doi = {10.1016/j.engfracmech.2012.05.017}, pages = {314 -- 333}, year = {2012}, abstract = {Upper and lower bound theorems of limit analyses have been presented in part I of the paper. Part II starts with the finite element discretization of these theorems and demonstrates how both can be combined in a primal-dual optimization problem. This recently proposed numerical method is used to guide the development of a new class of closed-form limit loads for circumferential defects, which show that only large defects contribute to plastic collapse with a rapid loss of strength with increasing crack sizes. The formulae are compared with primal-dual FEM limit analyses and with burst tests. Even closer predictions are obtained with iterative limit load solutions for the von Mises yield function and for the Tresca yield function. Pressure loading of the faces of interior cracks in thick pipes reduces the collapse load of circumferential defects more than for axial flaws. Axial defects have been treated in part I of the paper.}, language = {en} } @article{AggarwalDhimanKumaretal.2012, author = {Aggarwal, Pranav and Dhiman, Shashi K. and Kumar, G. and Scherer, Ulrich W. and Singla, M. L. and Srivastava, Alok}, title = {Optical study of poly(ethyleneterephthalate) modified by different ionizing radiation dose}, series = {Indian Journal of Pure and Applied Physics}, volume = {50}, journal = {Indian Journal of Pure and Applied Physics}, number = {2}, publisher = {Council Of Scientific And Industrial Research (CSIR), National Institute Of Science Communication and Policy Research (NIScPR)}, address = {New Delhi}, issn = {0019-5596}, pages = {129 -- 132}, year = {2012}, abstract = {Thin films of poly(ethyleneterephthalate) [PET]were exposed to radiation dose ranging from 10 to 30 kGy by using gamma rays in the range 12.8-177.8 MGy using swift light ions of hydrogen. There was no effect of the radiation dose on the optical behaviour of PET as a result of exposure to radiation dose up to 30 kGy brought about by gamma rays but a significant decrease in the optical band gap values was observed when PET was exposed to swift light ions of hydrogen. The data obtained are discussed in terms of optical studies carried out on PET using swift heavy ions.}, language = {en} } @inproceedings{KirchnerHenkelNaetheretal.2008, author = {Kirchner, Patrick and Henkel, H. and N{\"a}ther, Niko and Spelthahn, H. and Schneider, A. and Berger, J{\"o}rg and Kolstad, J. and Friedrich, P. and Sch{\"o}ning, Michael Josef}, title = {RFID-basiertes Sensorsystem zur Realisierung intelligenter Verpackungen f{\"u}r die Nahrungsmittelindustrie}, series = {KMU - innovativ: IKT 2008. CD-ROM : BMBF-Statustagung KMU - innovativ: IKT, Darmstadt, 17. - 18. Nov. 2008}, booktitle = {KMU - innovativ: IKT 2008. CD-ROM : BMBF-Statustagung KMU - innovativ: IKT, Darmstadt, 17. - 18. Nov. 2008}, number = {CD-ROM-Ausg.}, publisher = {BMBF}, address = {Berlin}, pages = {9 S.}, year = {2008}, language = {de} } @book{GalleyMinoggioSchubaetal.2016, author = {Galley, Birgit and Minoggio, Ingo and Schuba, Marko and Bischoff, Barbara and H{\"o}fken, Hans-Wilhelm}, title = {Unternehmenseigene Ermittlungen : Recht - Kriminalistik - IT}, publisher = {Erich Schmidt Verlag}, address = {Berlin}, isbn = {978-3-503-16531-5}, pages = {XIII, 372 S.}, year = {2016}, language = {de} } @article{RibitschKarlBirnerGruenbergeretal.2010, author = {Ribitsch, D. and Karl, W. and Birner-Gruenberger, R. and Gruber, K. and Eiteljoerg, I. and Remler, P. and Wieland, S. and Siegert, Petra and Maurer, Karl-Heinz and Schwab, H.}, title = {C-terminal truncation of a metagenome-derived detergent protease for effective expression in E. coli}, series = {Journal of biotechnology}, volume = {150}, journal = {Journal of biotechnology}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-4863 (E-Journal); 0168-1656 (Print)}, doi = {10.1016/j.jbiotec.2010.09.947}, pages = {408 -- 416}, year = {2010}, abstract = {Recently, a new alkaline protease named HP70 showing highest homology to extracellular serine proteases of Stenotrophomonas maltophilia and Xanthomonas campestris was found in the course of a metagenome screening for detergent proteases (Niehaus et al., submitted for publication). Attempts to efficiently express the enzyme in common expression hosts had failed. This study reports on the realization of overexpression in Escherichia coli after structural modification of HP70. Modelling of HP70 resulted in a two-domain structure, comprising the catalytic domain and a C-terminal domain which includes about 100 amino acids. On the basis of the modelled structure the enzyme was truncated by deletion of most of the C-terminal domain yielding HP70-C477. This structural modification allowed effective expression of active enzyme using E. coli BL21-Gold as the host. Specific activity of HP70-C477 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 30 ± 5 U/mg compared to 8 ± 1 U/mg of the native enzyme. HP70-C477 was most active at 40 °C and pH 7-11; these conditions are prerequisite for a potential application as detergent enzyme. Determination of kinetic parameters at 40 °C and pH = 9.5 resulted in KM = 0.23 ± 0.01 mM and kcat = 167.5 ± 3.6 s⁻¹. MS-analysis of peptide fragments obtained from incubation of HP70 and HP70-C477 with insulin B indicated that the C-terminal domain influences the cleavage preferences of the enzyme. Washing experiments confirmed the high potential of HP70-C477 as detergent protease.}, language = {en} }