TY - JOUR A1 - Tippkötter, Nils A1 - Roikaew, W. A1 - Ulber, Roland T1 - Nitrate removal from whey concentrate with biotechnological regeneration of the waste water JF - European dairy magazine : EDM Y1 - 2008 SN - 0936-6318 IS - 1 SP - 30 EP - 32 ER - TY - JOUR A1 - Unden, G. A1 - Becker, S. A1 - Bongaerts, Johannes A1 - Holighaus, G. A1 - Schirawski, J. A1 - Six, S. T1 - O2-sensing and O2-dependent gene regulation in facultatively anaerobic bacteria JF - Archives of microbiology Y1 - 1995 SN - 1432-072X (E-Journal); 0003-9276 (Print); 0302-8933 (Print) VL - Vol. 164 IS - Iss. 2 SP - 81 EP - 90 ER - TY - CHAP A1 - Tippkötter, Nils A1 - Stückmann, H. A1 - Winkelmann, G. A1 - Noack, U. A1 - Beutel, S. A1 - Scheper, T. A1 - Ulber, Roland T1 - Optimisation of antibody-labelling of gold colloids for their application in an immunchromatographic assay for microcystin-LR T2 - European BioPerspectives : celebrating the 25th DECHEMA annual convention of biotechnologists ; 30 May - 1 June 2007, Cologne, Germany ; book of abstracts ; abstracts, poster programme Y1 - 2007 SP - 126 PB - Dechema CY - Frankfurt am Main ER - TY - PAT A1 - Al-Kaidy, Huschyar A1 - Tippkötter, Nils A1 - Ulber, Roland T1 - Vorrichtung und Verfahren zur Bestimmung des Kontaktwinkels eines Flüssigkörpers mit einer Festkörperoberfläche N2 - Die vorliegende Erfindung betrifft eine Vorrichtung und ein Verfahren zur Bestimmung des Kontaktwinkels eines flüssigen oder mit Flüssigkeit gefüllten Körpers. Dieser besteht aus einem Träger (1) und einer damit verbundenen, in einem Winkelbereich von mehr als 0 ° bis maximal 90 ° neigbaren Ebene (8) mit einer darin ausgebildeten Abrollbahn (9) für den flüssigen oder mit Flüssigkeit gefüllten Körper. An der Ebene (8) sind mehrere Sensoren (11,12) zur Erfassung der Rolldauer des Körpers entlang der Rollstrecke angeordnet. Erfindungsgemäß ist vorgesehen, dass die Einstellung des Neigungswinkels der Ebene (8) über ein Winkelmessgerät (10) erfolgt, wodurch ein Abrollwinkel erfassbar ist, bei dem der Körper in Bewegung gerät. Aus der Rolldauer, der Rollstrecke und dem Abrollwinkel wird der Kontaktwinkel des Körpers ermittelt. Y1 - 2016 N1 - Patent auch unter DE102014000419 und WO2015107159 veröffentlicht. ER - TY - JOUR A1 - Tippkötter, Nils A1 - Deterding, A. A1 - Ulber, Roland T1 - Determination of acetic acid in fermentation broth by gas-diffusion technique JF - Engineering in Life Sciences N2 - Due to the interfering effects of acetic acid in many fermentation processes, a gas-diffusion technique was developed for the online determination of acetic acid. The measurements were accomplished with a flow diffusion analysis (FDA) unit from the TRACE Analytics GmbH, Braunschweig, Germany. The diffusion analysis is based on the UV-absorbance of acetic acid at 205 nm. The measurement was achieved by the separation of an acceptor and a carrier stream (acidified fermentation broth) using a gas permeable polytetrafluoroethylene (PTFE) membrane, whereby broth constituents that would otherwise disturb the UV-measurement of acetic acid, are held back efficiently. Merely, the fermentation by-products, e.g. formic acid, is capable of diffusing through the membrane. While formic acid can disturb the measurement, carbon dioxide does not absorb at 205 nm. The method operates with time-dependent sample enrichment. During the analysis, a small volume of the acceptor stream is stopped for a defined time interval in the acceptor chamber. During this period, the gaseous acetic acid diffuses through the membrane and is enriched in the acceptor chamber. Subsequently after the enrichment, the acceptor stream flows through a UV-detector. The intensity of the signal is proportional to the acetic acid concentration. Online measurements in bioreactors via a sterile filtration probe have been accomplished. A linear calibration in the range of 0.5–5.0 g/L acetic acid with a relative standard deviation of <5 % was obtained. A sampling rate of 8 samples per hour was possible. The system was applied for the determination of acetic acid in E. coli fermentation broth. The instrument is easy to clean, very user-friendly and does not require any toxic or expensive reagents. Y1 - 2008 U6 - https://doi.org/10.1002/elsc.200820227 VL - 8 IS - 1, Special Issue: Technical Systems for the Use in Life Sciences SP - 62 EP - 67 ER - TY - JOUR A1 - Bäcker, Matthias A1 - Rakowski, D. A1 - Poghossian, Arshak A1 - Biselli, Manfred A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Chip-based amperometric enzyme sensor system for monitoring of bioprocesses by flow-injection analysis JF - Journal of Biotechnology N2 - A microfluidic chip integrating amperometric enzyme sensors for the detection of glucose, glutamate and glutamine in cell-culture fermentation processes has been developed. The enzymes glucose oxidase, glutamate oxidase and glutaminase were immobilized by means of cross-linking with glutaraldehyde on platinum thin-film electrodes integrated within a microfluidic channel. The biosensor chip was coupled to a flow-injection analysis system for electrochemical characterization of the sensors. The sensors have been characterized in terms of sensitivity, linear working range and detection limit. The sensitivity evaluated from the respective peak areas was 1.47, 3.68 and 0.28 μAs/mM for the glucose, glutamate and glutamine sensor, respectively. The calibration curves were linear up to a concentration of 20 mM glucose and glutamine and up to 10 mM for glutamate. The lower detection limit amounted to be 0.05 mM for the glucose and glutamate sensor, respectively, and 0.1 mM for the glutamine sensor. Experiments in cell-culture medium have demonstrated a good correlation between the glutamate, glutamine and glucose concentrations measured with the chip-based biosensors in a differential-mode and the commercially available instrumentation. The obtained results demonstrate the feasibility of the realized microfluidic biosensor chip for monitoring of bioprocesses. Y1 - 2013 U6 - https://doi.org/10.1016/j.jbiotec.2012.03.014 SN - 0168-1656 VL - 163 IS - 4 SP - 371 EP - 376 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Tran, Quang Hon A1 - Bongaerts, Johannes A1 - Vlad, Dorina A1 - Unden, Gottfried T1 - Requirement for the proton-pumping NADH dehydrogenase I of Escherichia coli in respiration of NADH to fumarate and its bioenergetic implications JF - European journal of biochemistry Y1 - 1997 SN - 0014-2956 VL - Vol. 244 IS - Iss. 1 SP - 155 EP - 160 ER - TY - JOUR A1 - Wiegand, Sandra A1 - Voigt, Birgit A1 - Albrecht, Dirk A1 - Bongaerts, Johannes A1 - Evers, Stefan A1 - Hecker, Michael A1 - Daniel, Rolf A1 - Liesegang, Heiko T1 - Fermentation stage-dependent adaptations of Bacillus licheniformis during enzyme production JF - Microbial Cell Factories Y1 - 2013 U6 - https://doi.org/10.1186/1475-2859-12-120 SN - 1475-2859 VL - 12 SP - 120 PB - Biomed Central CY - London ER - TY - CHAP A1 - Tippkötter, Nils A1 - Roikaew, W. A1 - Ulber, Roland T1 - An automated pilot plant for the bioengineering processing of concentrated whey T2 - European BioPerspectives : in cooperation with BIOTECHNICA 2008 : 7 - 9 October 2008 Hannover, Germany ; book of abstracts ; abstracts, poster programme Y1 - 2008 SP - 98 PB - Dechema CY - Frankfurt am Main ER - TY - JOUR A1 - Zientz, Evelyn A1 - Bongaerts, Johannes A1 - Unden, Gottfried T1 - Fumarate regulation of gene expression in Escherichia coli by the DcuSR (dcuSR genes) two-component regulatory system JF - Journal of bacteriology Y1 - 1998 SN - 1098-5530 (E-Journal); 0021-9193 (Print) VL - Vol. 180 IS - No. 20 SP - 5421 EP - 5425 ER -