TY  - JOUR
A1  - Falkenberg, Fabian
A1  - Bott, Michael
A1  - Bongaerts, Johannes
A1  - Siegert, Petra
T1  - Phylogenetic survey of the subtilase family and a data-mining-based search for new subtilisins from Bacillaceae
JF  - Frontiers in Microbiology
N2  - The subtilase family (S8), a member of the clan SB of serine proteases are ubiquitous in all kingdoms of life and fulfil different physiological functions. Subtilases are divided in several groups and especially subtilisins are of interest as they are used in various industrial sectors. Therefore, we searched for new subtilisin sequences of the family Bacillaceae using a data mining approach. The obtained 1,400 sequences were phylogenetically classified in the context of the subtilase family. This required an updated comprehensive overview of the different groups within this family. To fill this gap, we conducted a phylogenetic survey of the S8 family with characterised holotypes derived from the MEROPS database. The analysis revealed the presence of eight previously uncharacterised groups and 13 subgroups within the S8 family. The sequences that emerged from the data mining with the set filter parameters were mainly assigned to the subtilisin subgroups of true subtilisins, high-alkaline subtilisins, and phylogenetically intermediate subtilisins and represent an excellent source for new subtilisin candidates.
Y1  - 2022
U6  - https://doi.org/10.3389/fmicb.2022.1017978
SN  - 1664-302X
VL  - 2022
IS  - 13
PB  - Frontiers
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Everaers, Ralf
A1  - Karimi-Varzaneh, Hossein Ali
A1  - Fleck, Franz
A1  - Hojdis, Nils
A1  - Svaneborg, Carsten
T1  - Kremer–Grest Models for Commodity Polymer Melts: Linking Theory, Experiment, and Simulation at the Kuhn Scale
JF  - Macromolecules
N2  - The Kremer–Grest (KG) polymer model is a standard model for studying generic polymer properties in molecular dynamics simulations. It owes its popularity to its simplicity and computational efficiency, rather than its ability to represent specific polymers species and conditions. Here we show that by tuning the chain stiffness it is possible to adapt the KG model to model melts of real polymers. In particular, we provide mapping relations from KG to SI units for a wide range of commodity polymers. The connection between the experimental and the KG melts is made at the Kuhn scale, i.e., at the crossover from the chemistry-specific small scale to the universal large scale behavior. We expect Kuhn scale-mapped KG models to faithfully represent universal properties dominated by the large scale conformational statistics and dynamics of flexible polymers. In particular, we observe very good agreement between entanglement moduli of our KG models and the experimental moduli of the target polymers.
Y1  - 2020
U6  - https://doi.org/10.1021/acs.macromol.9b02428
SN  - 1520-5835
VL  - 53
IS  - 6
SP  - 1901
EP  - 1916
PB  - ACS Publications
CY  - Washington, DC
ER  - 
TY  - CHAP
A1  - Engel, Mareike
A1  - Thieringer, Julia
A1  - Tippkötter, Nils
T1  - Linking bioprocess engineering and electrochemistry for sustainable biofuel production
T2  - Young Researchers Symposium, YRS 2016. Proceedings
N2  - Electromicrobial engineering is an emerging, highly interdisciplinary research area linking bioprocesses with electrochemistry. In this work, microbial electrosynthesis (MES) of biobutanol is carried out during acetone-butanol-ethanol (ABE) fermentations with Clostridium acetobutylicum. A constant electric potential of −600mV (vs. Ag/AgCl) with simultaneous addition of the soluble redox mediator neutral red is used in order to study the electron transfer between the working electrode and the bacterial cells. The results show an earlier initiation of solvent production for all fermentations with applied potential compared to the conventional ABE fermentation. The f inal butanol concentration can be more than doubled by the application of a negative potential combined with addition of neutral red. Moreover a higher biofilm formation on the working electrode compared to control cultivations has been observed. In contrast to previous studies, our results also indicate that direct electron transfer (DET) might be possible with C. acetobutylicum. The presented results make microbial butanol production economically attractive and therefore support the development of sustainable production processes in the chemical industry aspired by the “Centre for resource-efficient chemistry and raw material change” as well as the the project “NanoKat” working on nanostructured catalysts in Kaiserslautern.
Y1  - 2016
N1  - Young Researchers Symposium, YRS 2016, 14th - 15th April 2016, Fraunhofer-Zentrum Kaiserslautern
SP  - 49
EP  - 53
PB  - Fraunhofer Verlag
CY  - Karlsruhe
ER  - 
TY  - JOUR
A1  - Engel, Mareike
A1  - Holtmann, Dirk
A1  - Ulber, Roland
A1  - Tippkötter, Nils
T1  - Increased Biobutanol Production by Mediator‐Less Electro‐Fermentation
JF  - Biotechnology Journal
N2  - A future bio-economy should not only be based on renewable raw materials but also in the raise of carbon yields of existing production routes. Microbial electrochemical technologies are gaining increased attention for this purpose. In this study, the electro-fermentative production of biobutanol with C. acetobutylicum without the use of exogenous mediators is investigated regarding the medium composition and the reactor design. It is shown that the use of an optimized synthetic culture medium allows higher product concentrations, increased biofilm formation, and higher conductivities compared to a synthetic medium supplemented with yeast extract. Moreover, the optimization of the reactor system results in a doubling of the maximum product concentrations for fermentation products. When a working electrode is polarized at −600 mV vs. Ag/AgCl, a shift from butyrate to acetone and butanol production is induced. This leads to an increased final solvent yield of Yᴀᴃᴇ = 0.202 gg⁻¹ (control 0.103 gg⁻¹), which is also reflected in a higher carbon efficiency of 37.6% compared to 23.3% (control) as well as a fourfold decrease in simplified E-factor to 0.43. The results are promising for further development of biobutanol production in bioelectrochemical systems in order to fulfil the principles of Green Chemistry.
Y1  - 2018
U6  - https://doi.org/10.1002/biot.201800514
SN  - 1860-7314
VL  - 14
IS  - 4
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Engel, Mareike
A1  - Gemünde, Andre
A1  - Holtmann, Dirk
A1  - Müller-Renno, Christine
A1  - Ziegler, Christiane
A1  - Tippkötter, Nils
A1  - Ulber, Roland
T1  - Clostridium acetobutylicum’s connecting world: cell appendage formation in bioelectrochemical systems
JF  - ChemElectroChem
N2  - Bacterial cell appendix formation supports cell-cell interaction, cell adhesion and cell movement. Additionally, in bioelectrochemical systems (BES), cell appendages have been shown to participate in extracellular electron transfer. In this work, the cell appendix formation of Clostridium acetobutylicum in biofilms of a BES are imaged and compared with conventional biofilms. Under all observed conditions, the cells possess filamentous appendages with a higher number and density in the BES. Differences in the amount of extracellular polymeric substance in the biofilms of the electrodes lead to the conclusion that the cathode can be used as electron donor and the anode as electron acceptor by C. acetobutylicum. When using conductive atomic force microscopy, a current response of about 15 nA is found for the cell appendages from the BES. This is the first report of conductivity for clostridial cell appendices and represents the basis for further studies on their role for biofilm formation and electron transfer.
Y1  - 2019
U6  - https://doi.org/10.1002/celc.201901656
SN  - 2196-0216
VL  - 7
IS  - 2
SP  - 414
EP  - 420
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Engel, Mareike
A1  - Bayer, Hendrik
A1  - Holtmann, Dirk
A1  - Tippkötter, Nils
A1  - Ulber, Roland
T1  - Flavin secretion of Clostridium acetobutylicum in a bioelectrochemical system - Is an iron limitation involved?
JF  - Bioelectrochemistry
Y1  - 2019
U6  - https://doi.org/10.1016/j.bioelechem.2019.05.014
SN  - 1567-5394
IS  - In Press, Accepted Manuscript
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - GEN
A1  - Engel, M.
A1  - Tippkötter, Nils
T1  - Einfluss eines Phenazin-Mediators und elektrischen Potenzials auf die Aceton-Butanol-Ethanol-Fermentation
T2  - Chemie Ingenieur Technik
N2  - In den letzten Jahren haben nachhaltige, biotechnologische Prozesse zunehmend an Bedeutung gewonnen. Die Aceton-Butanol-Ethanol-Fermentation (ABE-Fermentation) mit dem anaeroben Bakterium Clostridium acetobutylicum zur Gewinnung von Biobutanol könnte in diesem Zusammenhang eine Möglichkeit der nachhaltigen Kraftstoffproduktion darstellen. In dieser Arbeit wird der Einfluss zusätzlich verfügbarer Elektronen durch den Einsatz des Phenazin-Farbstoffs Neutralrot als Redoxmediator sowie das Anlegen eines elektrischen Potenzials während der ABE-Fermentation untersucht. Es wird gezeigt, dass das Neutralrot keinen Einfluss auf die Leerlaufspannung von ca. 500 mV vs. Ag/AgCl während der Fermentation hat. Der Mediator bewirkt allerdings eine frühere Butanolbildung sowie höhere Butanolkonzentrationen. Wird zudem die Mediatorkonzentration von 125 mM auf 250 mM angehoben, wird dabei auch die maximale Butanolkonzentration um 36 % ± 1,8 % innerhalb von28 Stunden gesteigert.
Y1  - 2016
U6  - https://doi.org/10.1002/cite.201650105
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung 2016 und 32. DECHEMA-Jahrestagung der Biotechnologen 2016, 12. - 15. September 2016, Eurogress Aachen
VL  - 88
IS  - 9
SP  - 1254
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - CHAP
A1  - Engel, M.
A1  - Thieringer, J.
A1  - Tippkötter, Nils
T1  - Microbial electrosynthesis for sustainable biobutanol production
T2  - New frontiers of biotech-processes (Himmelfahrtstagung) : 02-04 May 2016, Rhein-Mosel-Halle, Koblenz/Germany
Y1  - 2016
SP  - 77
EP  - 78
PB  - DECHEMA
CY  - Frankfurt am Main
ER  - 
TY  - GEN
A1  - Engel, M.
A1  - Bayer, H.
A1  - Ulber, Roland
A1  - Tippkötter, Nils
T1  - Kommt es in Elektrofermentationen mit Clostridium acetobutylicum zu einer Eisenlimitierung?
T2  - Chemie Ingenieur Technik
N2  - Das strikt anaerobe Bakterium Clostridium acetobutylicum bildet die Lösemittel Aceton, Butanol und Ethanol (ABE-Fermentation). Im Fall einer Eisenlimitierung kommt es zusätzlich zu einer Riboflavinsekretion (RF), was durch die gelbe Färbung des Kulturüberstands erkennbar ist. In dieser Arbeit wurde beobachtet, dass während Elektrofermentationen mit C. acetobutylicum bei –600 mV eine gelbe Färbung auftritt. Es wurde deshalb untersucht, ob eine Eisenlimitierung im bio-elektrochemischen System (BES) vorliegt. Hierzu wurden die Flavinspezien bei Kultivierungen in Medien mit einer Eisenlimitierung bzw. mit ausreichend Eisen in Serumflaschen sowie im BES mit und ohne angelegtem Potenzial verglichen. In den Serumflaschenversuchen wurden RF und Flavinadenindinukleotid (FAD)-Konzentrationen von ‡ 20 mg L⁻¹ sowie Flavinmononukleotid (FMN)-Konzentrationen von ca. 5 mg L⁻¹ detektiert. Bei ausreichender Eisenverfügbarkeit hingegen wurden in den Serumflaschen fast keine Flavine sekretiert. Im BES bei –600 mV hingegen wurde auch in diesen Kulturüberständen FMN und FAD (1–5 mg L⁻¹ ),jedoch kein RF gemessen. Diese Ergebnisse zeigen, dass die Flavinbildung im BES mit angelegtem Potenzial nicht mit der Flavinbildung unter Eisenlimitierung in Serumflaschen korreliert. Andere Faktoren für eine mögliche Flavinbildung werden aktuell näher betrachtet.
Y1  - 2018
U6  - https://doi.org/10.1002/cite.201855047
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung und 33. DECHEMA-Jahrestagung der Biotechnologen 2018, 10. - 13. September 2018, Eurogress Aachen
VL  - 90
IS  - 9
SP  - 1154
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Zang, Thorsten
A1  - Buck, Manfred
T1  - Ruß-Immissionsmessungen im Einflußbereich des Kraftfahrzeugverkehrs
JF  - Staub, Reinhaltung der Luft : air quality control. 50 (1990)
Y1  - 1990
SN  - 0039-0771
SP  - 93
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Thomzik, Manfred
T1  - Das Entstehen geruchsintensiver schwefelhaltiger organischer Verbindungen in Lackierereien und Möglichkeiten zu deren Vermeidung
JF  - Aus der Tätigkeit der LIS / Landesanstalt für Immissionsschutz des Landes Nordrhein-Westfalen. 1989 (1990)
Y1  - 1990
SN  - 0931-5497
SP  - 35
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Richter, J.
T1  - Messung kraftfahrzeugbedingter Rußimmissionen
JF  - Staub, Reinhaltung der Luft : air quality control. 54 (1994)
Y1  - 1994
SN  - 0039-0771
SP  - 19
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Remme, S.
A1  - Lehmann, G.
T1  - EPR of Cr3+ in Tris(acetylacetonato)gallium(III) Single Crystals
JF  - Inorganic Chemistry. 25 (1986)
Y1  - 1986
SN  - 0020-1669
SP  - 896
EP  - 897
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Remme, S.
A1  - Lehmann, G.
T1  - EPR and Optical Absorption of Cr3+ in CsCl and CsBr
JF  - Physica Status Solidi (B). 142 (1987), H. 2
Y1  - 1987
SN  - 0031-8957
SP  - 367
EP  - 377
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Pfeffer, Hans-Ulrich
A1  - Friesel, Jürgen
A1  - Beier, Reinhold
T1  - Air Pollution Monitoring in Street Canyons / Hans-Ulrich Pfeffer, Jürgen Friesel, Gereon Elbers, Reinhold Beier,
JF  - Transport and air pollution : proceedings ; 3rd international symposium, Palais des Papes, Avignon, France, 6 - 10 June 1994 = Transports et pollution de l'air / [Third International Symposium on Transport and Air Pollution]. Ed. by Robert Joumard. Organizer: French National Institute for Transport and Safety Research
Y1  - 1995
N1  - International Symposium on Transport and Air Pollution  <3, 1994, Avignon>
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Pfeffer, H.-U.
A1  - Friesel, J.
A1  - Beier, R.
T1  - Pilotuntersuchungen gemäß dem Verordnungsentwurf nach § 40, Abs. 2 des Bundesimmissionsschutzgesetzes / H.-U. Pfeffer, J. Friesel, G. Elbers, R. Beier, K. Ellermann
JF  - Drei Jahrzehnte Luftqualitätsüberwachung : Vorträge und Berichte zum Kolloquium "Drei Jahrzehnte Luftqualitätsüberwachung - Bilanz und Perspektiven" am 11. November 1993 in Essen / [Hrsg.: Landesanstalt für Immissionsschutz Nordrhein-Westfalen. Red. Bearb.: Robert Niesenhaus]
Y1  - 1993
N1  - LIS-Berichte ; 110 ;
SP  - 117
CY  - Essen
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Nieren, Monika
A1  - Hoffmann, Katharina
A1  - Gäb, Martina
T1  - Schnellerfassung der Wirkung von Luftschadstoffen auf Pflanzen mit der Nahinfrarotspektroskopie (NIRS). Untersuchung Ammoniak exponierter Gräser und Kräuter  / Nieren, Monika ; Hoffmann, Katharina ; Gäb, Martina ; Ooyen, Sven van ; Köllner, Barbara ; Elbe
JF  - Immissionsschutz. 13 (2008), H. 2
Y1  - 2008
SN  - 1430-9262
SP  - 82
EP  - 90
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Muratyan, Simone
T1  - Problematik verkehrsbezogener Außenluftmessungen von Partikeln (Dieselruß)
JF  - + Krebserzeugende Stoffe in der Umwelt : Herkunft, Messung, Risiko, Minimierung ; Kolloquium Mannheim, 23. bis 25. April 1991 / Kommission Reinhaltung der Luft im VDI und DIN
Y1  - 1991
SN  - 3-18-090888-2
N1  - VDI-Berichte ; 888
SP  - 143
PB  - VDI-Verl.
CY  - Düsseldorf
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Lehmann, G.
T1  - Electron paramagnetic resonance of Vanadyl ion impurities in crystalline solids: A comment
JF  - Journal of Physics and Chemistry of Solids. 46 (1985), H. 6
Y1  - 1985
SN  - 0022-3697
SP  - 761
ER  - 
TY  - JOUR
A1  - Elbers, Gereon
A1  - Lehmann, G.
T1  - Electron Paramagnetic Resonance and Optical Absorption Spectra of VO2+ in CsCl Single Crystals
JF  - Zeitschrift für Naturforschung / Section A, a journal of physical sciences. 40 (1985)
Y1  - 1985
SN  - 0932-0784
SP  - 511
ER  -