TY  - GEN
A1  - Duwe, A.
A1  - Sieker, T.
A1  - Tippkötter, Nils
A1  - Ulber, Roland
T1  - Grasssilage als Substrat zur fermentativen Produktion organischer Säuren
T2  - Chemie Ingenieur Technik
N2  - Der zunehmende Bedarf an fossilen Rohstoffen bei gleichzeitig abnehmender Versorgungssicherheit führt zu einer intensiven Suche nach erneuerbaren Ressourcen. Ein vielversprechendes Ausgangsmaterial mit einer weltweiten Verfügbarkeit stellt Gras dar. In 2012 wurden in Deutschland 33 Millionen Tonnen (Heugewicht) Gras auf 4,82 Millionen Hektar Ackerland produziert, davon wurden 60,5 % siliert. Durch die Silierung kann Gras als Substrat zeitlich uneingeschränkt verfügbar sein, ohne dem Risiko des schnellen Verderbs ausgesetzt zu sein. Eine Schlüsselrolle im Rahmen des Silierprozesses nimmt die Produktion von Milchsäure ein. Milchsäure ist einbedeutendes biotechnologisches Produkt für die Lebensmittel- und die chemische Industrie. Im Rahmen dieser Arbeit wird die vollständige Umwandlung der fermentierbaren Zucker in der Silage zu Milchsäure angestrebt, um die maximale Ausbeute der organischen Säure zu erreichen. Im ersten Verfahrensschritt wird die Silage gepresst und der erhaltene Presskuchen einer Liquid-Hot-Water-Behandlung unterzogen. Durch diese einfache Vorbehandlung können hohe Glucoseausbeuten im nachfolgenden SSF-Schritt bei gleichzeitig geringem Enzymeinsatz und Chemikalienverbrauch realisiert werden. Zur Aufreinigung der Milchsäure wurden extraktive und chromatographische Methoden untersucht.
Y1  - 2014
U6  - https://doi.org/10.1002/cite.201450345
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung 2014 und 31. DECHEMA-Jahrestagung der Biotechnologen, 30. September - 2. Oktober 2014, Eurogress Aachen
VL  - 86
IS  - 9
SP  - 1400
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Guo, Yuanyuan
A1  - Miyamoto, Ko-ichiro
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Theoretical study and simulation of light-addressable potentiometric sensors
JF  - Physica status solidi (A) : applications and materials
N2  - The light-addressable potentiometric sensor (LAPS) is a semiconductor-based potentiometric sensor using a light probe with an ability of detecting the concentration of biochemical species in a spatially resolved manner. As an important biomedical sensor, research has been conducted to improve its performance, for instance, to realize high-speed measurement. In this work, the idea of facilitating the device-level simulation, instead of using an equivalent-circuit model, is presented for detailed analysis and optimization of the performance of the LAPS. Both carrier distribution and photocurrent response have been simulated to provide new insight into both amplitude-mode and phase-mode operations of the LAPS. Various device parameters can be examined to effectively design and optimize the LAPS structures and setups for enhanced performance.
Y1  - 2014
U6  - https://doi.org/10.1002/pssa.201330354
SN  - 0031-8965
VL  - 211
IS  - 6
SP  - 1467
EP  - 1472
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Handtke, Stefan
A1  - Schroeter, Rebecca
A1  - Jürgen, Britta
A1  - Methling, Karen
A1  - Schlüter, Rabea
A1  - Albrecht, Dirk
A1  - Hijum, Sacha A. F. T. van
A1  - Bongaerts, Johannes
A1  - Maurer, Karl-Heinz
A1  - Lalk, Michael
A1  - Schweder, Thomas
A1  - Hecker, Michael
A1  - Voigt, Birgit
T1  - Bacillus pumilus reveals a remarkably high resistance to hydrogen peroxide provoked oxidative stress
JF  - PLOS one
N2  - Bacillus pumilus is characterized by a higher oxidative stress resistance than other comparable industrially relevant Bacilli such as B. subtilis or B. licheniformis. In this study the response of B. pumilus to oxidative stress was investigated during a treatment with high concentrations of hydrogen peroxide at the proteome, transcriptome and metabolome level. Genes/proteins belonging to regulons, which are known to have important functions in the oxidative stress response of other organisms, were found to be upregulated, such as the Fur, Spx, SOS or CtsR regulon. Strikingly, parts of the fundamental PerR regulon responding to peroxide stress in B. subtilis are not encoded in the B. pumilus genome. Thus, B. pumilus misses the catalase KatA, the DNA-protection protein MrgA or the alkyl hydroperoxide reductase AhpCF. Data of this study suggests that the catalase KatX2 takes over the function of the missing KatA in the oxidative stress response of B. pumilus. The genome-wide expression analysis revealed an induction of bacillithiol (Cys-GlcN-malate, BSH) relevant genes. An analysis of the intracellular metabolites detected high intracellular levels of this protective metabolite, which indicates the importance of bacillithiol in the peroxide stress resistance of B. pumilus.
Y1  - 2014
U6  - https://doi.org/10.1371/journal.pone.0085625
SN  - 1932-6203
VL  - 9
IS  - 1
PB  - PLOS
CY  - San Francisco
ER  - 
TY  - JOUR
A1  - Handtke, Stefan
A1  - Volland, Sonja
A1  - Methling, Karen
A1  - Albrecht, Dirk
A1  - Becher, Dörte
A1  - Nehls, Jenny
A1  - Bongaerts, Johannes
A1  - Maurer, Karl-Heinz
A1  - Lalk, Michael
A1  - Liesegang, Heiko
A1  - Voigt, Birgit
A1  - Daniel, Rolf
A1  - Hecker, Michael
T1  - Cell physiology of the biotechnological relevant bacterium Bacillus pumilus - An omics-based approach
JF  - Journal of Biotechnology
N2  - Members of the species Bacillus pumilus get more and more in focus of the biotechnological industry as potential new production strains. Based on exoproteome analysis, B. pumilus strain Jo2, possessing a high secretion capability, was chosen for an omics-based investigation. The proteome and metabolome of B. pumilus cells growing either in minimal or complex medium was analyzed. In total, 1542 proteins were identified in growing B. pumilus cells, among them 1182 cytosolic proteins, 297 membrane and lipoproteins and 63 secreted proteins. This accounts for about 43% of the 3616 proteins encoded in the B. pumilus Jo2 genome sequence. By using GC–MS, IP-LC/MS and H NMR methods numerous metabolites were analyzed and assigned to reconstructed metabolic pathways. In the genome sequence a functional secretion system including the components of the Sec- and Tat-secretion machinery was found. Analysis of the exoproteome revealed secretion of about 70 proteins with predicted secretion signals. In addition, selected production-relevant genome features such as restriction modification systems and NRPS clusters of B. pumilus Jo2 are discussed.
Y1  - 2014
U6  - https://doi.org/10.1016/j.jbiotec.2014.08.028
SN  - 1873-4863 (E-Journal); 0168-1656 (Print)
IS  - 192(A)
SP  - 204
EP  - 214
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Heine, A.
A1  - Herrmann, G.
A1  - Selmer, Thorsten
A1  - Terwesten, F.
A1  - Buckel, W.
A1  - Reuter, K.
T1  - High resolution crystal structure of clostridium propionicum β-Alanyl-CoA:Ammonia Lyase, a new member of the "Hot Dog Fold" protein superfamily
JF  - Proteins
N2  - Clostridium propionicum is the only organism known to ferment β-alanine, a constituent of coenzyme A (CoA) and the phosphopantetheinyl prosthetic group of holo-acyl carrier protein. The first step in the fermentation is a CoA-transfer to β-alanine. Subsequently, the resulting β-alanyl-CoA is deaminated by the enzyme β-alanyl-CoA:ammonia lyase (Acl) to reversibly form ammonia and acrylyl-CoA. We have determined the crystal structure of Acl in its apo-form at a resolution of 0.97 Å as well as in complex with CoA at a resolution of 1.59 Å. The structures reveal that the enyzme belongs to a superfamily of proteins exhibiting a so called “hot dog fold” which is characterized by a five-stranded antiparallel β-sheet with a long α-helix packed against it. The functional unit of all “hot dog fold” proteins is a homodimer containing two equivalent substrate binding sites which are established by the dimer interface. In the case of Acl, three functional dimers combine to a homohexamer strongly resembling the homohexamer formed by YciA-like acyl-CoA thioesterases. Here, we propose an enzymatic mechanism based on the crystal structure of the Acl·CoA complex and molecular docking. Proteins 2014; 82:2041–2053. © 2014 Wiley Periodicals, Inc.
Y1  - 2014
U6  - https://doi.org/10.1002/prot.24557
SN  - 1097-0134 (E-Journal); 0887-3585 (Print)
VL  - 82
IS  - 9
SP  - 2041
EP  - 2053
PB  - Wiley-Liss
CY  - New York
ER  - 
TY  - JOUR
A1  - Heinze, Daniel
A1  - Mang, Thomas
A1  - Peter, Karin
A1  - Möller, Martin
A1  - Weichold, Oliver
T1  - Synthesis of low molecular weight poly(vinyl acetate) and its application as plasticizer
JF  - Journal of applied polymer science
N2  - Poly(vinyl acetate), PVAc, with a degree of polymerization Xn = 10 was prepared by chain-transfer radical polymerization using carbon tetrachloride and used as oligomeric plasticizer for commercial PVAc. However, the chlorinated chain ends cause a low thermal stability requiring mild Cl/H substitution. The product exhibits high thermal stability and excellent melt-compounding properties. Blends of oligomeric and commercial PVAc show single glass transition temperatures which decrease with higher oligomer content and exhibit small negative deviations from Fox' linear additivity rule. This indicates plasticization and miscibility being mainly due to entropic effects. Injection-moulded thick specimens show ductile behaviour at oligomer contents >10 wt %, while sheets with a thickness of 0.2–0.5 mm appear flexible already at 7.5 wt %. The oxygen permeability coefficients are an order of magnitude lower than those of low-density polyethylene. Due to the sum of their properties, the plasticized sheets present a promising alternative in the preparation of barrier materials.
Y1  - 2014
U6  - https://doi.org/10.1002/app.40226
SN  - 1097-4628 (E-Journal); 0021-8995 (Print)
VL  - 131
IS  - 9
SP  - Article No. 40226
PB  - Wiley
CY  - New York
ER  - 
TY  - JOUR
A1  - Hentschke, Reinhard
A1  - Hager, Jonathan
A1  - Hojdis, Nils
T1  - Molecular Modeling Approach to the Prediction of Mechanical Properties of Silica-Reinforced Rubbers
JF  - Journal of Applied Polymer Science
N2  - Recently, we have suggested a nanomechanical model for dissipative loss in filled elastomer networks in the context of the Payne effect. The mechanism is based on a total interfiller particle force exhibiting an intermittent loop, due to the combination of short-range repulsion and dispersion forces with a long-range elastic attraction. The sum of these forces leads, under external strain, to a spontaneous instability of “bonds” between the aggregates in a filler network and attendant energy dissipation. Here, we use molecular dynamics simulations to obtain chemically realistic forces between surface modified silica particles. The latter are combined with the above model to estimate the loss modulus and the low strain storage modulus in elastomers containing the aforementioned filler-compatibilizer systems. The model is compared to experimental dynamic moduli of silica filled rubbers. We find good agreement between the model predictions and the experiments as function of the compatibilizer's molecular structure and its bulk concentration.
KW  - theory and modeling
KW  - supramolecular structures
KW  - rubber
KW  - mechanical properties
KW  - elastomers
Y1  - 2014
U6  - https://doi.org/10.1002/app.40806
SN  - 1097-4628
VL  - 131
IS  - 18
SP  - 1
EP  - 9
PB  - Wiley
CY  - New York, NY
ER  - 
TY  - GEN
A1  - Hering, T.
A1  - Pasteur, A.
A1  - Wollny, S.
A1  - Ulber, Roland
A1  - Tippkötter, Nils
T1  - Magnetische Separation von Gold-Nanopartikeln zur Gluconsäure-Produktion durch Hochgradient-Magnetseparation im Labormaßstab
T2  - Chemie Ingenieur Technik
N2  - Bei der Verarbeitung nachwachsender Rohstoffe entsteht aus Cellulose oder Stärke u. a. das wichtige Produkt Glucose. Diese niedermolekulare Kohlenhydratquelle wird üblicherweise als Substrat für biotechnologische und chemische Synthesen verwendet. Ein wirtschaftlich interessantes Oxidationsprodukt der Glucose ist Gluconsäure, die beispielsweise als Lebensmittelzusatzstoff (E 574), in der Medizin und Metallindustrie Verwendung findet. Die Umsetzung des Monosaccharids zu Gluconsäure erfolgt entweder durch mikrobielle Fermentation oder der Oxidation an heterogenen Katalysatoren. Die Zielsetzung der Studie ist die Untersuchung der Glucoseoxidation an magnetisierbaren Gold-Nanopartikeln unter nachfolgender Bypass-Separation des Katalysators mittels einer neuen Mini-HGMS-Einheit (Hochgradient-Magnetseparation). Dieser Filtertyp ermöglicht die selektive Trennung magnetischer Partikel aus Suspensionen mit hohem Feststoffgehalt oder Viskosität. Erste Ergebnisse zeigen eine Beladungskapazität des selbstkonstruierten Mini-HGMS von 550 mg goldbeschichteter magnetisierbarer Nanopartikel. Die Oxidation erfolgt bei einem pH-Wertvon 9, bei 40 °C und mit 100 mM Glucose in einem begasten Rührkesselreaktor. Das System soll zukünftig zum Katalysatorrecycling von hochviskosen und Feststoffbelasteten Produktströmen aus Bioraffinerien eingesetzt werden.
Y1  - 2014
U6  - https://doi.org/10.1002/cite.201450265
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung 2014 und 31. DECHEMA-Jahrestagung der Biotechnologen, 30. September - 2. Oktober 2014, Eurogress Aachen
VL  - 86
IS  - 9
SP  - 1501
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Hering, T.
A1  - Ulber, Roland
A1  - Tippkötter, Nils
T1  - Aktiver und passiver antimikrobieller Oberflächenschutz durch funktionalisierte Mikropartikel
T2  - Chemie Ingenieur Technik
N2  - Mikrobielle Verunreinigungen von Oberflächen in technischen und medizinischen Systemen sind allgegenwärtig. Sie basieren üblicherweise auf adsorptiven Oberflächenbindungen organischer Komponenten (Proteine und Fette) oder Membrankomponenten aerogener sowie wassergebundener Mikroorganismen. In laufenden Forschungsarbeiten wird eine aktive sowie passive Biomodifikation von Oberflächen zu deren Schutz vor Adsorption von Proteinen und Mikroorganismen verfolgt. Der antimikrobielle Schutz soll dabei sowohl durch die Mikrostrukturierung bzw. Rauheitsanpassung der Oberflächen durch deren Beschichtung mit Mikro-und Nanopartikeln erfolgen. Ferner werden antimikrobielle Enzyme und funktionelle Gruppen auf den Mikropartikeln gebunden, um den Oberflächenschutz zu verstärken. In ersten Versuchen wurden quartäre Ammoniumverbindungen auf eigens synthetisierten superparamagnetischen Eisenoxid-Nanopartikeln (Durchmesser 10 – 30 nm) immobilisiert und die wachstumshemmende Wirkung untersucht. Erste Ergebnisse zeigten, dass eine Konzentration von 10 mg mL⁻¹ der Ammoniumverbindung in einer Wachstumshemmung des verwendeten Gram-negativen Modell-Mikroorganismus E. coli GFPmut2 resultiert. Zurzeit werden synergistisch wirkende Kombinationen von Partikeln mit Proteasen, quartären Ammoniumverbindungen, hydrophoben Oberflächen und mikrostrukturierten Oberflächen als antimikrobieller Schutz untersucht.
Y1  - 2014
U6  - https://doi.org/10.1002/cite.201450264
SN  - 0009-286X
SN  - 1522-2640 (eISSN)
N1  - ProcessNet-Jahrestagung 2014 und 31. DECHEMA-Jahrestagung der Biotechnologen, 30. September - 2. Oktober 2014, Eurogress Aachen
VL  - 9
IS  - 86
SP  - 1474
EP  - 1475
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Hoehr, Cornelia
A1  - Paulßen, Elisabeth
A1  - Benard, Francois
A1  - Lee, Chris Jaeil
A1  - Hou, Xinchi
A1  - Badesso, Brian
A1  - Ferguson, Simon
A1  - Miao, Qing
A1  - Yang, Hua
A1  - Buckley, Ken
A1  - Hanemaayer, Victoire
A1  - Zeisler, Stefan
A1  - Ruth, Thomas
A1  - Celler, Anna
A1  - Schaffer, Paul
T1  - ⁴⁴ᶢSc production using a water target on a 13 MeV cyclotron
JF  - Nuclear medicine and biology
N2  - Access to promising radiometals as isotopes for novel molecular imaging agents requires that they are routinely available and inexpensive to obtain. Proximity to a cyclotron center outfitted with solid target hardware, or to an isotope generator for the metal of interest is necessary, both of which can introduce significant hurdles in development of less common isotopes. Herein, we describe the production of ⁴⁴Sc (t₁⸝₂ = 3.97 h, Eavg,β⁺ = 1.47 MeV, branching ratio = 94.27%) in a solution target and an automated loading system which allows a quick turn-around between different radiometallic isotopes and therefore greatly improves their availability for tracer development. Experimental yields are compared to theoretical calculations.
Y1  - 2014
U6  - https://doi.org/10.1016/j.nucmedbio.2013.12.016
SN  - 1872-9614
VL  - 41
IS  - 5
SP  - 401
EP  - 406
PB  - Elsevier
CY  - Amsterdam
ER  -