@misc{SiekerTippkoetterUlber2010, author = {Sieker, T. and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Simultane Vorbehandlung, Hydrolyse und Fermentation bei der Nutzung von gr{\"u}ner Biomasse zur Produktion von Bioethanol}, series = {Chemie Ingenieur Technik}, volume = {82}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201050319}, pages = {1601}, year = {2010}, abstract = {Gr{\"a}ser sind in der Lage, einen großen Teil der f{\"u}r eine biobasierte Wirtschaft ben{\"o}tigten Biomasse zur Verf{\"u}gung zu stellen. Wie bei anderen lignocellulosehaltigen nachwachsenden Rohstoffen erfordert die Verwertung der im Gras enthaltenen Polysaccharide einen mehrstufigen Prozess aus Vorbehandlung, Hydrolyse und Fermentation. In Gr{\"a}sern ist die Hemicellulose mitP henolcarbons{\"a}uren wie Ferula- und p-Coumars{\"a}ure verestert, die die enzymatische Hydrolyse der Cellulose und Hemicellulose ebenso effektiv behindern wie Lignin. Anders als bei holzigen Rohstoffen erm{\"o}glicht dieser Aufbau aber eine enzymatische Vorbehandlung, mit der die Phenolcarbons{\"a}uren abgespalten werden k{\"o}nnen. Da die bei der Vorbehandlung eingesetzten Enzyme in ihrer nat{\"u}rlichen Funktion synergistisch mit cellulytischen Enzymen zusammenarbeiten, besitzen sie {\"a}hnliche Optima wie die f{\"u}r die Hydrolyse der Polysaccharide eingesetzten Cellulasen und Hemicellulasen. Diese Eigenschaft erm{\"o}glicht die Integration von Vorbehandlung und Hydrolyse in einem einzigen Verfahrensschritt. Durch die Einf{\"u}hrung der enzymatischen Vorbehandlung konnte das in der Literatur bekannte SSF-Verfahren f{\"u}r die Herstellung von Ethanol aus Gr{\"a}sern um die Vorbehandlungsstufe erweitert werden. Das so realisierte simultaneous pretreatment, saccharification and fermentation (SPSF)-Verfahren stellt eine vollst{\"a}ndige Integration der drei f{\"u}r die Nutzung von Lignocellulose n{\"o}tigen Verfahrensschritte in der gr{\"u}nen Bioraffinerie dar.}, language = {de} } @article{AlKaidyDuweHusteretal.2014, author = {Al-Kaidy, Huschyar and Duwe, Anna and Huster, Manuel and Muffler, Kai and Schlegel, Christin and Sieker, Tim and Stadtm{\"u}ller, Ralf and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Biotechnologie und Bioverfahrenstechnik - Vom ersten Ullmanns Artikel bis hin zu aktuellen Forschungsthemen}, series = {Chemie Ingenieur Technik}, volume = {86}, journal = {Chemie Ingenieur Technik}, number = {12}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201400083}, pages = {2215 -- 2225}, year = {2014}, abstract = {Biotechnologie und die mit ihr verbundenen technischen Prozesse pr{\"a}gen seit Jahrtausenden die Entwicklung der Menschheit. Ausgehend von empirischen Verfahren, insbesondere zur Herstellung von Lebensmitteln und t{\"a}glichen Gebrauchsg{\"u}tern, haben sich diese Disziplinen zu einem der innovativsten Zukunftsfelder entwickelt. Durch das immer detailliertere Verst{\"a}ndnis zellul{\"a}rer Vorg{\"a}nge k{\"o}nnen mittlerweile Produktionsst{\"a}mme gezielt optimiert werden. Im Zusammenspiel mit moderner Prozesstechnik k{\"o}nnen so eine Vielzahl von Bulk- und Feinchemikalien sowie Pharmazeutika effizient hergestellt werden. In diesem Artikel werden exemplarisch einige der aktuellen Trends vorgestellt.}, language = {de} } @article{UndenBeckerBongaertsetal.1994, author = {Unden, G. and Becker, S. and Bongaerts, Johannes and Schirawski, J. and Six, S.}, title = {Oxygen regulated gene expression in facultatively anaerobic bacteria}, series = {Antonie van Leeuwenhoek}, volume = {Vol. 66}, journal = {Antonie van Leeuwenhoek}, number = {Iss. 1-3}, issn = {0003-6072 (Print) ; 1572-9699 (online)}, pages = {3 -- 22}, year = {1994}, language = {en} } @article{PasteurTippkoetterKampeisetal.2014, author = {Pasteur, Aline and Tippk{\"o}tter, Nils and Kampeis, Percy and Ulber, Roland}, title = {Optimization of high gradient magnetic separation filter units for the purification of fermentation products}, series = {IEEE TRANSACTIONS ON MAGNETICS}, volume = {50}, journal = {IEEE TRANSACTIONS ON MAGNETICS}, number = {10}, publisher = {IEEE}, address = {New York, NY}, issn = {0018-9464}, doi = {10.1109/TMAG.2014.2325535}, pages = {Artikel 5000607}, year = {2014}, abstract = {High gradient magnetic separation (HGMS) has been established since the early 1970s. A more recent application of these systems is the use in bioprocesses. To integrate the HGMS in a fermentation process, it is necessary to optimize the separation matrix with regard to the magnetic separation characteristics and permeability of the non-magnetizable components of the fermentation broth. As part of the work presented here, a combined fluidic and magnetic force finite element model simulation was created using the software COMSOL Multiphysics and compared with separation experiments. Finally, as optimal lattice orientation of the separation matrix, a transversal rhombohedral arrangement was defined. The high suitability of the new filter matrix has been verified by separation experiments.}, language = {en} } @article{UlberTippkoetter2009, author = {Ulber, Roland and Tippk{\"o}tter, Nils}, title = {Nitratfreie Molke}, series = {Rundschau f{\"u}r Fleischhygiene und Lebensmittel{\"u}berwachung}, journal = {Rundschau f{\"u}r Fleischhygiene und Lebensmittel{\"u}berwachung}, number = {4}, pages = {150 -- 152}, year = {2009}, language = {de} } @misc{AlKaidyTippkoetterUlber2013, author = {Al-Kaidy, Huschyar and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {A system and a method for the implementation of chemical, biological or physical reactions [Europ{\"a}ische Patentanmeldung]}, publisher = {Europ{\"a}isches Patentamt}, address = {Den Hague}, pages = {16 Seiten}, year = {2013}, abstract = {The invention relates to a system for the implementation of chemical, biological or physical reactions, consisting of - one or more magnetic micro-reactors, each comprising a shell made of hydrophobic magnetic nanoparticles encapsulating an aqueous core, - a plane platform comprising a surface to receive the micro-reactors, - a source that generates a magnetic field above or underneath the platform for manipulating the one or more hydrophobic magnetic micro-reactors, or for moving them along the surface of the platform from one position to another position, characterized in that the aqueous core of the one or more magnetic micro-reactors contains a reaction solution or buffer, and wherein the magnetic field generated by the source correlates to a defined position on the surface of the platform.}, language = {en} } @article{WiesenTippkoetterMuffleretal.2015, author = {Wiesen, Sebastian and Tippk{\"o}tter, Nils and Muffler, Kai and Suck, Kirstin and Sohling, Ulrich and Ruf, Friedrich and Ulber, Roland}, title = {Adsorption of fatty acids to layered double hydroxides in aqueous systems}, series = {Adsorption}, volume = {21}, journal = {Adsorption}, number = {6-7}, publisher = {Springer}, address = {Berlin}, pages = {459 -- 466}, year = {2015}, abstract = {Due to their anion exchange characteristics, layered double hydroxides (LDHs) are suitable for the detoxification of aqueous, fatty acid containing fermentation substrates. The aim of this study is to examine the adsorption mechanism, using crude glycerol from plant oil esterification as a model system. Changes in the intercalation structure in relation to the amount of fatty acids adsorbed are monitored by X-ray diffraction and infra-red spectroscopy. Additionally, calcination of LDH is investigated in order to increase the binding capacity for fatty acids. Our data propose that, at ambient temperature, fatty acids can be bound to the hydrotalcite by adsorption or in addition by intercalation, depending on fatty acid concentration. The adsorption of fatty acids from crude glycerol shows a BET-like behavior. Above a fatty acid concentration of 3.5 g L-1, intercalation of fatty acids can be shown by the appearance of an increased interlayer spacing. This observation suggests a two phase adsorption process. Calcination of LDHs allows increasing the binding capacity for fatty acids by more than six times, mainly by reduction of structural CO32-.}, language = {en} } @article{MuesgenanntKoersPrevostPaulssenetal.2023, author = {Mues genannt Koers, Lucas and Prevost, David and Paulßen, Elisabeth and Hoehr, Cornelia}, title = {Density reduction effects on the production of [11C]CO2 in Nb-body targets on a medical cyclotron}, volume = {199}, number = {Art. 110911}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.apradiso.2023.110911}, year = {2023}, abstract = {Medical isotope production of 11C is commonly performed in gaseous targets. The power deposition of the proton beam during the irradiation decreases the target density due to thermodynamic mixing and can cause an increase of penetration depth and divergence of the proton beam. In order to investigate the difference how the target-body length influences the operation conditions and the production yield, a 12 cm and a 22 cm Nb-target body containing N2/O2 gas were irradiated using a 13 MeV proton cyclotron. It was found that the density reduction has a large influence on the pressure rise during irradiation and the achievable radioactive yield. The saturation activity of [11C]CO2 for the long target (0.083 Ci/μA) is about 10\% higher than in the short target geometry (0.075 Ci/μA).}, language = {en} } @article{BergsMonakhovaDiehletal.2021, author = {Bergs, Michel and Monakhova, Yulia and Diehl, Bernd W. and Konow, Christopher and V{\"o}lkering, Georg and Pude, Ralf and Schulze, Margit}, title = {Lignins isolated via catalyst-free organosolv pulping from Miscanthus x giganteus, M. sinensis, M. robustus and M. nagara: a comparative study}, series = {Molecules}, volume = {26}, journal = {Molecules}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules26040842}, year = {2021}, abstract = {As a low-input crop, Miscanthus offers numerous advantages that, in addition to agricultural applications, permits its exploitation for energy, fuel, and material production. Depending on the Miscanthus genotype, season, and harvest time as well as plant component (leaf versus stem), correlations between structure and properties of the corresponding isolated lignins differ. Here, a comparative study is presented between lignins isolated from M. x giganteus, M. sinensis, M. robustus and M. nagara using a catalyst-free organosolv pulping process. The lignins from different plant constituents are also compared regarding their similarities and differences regarding monolignol ratio and important linkages. Results showed that the plant genotype has the weakest influence on monolignol content and interunit linkages. In contrast, structural differences are more significant among lignins of different harvest time and/or season. Analyses were performed using fast and simple methods such as nuclear magnetic resonance (NMR) spectroscopy. Data was assigned to four different linkages (A: β-O-4 linkage, B: phenylcoumaran, C: resinol, D: β-unsaturated ester). In conclusion, A content is particularly high in leaf-derived lignins at just under 70\% and significantly lower in stem and mixture lignins at around 60\% and almost 65\%. The second most common linkage pattern is D in all isolated lignins, the proportion of which is also strongly dependent on the crop portion. Both stem and mixture lignins, have a relatively high share of approximately 20\% or more (maximum is M. sinensis Sin2 with over 30\%). In the leaf-derived lignins, the proportions are significantly lower on average. Stem samples should be chosen if the highest possible lignin content is desired, specifically from the M. x giganteus genotype, which revealed lignin contents up to 27\%. Due to the better frost resistance and higher stem stability, M. nagara offers some advantages compared to M. x giganteus. Miscanthus crops are shown to be very attractive lignocellulose feedstock (LCF) for second generation biorefineries and lignin generation in Europe.}, language = {en} } @article{BurgerRumpfDoetal.2021, author = {Burger, Ren{\´e} and Rumpf, Jessica and Do, Xuan Tung and Monakhova, Yulia and Diehl, Bernd W. K. and Rehahn, Matthias and Schulze, Margit}, title = {Is NMR combined with multivariate regression applicable for the molecular weight determination of randomly cross-linked polymers such as lignin?}, series = {ACS Omega}, volume = {6}, journal = {ACS Omega}, number = {44}, publisher = {ACS Publications}, address = {Washington, DC}, issn = {2470-1343}, doi = {10.1021/acsomega.1c03574}, pages = {29516 -- 29524}, year = {2021}, abstract = {The molecular weight properties of lignins are one of the key elements that need to be analyzed for a successful industrial application of these promising biopolymers. In this study, the use of 1H NMR as well as diffusion-ordered spectroscopy (DOSY NMR), combined with multivariate regression methods, was investigated for the determination of the molecular weight (Mw and Mn) and the polydispersity of organosolv lignins (n = 53, Miscanthus x giganteus, Paulownia tomentosa, and Silphium perfoliatum). The suitability of the models was demonstrated by cross validation (CV) as well as by an independent validation set of samples from different biomass origins (beech wood and wheat straw). CV errors of ca. 7-9 and 14-16\% were achieved for all parameters with the models from the 1H NMR spectra and the DOSY NMR data, respectively. The prediction errors for the validation samples were in a similar range for the partial least squares model from the 1H NMR data and for a multiple linear regression using the DOSY NMR data. The results indicate the usefulness of NMR measurements combined with multivariate regression methods as a potential alternative to more time-consuming methods such as gel permeation chromatography.}, language = {en} }