@article{WallerBraunHojdisetal.2007, author = {Waller, Mark P. and Braun, Heiko and Hojdis, Nils and B{\"u}hl, Michael}, title = {Geometries of Second-Row Transition-Metal Complexes from Density-Functional Theory}, series = {Journal of Chemical Theory and Computation}, volume = {3}, journal = {Journal of Chemical Theory and Computation}, number = {6}, issn = {1549-9626}, doi = {10.1021/ct700178y}, pages = {2234 -- 2242}, year = {2007}, language = {en} } @article{SvaneborgKarimiVarzanehHojdisetal.2018, author = {Svaneborg, Carsten and Karimi-Varzaneh, Hossein Ali and Hojdis, Nils and Fleck, Franz and Everaers, Ralf}, title = {Kremer-Grest Models for Universal Properties of Specific Common Polymer Species}, series = {Soft Condensed Matter}, journal = {Soft Condensed Matter}, number = {1606.05008}, year = {2018}, abstract = {The Kremer-Grest (KG) bead-spring model is a near standard in Molecular Dynamic simulations of generic polymer properties. It owes its popularity to its computational efficiency, rather than its ability to represent specific polymer species and conditions. Here we investigate how to adapt the model to match the universal properties of a wide range of chemical polymers species. For this purpose we vary a single parameter originally introduced by Faller and M{\"u}ller-Plathe, the chain stiffness. Examples include polystyrene, polyethylene, polypropylene, cis-polyisoprene, polydimethylsiloxane, polyethyleneoxide and styrene-butadiene rubber. We do this by matching the number of Kuhn segments per chain and the number of Kuhn segments per cubic Kuhn volume for the polymer species and for the Kremer-Grest model. We also derive mapping relations for converting KG model units back to physical units, in particular we obtain the entanglement time for the KG model as function of stiffness allowing for a time mapping. To test these relations, we generate large equilibrated well entangled polymer melts, and measure the entanglement moduli using a static primitive-path analysis of the entangled melt structure as well as by simulations of step-strain deformation of the model melts. The obtained moduli for our model polymer melts are in good agreement with the experimentally expected moduli.}, language = {en} } @article{MayerHentschkeHageretal.2017, author = {Mayer, Jan and Hentschke, Reinhard and Hager, Jonathan and Hojdis, Nils and Karimi-Varnaneh, Hossein Ali}, title = {A Nano-Mechanical Instability as Primary Contribution to Rolling Resistance}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, number = {Article number 11275}, publisher = {Springer}, address = {Berlin}, issn = {2045-2322}, year = {2017}, language = {en} } @book{LauthKowalczyk2015, author = {Lauth, Jakob and Kowalczyk, J{\"u}rgen}, title = {Thermodynamik : eine Einf{\"u}hrung}, publisher = {Springer Spektrum}, address = {Berlin}, isbn = {978-3-662-46228-7}, doi = {10.1007/978-3-662-46229-4}, pages = {XVIII, 380 S.: Ill., graph. Darst.}, year = {2015}, language = {de} } @article{EngelHoltmannUlberetal.2018, author = {Engel, Mareike and Holtmann, Dirk and Ulber, Roland and Tippk{\"o}tter, Nils}, title = {Increased Biobutanol Production by Mediator-Less Electro-Fermentation}, series = {Biotechnology Journal}, volume = {14}, journal = {Biotechnology Journal}, number = {4}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1860-7314}, doi = {10.1002/biot.201800514}, year = {2018}, abstract = {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.}, language = {en} } @article{EckertAbbasiMangetal.2020, author = {Eckert, Alexander and Abbasi, Mozhdeh and Mang, Thomas and Saalw{\"a}chter, Kay and Walther, Andreas}, title = {Structure, Mechanical Properties, and Dynamics of Polyethylenoxide/Nanoclay Nacre-Mimetic Nanocomposites}, series = {Macromolecules}, volume = {53}, journal = {Macromolecules}, number = {5}, publisher = {ACS Publications}, address = {Washington, DC}, issn = {1520-5835}, doi = {10.1021/acs.macromol.9b01931}, pages = {1716 -- 1725}, year = {2020}, abstract = {Nacre-mimetic nanocomposites based on high fractions of synthetic high-aspect-ratio nanoclays in combination with polymers are continuously pushing boundaries for advanced material properties, such as high barrier against oxygen, extraordinary mechanical behavior, fire shielding, and glass-like transparency. Additionally, they provide interesting model systems to study polymers under nanoconfinement due to the well-defined layered nanocomposite arrangement. Although the general behavior in terms of forming such layered nanocomposite materials using evaporative self-assembly and controlling the nanoclay gallery spacing by the nanoclay/polymer ratio is understood, some combinations of polymer matrices and nanoclay reinforcement do not comply with the established models. Here, we demonstrate a thorough characterization and analysis of such an unusual polymer/nanoclay pair that falls outside of the general behavior. Poly(ethylene oxide) (PEO) and sodium fluorohectorite form nacre-mimetic, lamellar nanocomposites that are completely transparent and show high mechanical stiffness and high gas barrier, but there is only limited expansion of the nanoclay gallery spacing when adding increasing amounts of polymer. This behavior is maintained for molecular weights of PEO varied over four orders of magnitude and can be traced back to depletion forces. By careful investigation via X-ray diffraction and proton low-resolution solid-state NMR, we are able to quantify the amount of mobile and immobilized polymer species in between the nanoclay galleries and around proposed tactoid stacks embedded in a PEO matrix. We further elucidate the unusual confined polymer dynamics, indicating a relevant role of specific surface interactions.}, 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{LowisFergusonPaulssenetal.2021, author = {Lowis, Carsten and Ferguson, Simon and Paulßen, Elisabeth and Hoehr, Cornelia}, title = {Improved Sc-44 production in a siphon-style liquid target on a medical cyclotron}, series = {Applied Radiation and Isotopes}, volume = {172}, journal = {Applied Radiation and Isotopes}, number = {Art. 109675}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0969-8043}, doi = {10.1016/j.apradiso.2021.109675}, year = {2021}, language = {en} } @article{BechtSchollmayerMonakhovaetal.2021, author = {Becht, Alexander and Schollmayer, Curd and Monakhova, Yulia and Holzgrabe, Ulrike}, title = {Tracing the origin of paracetamol tablets by near-infrared, mid-infrared, and nuclear magnetic resonance spectroscopy using principal component analysis and linear discriminant analysis}, series = {Analytical and Bioanalytical Chemistry}, volume = {413}, journal = {Analytical and Bioanalytical Chemistry}, publisher = {Springer Nature}, issn = {1618-2650}, doi = {10.1007/s00216-021-03249-z}, pages = {3107 -- 3118}, year = {2021}, abstract = {Most drugs are no longer produced in their own countries by the pharmaceutical companies, but by contract manufacturers or at manufacturing sites in countries that can produce more cheaply. This not only makes it difficult to trace them back but also leaves room for criminal organizations to fake them unnoticed. For these reasons, it is becoming increasingly difficult to determine the exact origin of drugs. The goal of this work was to investigate how exactly this is possible by using different spectroscopic methods like nuclear magnetic resonance and near- and mid-infrared spectroscopy in combination with multivariate data analysis. As an example, 56 out of 64 different paracetamol preparations, collected from 19 countries around the world, were chosen to investigate whether it is possible to determine the pharmaceutical company, manufacturing site, or country of origin. By means of suitable pre-processing of the spectra and the different information contained in each method, principal component analysis was able to evaluate manufacturing relationships between individual companies and to differentiate between production sites or formulations. Linear discriminant analysis showed different results depending on the spectral method and purpose. For all spectroscopic methods, it was found that the classification of the preparations to their manufacturer achieves better results than the classification to their pharmaceutical company. The best results were obtained with nuclear magnetic resonance and near-infrared data, with 94.6\%/99.6\% and 98.7/100\% of the spectra of the preparations correctly assigned to their pharmaceutical company or manufacturer.}, language = {en} } @book{Lauth2022, author = {Lauth, Jakob}, title = {Physikalische Chemie kompakt}, publisher = {Springer Spektrum}, address = {Berlin}, isbn = {978-3-662-64587-1}, doi = {https://doi.org/10.1007/978-3-662-64588-8}, pages = {XXIV, 263 Seiten}, year = {2022}, language = {de} } @article{NiedermeierPennerUsherovichetal.2023, author = {Niedermeier, Jana and Penner, Crystal and Usherovich, Samuel and B{\´e}langer-Champagne, Camille and Paulßen, Elisabeth and Hoehr, Cornelia}, title = {Optical Fibers as Dosimeter Detectors for Mixed Proton/Neutron Fields - A Biological Dosimeter}, series = {electronics}, volume = {12}, journal = {electronics}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2079-9292}, doi = {10.3390/electronics12020324}, pages = {11 Seiten}, year = {2023}, abstract = {In recent years, proton therapy has gained importance as a cancer treatment modality due to its conformality with the tumor and the sparing of healthy tissue. However, in the interaction of the protons with the beam line elements and patient tissues, potentially harmful secondary neutrons are always generated. To ensure that this neutron dose is as low as possible, treatment plans could be created to also account for and minimize the neutron dose. To monitor such a treatment plan, a compact, easy to use, and inexpensive dosimeter must be developed that not only measures the physical dose, but which can also distinguish between proton and neutron contributions. To that end, plastic optical fibers with scintillation materials (Gd₂O₂S:Tb, Gd₂O₂S:Eu, and YVO₄:Eu) were irradiated with protons and neutrons. It was confirmed that sensors with different scintillation materials have different sensitivities to protons and neutrons. A combination of these three scintillators can be used to build a detector array to create a biological dosimeter.}, language = {en} } @article{PennerUsherovichNiedermeieretal.2022, author = {Penner, Crystal and Usherovich, Samuel and Niedermeier, Jana and B{\´e}langer-Champagne, Camille and Trinczek, Michael and Paulßen, Elisabeth and Hoehr, Cornelia}, title = {Organic Scintillator-Fibre Sensors for Proton Therapy Dosimetry: SCSF-3HF and EJ-260}, series = {electronics}, volume = {12}, journal = {electronics}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {2079-9292}, doi = {10.3390/electronics12010011}, pages = {12 Seiten}, year = {2022}, abstract = {In proton therapy, the dose from secondary neutrons to the patient can contribute to side effects and the creation of secondary cancer. A simple and fast detection system to distinguish between dose from protons and neutrons both in pretreatment verification as well as potentially in vivo monitoring is needed to minimize dose from secondary neutrons. Two 3 mm long, 1 mm diameter organic scintillators were tested for candidacy to be used in a proton-neutron discrimination detector. The SCSF-3HF (1500) scintillating fibre (Kuraray Co. Chiyoda-ku, Tokyo, Japan) and EJ-260 plastic scintillator (Eljen Technology, Sweetwater, TX, USA) were irradiated at the TRIUMF Neutron Facility and the Proton Therapy Research Centre. In the proton beam, we compared the raw Bragg peak and spread-out Bragg peak response to the industry standard Markus chamber detector. Both scintillator sensors exhibited quenching at high LET in the Bragg peak, presenting a peak-to-entrance ratio of 2.59 for the EJ-260 and 2.63 for the SCSF-3HF fibre, compared to 3.70 for the Markus chamber. The SCSF-3HF sensor demonstrated 1.3 times the sensitivity to protons and 3 times the sensitivity to neutrons as compared to the EJ-260 sensor. Combined with our equations relating neutron and proton contributions to dose during proton irradiations, and the application of Birks' quenching correction, these fibres provide valid candidates for inexpensive and replicable proton-neutron discrimination detectors}, language = {en} } @article{HaegerGrankinWagner2023, author = {Haeger, Gerrit and Grankin, Alina and Wagner, Michaela}, title = {Construction of an Aspergillus oryzae triple amylase deletion mutant as a chassis to evaluate industrially relevant amylases using multiplex CRISPR/Cas9 editing technology}, series = {Applied Research}, journal = {Applied Research}, number = {Early View}, publisher = {Wiley-VCH}, issn = {2702-4288}, doi = {10.1002/appl.202200106}, pages = {1 -- 15}, year = {2023}, abstract = {Aspergillus oryzae is an industrially relevant organism for the secretory production of heterologous enzymes, especially amylases. The activities of potential heterologous amylases, however, cannot be quantified directly from the supernatant due to the high background activity of native α-amylase. This activity is caused by the gene products of amyA, amyB, and amyC. In this study, an in vitro CRISPR/Cas9 system was established in A. oryzae to delete these genes simultaneously. First, pyrG of A. oryzae NSAR1 was mutated by exploiting NHEJ to generate a counter-selection marker. Next, all amylase genes were deleted simultaneously by co-transforming a repair template carrying pyrG of Aspergillus nidulans and flanking sequences of amylase gene loci. The rate of obtained triple knock-outs was 47\%. We showed that triple knockouts do not retain any amylase activity in the supernatant. The established in vitro CRISPR/Cas9 system was used to achieve sequence-specific knock-in of target genes. The system was intended to incorporate a single copy of the gene of interest into the desired host for the development of screening methods. Therefore, an integration cassette for the heterologous Fpi amylase was designed to specifically target the amyB locus. The site-specific integration rate of the plasmid was 78\%, with exceptional additional integrations. Integration frequency was assessed via qPCR and directly correlated with heterologous amylase activity. Hence, we could compare the efficiency between two different signal peptides. In summary, we present a strategy to exploit CRISPR/Cas9 for gene mutation, multiplex knock-out, and the targeted knock-in of an expression cassette in A. oryzae. Our system provides straightforward strain engineering and paves the way for development of fungal screening systems.}, language = {en} } @article{FalkenbergBottBongaertsetal.2022, author = {Falkenberg, Fabian and Bott, Michael and Bongaerts, Johannes and Siegert, Petra}, title = {Phylogenetic survey of the subtilase family and a data-mining-based search for new subtilisins from Bacillaceae}, series = {Frontiers in Microbiology}, volume = {2022}, journal = {Frontiers in Microbiology}, number = {13}, publisher = {Frontiers}, address = {Lausanne}, issn = {1664-302X}, doi = {10.3389/fmicb.2022.1017978}, pages = {Artikel 13:1017978}, year = {2022}, abstract = {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.}, language = {en} } @article{HaegerBongaertsSiegert2022, author = {Haeger, Gerrit and Bongaerts, Johannes and Siegert, Petra}, title = {A convenient ninhydrin assay in 96-well format for amino acid-releasing enzymes using an air-stable reagent}, series = {Analytical Biochemistry}, journal = {Analytical Biochemistry}, number = {624}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1096-0309}, doi = {10.1016/j.ab.2022.114819}, pages = {Artikel 114819}, year = {2022}, abstract = {An improved and convenient ninhydrin assay for aminoacylase activity measurements was developed using the commercial EZ Nin™ reagent. Alternative reagents from literature were also evaluated and compared. The addition of DMSO to the reagent enhanced the solubility of Ruhemann's purple (RP). Furthermore, we found that the use of a basic, aqueous buffer enhances stability of RP. An acidic protocol for the quantification of lysine was developed by addition of glacial acetic acid. The assay allows for parallel processing in a 96-well format with measurements microtiter plates.}, language = {en} } @article{WeldenSeverinsPoghossianetal.2022, author = {Welden, Melanie and Severins, Robin and Poghossian, Arshak and Wege, Christina and Bongaerts, Johannes and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor}, series = {Chemosensors}, volume = {10}, journal = {Chemosensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2227-9040}, doi = {10.3390/chemosensors10060218}, pages = {Artikel 218}, year = {2022}, abstract = {Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and trained staff, and do not allow for online monitoring. In this work, a capacitive electrolyte-insulator-semiconductor sensor modified with tobacco mosaic virus (TMV) particles as enzyme nanocarriers for the detection of acetoin and diacetyl is presented. The enzyme acetoin reductase from Alkalihalobacillus clausii DSM 8716ᵀ is immobilized via biotin-streptavidin affinity, binding to the surface of the TMV particles. The TMV-assisted biosensor is electrochemically characterized by means of leakage-current, capacitance-voltage, and constant capacitance measurements. In this paper, the novel biosensor is studied regarding its sensitivity and long-term stability in buffer solution. Moreover, the TMV-assisted capacitive field-effect sensor is applied for the detection of diacetyl for the first time. The measurement of acetoin and diacetyl with the same sensor setup is demonstrated. Finally, the successive detection of acetoin and diacetyl in buffer and in diluted beer is studied by tuning the sensitivity of the biosensor using the pH value of the measurement solution.}, language = {en} } @article{OjovanSteinmetz2022, author = {Ojovan, Michael I. and Steinmetz, Hans-J{\"u}rgen}, title = {Approaches to Disposal of Nuclear Waste}, series = {Energies}, volume = {15}, journal = {Energies}, number = {20}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {10.3390/en15207804}, pages = {Artikel 7804}, year = {2022}, abstract = {We present a concise mini overview on the approaches to the disposal of nuclear waste currently used or deployed. The disposal of nuclear waste is the end point of nuclear waste management (NWM) activities and is the emplacement of waste in an appropriate facility without the intention to retrieve it. The IAEA has developed an internationally accepted classification scheme based on the end points of NWM, which is used as guidance. Retention times needed for safe isolation of waste radionuclides are estimated based on the radiotoxicity of nuclear waste. Disposal facilities usually rely on a multi-barrier defence system to isolate the waste from the biosphere, which comprises the natural geological barrier and the engineered barrier system. Disposal facilities could be of a trench type, vaults, tunnels, shafts, boreholes, or mined repositories. A graded approach relates the depth of the disposal facilities' location with the level of hazard. Disposal practices demonstrate the reliability of nuclear waste disposal with minimal expected impacts on the environment and humans.}, language = {en} } @article{ZhantlessovaSavitskayaKistaubayevaetal.2022, author = {Zhantlessova, Sirina and Savitskaya, Irina and Kistaubayeva, Aida and Ignatova, Ludmila and Talipova, Aizhan and Pogrebnjak, Alexander and Digel, Ilya}, title = {Advanced "Green" prebiotic composite of bacterial cellulose/pullulan based on synthetic biology-powered microbial coculture strategy}, series = {Polymers}, volume = {14}, journal = {Polymers}, number = {15}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, doi = {10.3390/polym14153224}, pages = {Artikel 3224}, year = {2022}, abstract = {Bacterial cellulose (BC) is a biopolymer produced by different microorganisms, but in biotechnological practice, Komagataeibacter xylinus is used. The micro- and nanofibrillar structure of BC, which forms many different-sized pores, creates prerequisites for the introduction of other polymers into it, including those synthesized by other microorganisms. The study aims to develop a cocultivation system of BC and prebiotic producers to obtain BC-based composite material with prebiotic activity. In this study, pullulan (PUL) was found to stimulate the growth of the probiotic strain Lactobacillus rhamnosus GG better than the other microbial polysaccharides gellan and xanthan. BC/PUL biocomposite with prebiotic properties was obtained by cocultivation of Komagataeibacter xylinus and Aureobasidium pullulans, BC and PUL producers respectively, on molasses medium. The inclusion of PUL in BC is proved gravimetrically by scanning electron microscopy and by Fourier transformed infrared spectroscopy. Cocultivation demonstrated a composite effect on the aggregation and binding of BC fibers, which led to a significant improvement in mechanical properties. The developed approach for "grafting" of prebiotic activity on BC allows preparation of environmentally friendly composites of better quality.}, language = {en} } @article{WeldenPoghossianVahidpouretal.2022, author = {Welden, Melanie and Poghossian, Arshak and Vahidpour, Farnoosh and Wendlandt, Tim and Keusgen, Michael and Wege, Christina and Sch{\"o}ning, Michael Josef}, title = {Towards multi-analyte detection with field-effect capacitors modified with tobacco mosaic virus bioparticles as enzyme nanocarriers}, series = {Biosensors}, volume = {12}, journal = {Biosensors}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {2079-6374}, doi = {10.3390/bios12010043}, pages = {Artikel 43}, year = {2022}, abstract = {Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In the present work, tobacco mosaic virus (TMV) particles were applied for the co-immobilization of penicillinase and urease onto the gate surface of a field-effect electrolyte-insulator-semiconductor capacitor (EISCAP) with a p-Si-SiO₂-Ta₂O₅ layer structure for the sequential detection of penicillin and urea. The TMV-assisted bi-enzyme EISCAP biosensor exhibited a high urea and penicillin sensitivity of 54 and 85 mV/dec, respectively, in the concentration range of 0.1-3 mM. For comparison, the characteristics of single-enzyme EISCAP biosensors modified with TMV particles immobilized with either penicillinase or urease were also investigated. The surface morphology of the TMV-modified Ta₂O₅-gate was analyzed by scanning electron microscopy. Additionally, the bi-enzyme EISCAP was applied to mimic an XOR (Exclusive OR) enzyme logic gate.}, language = {en} } @article{WeldenJablonskiWegeetal.2021, author = {Welden, Rene and Jablonski, Melanie and Wege, Christina and Keusgen, Michael and Wagner, Patrick Hermann and Wagner, Torsten and Sch{\"o}ning, Michael Josef}, title = {Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase}, series = {Biosensors}, volume = {11}, journal = {Biosensors}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2079-6374}, doi = {10.3390/bios11060171}, pages = {Artikel 171}, year = {2021}, abstract = {The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte's pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS.}, language = {en} } @book{Lauth2023, author = {Lauth, Jakob}, title = {Physical chemistry in a nutshell: Basics for engineers and scientists}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-662-67636-3 (Softcover)}, doi = {10.1007/978-3-662-67637-0}, pages = {XIII, 248 Seiten}, year = {2023}, abstract = {This book is based on a multimedia course for biological and chemical engineers, which is designed to trigger students' curiosity and initiative. A solid basic knowledge of thermodynamics and kinetics is necessary for understanding many technical, chemical, and biological processes. The one-semester basic lecture course was divided into 12 workshops (chapters). Each chapter covers a practically relevant area of physical chemistry and contains the following didactic elements that make this book particularly exciting and understandable: - Links to Videos at the start of each chapter as preparation for the workshop - Key terms (in bold) for further research of your own - Comprehension questions and calculation exercises with solutions as learning checks - Key illustrations as simple, easy-to-replicate blackboard pictures Humorous cartoons for each workshop (by Faelis) additionally lighten up the text and facilitate the learning process as a mnemonic. To round out the book, the appendix includes a summary of the most popular experiments in basic physical chemistry courses, as well as suggestions for designing workshops with exhibits, experiments, and "questions of the day." Suitable for students minoring in chemistry; chemistry majors are sure to find this slimmed-down, didactically valuable book helpful as well. The book is excellent for self-study.}, language = {en} } @article{DellmannGloriusLitvinovetal.2023, author = {Dellmann, Sophia Florence and Glorius, J. and Litvinov, Yu A. and Reifarth, R. and Al-Khasawneh, Kafa and Aliotta, M. and Bott, L. and Br{\"u}ckner, Benjamin and Bruno, C. G. and Chen, Ruijiu and Davinson, T. and Dickel, T. and Dillmann, Iris and Dmytriev, D. and Erbacher, P. and Freire-Fern{\´a}ndez, D. and Forstner, Oliver and Geissel, H. and G{\"o}bel, K. and Griffin, Christopher J. and Grisenti, R. and Gumberidze, Alexandre and Haettner, Emma and Hagmann, Siegbert and Heil, M. and Heß, R. and Hillenbrand, P.-M. and Joseph, R. and Jurado, B. and Kozhuharov, Christophor and Kulikov, I. and L{\"o}her, Bastian and Langer, Christoph and Leckenby, Guy and Lederer-Woods, C. and Lestinsky, M. and Litvinov, S. A. and Lorenz, B. A. and Lorenz, E. and Marsh, J. and Menz, Esther Babette and Morgenroth, T. and Petridis, N. and Pibernat, Jerome and Popp, U. and Psaltis, Athanasios and Sanjari, Shahab and Scheidenberger, C. and Sguazzin, M. and Sidhu, Ragandeep Singh and Spillmann, Uwe and Steck, M. and St{\"o}hlker, T. and Surzhykov, A. and Swartz, J. A. and T{\"o}rnqvist, H. and Varga, L. and Vescovi, Diego and Weick, H. and Weigand, M. and Woods, P. and Xing, Y. and Yamaguchi, Taiyo}, title = {Proton capture on stored radioactive ¹¹⁸Te ions}, series = {EPJ Web of Conferences}, volume = {279}, journal = {EPJ Web of Conferences}, number = {Article Number: 11018}, publisher = {EDP Sciences}, issn = {2100-014X}, doi = {10.1051/epjconf/202327911018}, pages = {1 -- 5}, year = {2023}, abstract = {Experimental determination of the cross sections of proton capture on radioactive nuclei is extremely difficult. Therefore, it is of substantial interest for the understanding of the production of the p-nuclei. For the first time, a direct measurement of proton-capture cross sections on stored, radioactive ions became possible in an energy range of interest for nuclear astrophysics. The experiment was performed at the Experimental Storage Ring (ESR) at GSI by making use of a sensitive method to measure (p,γ) and (p,n) reactions in inverse kinematics. These reaction channels are of high relevance for the nucleosyn-thesis processes in supernovae, which are among the most violent explosions in the universe and are not yet well understood. The cross section of the ¹¹⁸Te(p,γ) reaction has been measured at energies of 6 MeV/u and 7 MeV/u. The heavy ions interacted with a hydrogen gas jet target. The radiative recombination process of the fully stripped ¹¹⁸Te ions and electrons from the hydrogen target was used as a luminosity monitor. An overview of the experimental method and preliminary results from the ongoing analysis will be presented.}, language = {en} } @techreport{HaegerBongaertsSiegert2023, author = {Haeger, Gerrit and Bongaerts, Johannes and Siegert, Petra}, title = {Abschlussbericht Teil II: Eingehende Darstellung Neue biobasierte Lipopeptide aus nachhaltiger Produktion (LipoPep)}, pages = {17Seiten}, year = {2023}, language = {de} } @article{TrappLammersEngudaretal.2023, author = {Trapp, Svenja and Lammers, Tom and Engudar, Gokce and Hoehr, Cornelia and Denkova, Antonia G. and Paulßen, Elisabeth and de Kruijff, Robin M.}, title = {Membrane-based microfluidic solvent extraction of Ga-68 from aqueous Zn solutions: towards an automated cyclotron production loop}, series = {EJNMMI Radiopharmacy and Chemistry}, volume = {2023}, journal = {EJNMMI Radiopharmacy and Chemistry}, number = {8, Article number: 9}, publisher = {Springer Nature}, issn = {2365-421X}, doi = {10.1186/s41181-023-00195-2}, pages = {1 -- 14}, year = {2023}, language = {en} } @unpublished{GreinerJerominSitholeetal.2023, author = {Greiner, Lasse and Jeromin, G{\"u}nter Erich and Sithole, Patience and Petersen, Soenke}, title = {Preprint: Studies on the enzymatic reduction of levulinic acid using Chiralidon-R and Chiralidon-S}, series = {ChemRxiv}, journal = {ChemRxiv}, doi = {10.26434/chemrxiv-2023-jlvcv}, pages = {13 Seiten}, year = {2023}, abstract = {The enzymatic reduction of levulinic acid by the chiral catalysts Chiralidon-R and Chiralidon-S which are commercially available superabsorbed alcohol dehydrogenases is described. The Chiralidon®-R/S reduces the levulinic acid to the (R,S)-4-hydroxy valeric acid and the (R)- or (S)- gamma-valerolactone.}, language = {en} } @article{ElBerguiAbouabdillahBouriougetal.2023, author = {El Bergui, Omnia and Abouabdillah, Aziz and Bourioug, Mohamed and Schmitz, Dominik and Biel, Markus and Aboudrare, Abdellah and Krauss, Manuel and Jomaa, Ahlem and Romuli, Sebastian and M{\"u}ller, Joachim and Fagroud, Mustapha and Bouabid, Rachid}, title = {Innovative solutions for drought: Evaluating hydrogel application on onion cultivation (Allium cepa) in Morocco}, series = {Water}, volume = {15}, journal = {Water}, number = {11}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/w15111972}, pages = {Artikel 1972}, year = {2023}, abstract = {Throughout the last decade, and particularly in 2022, water scarcity has become a critical concern in Morocco and other Mediterranean countries. The lack of rainfall during spring was worsened by a succession of heat waves during the summer. To address this drought, innovative solutions, including the use of new technologies such as hydrogels, will be essential to transform agriculture. This paper presents the findings of a study that evaluated the impact of hydrogel application on onion (Allium cepa) cultivation in Meknes, Morocco. The treatments investigated in this study comprised two different types of hydrogel-based soil additives (Arbovit® polyacrylate and Huminsorb® polyacrylate), applied at two rates (30 and 20 kg/ha), and irrigated at two levels of water supply (100\% and 50\% of daily crop evapotranspiration; ETc). Two control treatments were included, without hydrogel application and with both water amounts. The experiment was conducted in an open field using a completely randomized design. The results indicated a significant impact of both hydrogel-type dose and water dose on onion plant growth, as evidenced by various vegetation parameters. Among the hydrogels tested, Huminsorb® Polyacrylate produced the most favorable outcomes, with treatment T9 (100\%, HP, 30 kg/ha) yielding 70.55 t/ha; this represented an increase of 11 t/ha as compared to the 100\% ETc treatment without hydrogel application. Moreover, the combination of hydrogel application with 50\% ETc water stress showed promising results, with treatment T4 (HP, 30 kg, 50\%) producing almost the same yield as the 100\% ETc treatment without hydrogel while saving 208 mm of water.}, language = {en} } @misc{BraunKrafftTippkoetter2022, author = {Braun, Lena and Krafft, Simone and Tippk{\"o}tter, Nils}, title = {Combined supercritical carbon dioxide extraction and chromatography of the algae fatty linoleic and linolenic acid}, series = {Chemie Ingenieur Technik}, volume = {94}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.202255308}, pages = {1304}, year = {2022}, abstract = {A method for the integrated extraction and separation of fatty acids from algae using supercritical CO2 is presented. Desmodesmus obliquus and Chlorella sorokiniana were used as algae. First, a method for chromatographic separation of fatty acids of different degrees of saturation was established and optimized. Then, an integrated method for supercritical extraction was developed for both algal species. It was also verified whether prior cell disruption was beneficial for extraction. In developing the method for chromatographic separation, statistical experimental design was used to determine the optimal parameter settings. The methanol content in the mobile phase proved to be the most important parameter for successful separation of the three unsaturated fatty acids oleic acid, linoleic acid, and linolenic acid. Supercritical extraction with dried algae showed that about four times more fatty acids can be extracted from C. sorokiniana relative to the dry mass used.}, language = {en} } @misc{KrafftKukaUlberetal.2022, author = {Krafft, Simone and Kuka, Katrin and Ulber, Roland and Tippk{\"o}tter, Nils}, title = {Utilization of Lolium perenne varieties as a renewable substrate for single-cell proteins, lactate, and composite materials}, series = {Chemie Ingenieur Technik}, volume = {94}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.202255306}, pages = {1303 -- 1304}, year = {2022}, abstract = {Lolium perenne (perennial ryegrass) is aproductive and high-quality forage grass indigenous to Southern Europe, temperate Asia, and North Africa. Nowadays it is widespread and the dominant grass species on green areas in temperate climates. This abundant source of biomass is suitable for the development of bioeconomic processes because of its high cellulose and water-soluble carbohydrate content. In this work, novel breeds of the perennial ryegrass are being examined with regards to their quality parameters and biotechnological utilization options within the context of bioeconomy. Three processing operations are presented. In the first process, the perennial ryegrass is pretreated by pressing or hydrothermal extraction to derive glucosevia subsequent enzymatic hydrolysis of cellulose. A yield of up to 82 \% glucose was achieved when using the hydrothermal ex-traction as pretreatment. In a second process, the ryegrass is used to produce lactic acid in high concentrations. The influence of the growth conditions and the cutting time on the carboxylic acid yield is investigated. A yield of lactic acid of above 150 g kg⁻¹ dry matter was achieved. The third process is to use Lolium perenne as a substrate in the fermentation of K. marxianus for the microbial production of single-cell proteins. The perennial ryegrass is screw-pressed and the press juice is used as medium. When supplementing the press juice with yeast media components, a biomass concentration of up to 16 g L⁻¹ could be achieved.}, language = {en} } @misc{VarrialeKukaTippkoetteretal.2022, author = {Varriale, Ludovica and Kuka, Katrin and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Use of a green biomass in a biorefinery platform}, series = {Chemie Ingenieur Technik}, volume = {94}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.202255095}, pages = {1299}, year = {2022}, abstract = {The emerging environmental issues due to the use of fossil resources are encouraging the exploration of new renewable resources. Biomasses are attracting more interest due to the low environmental impacts, low costs, and high availability on earth. In this scenario, green biorefineries are a promising platform in which green biomasses are used as feedstock. Grasses are mainly composed of cellulose and hemicellulose, and lignin is available in a small amount. In this work, a perennial ryegrass was used as feedstock to develop a green bio-refinery platform. Firstly, the grass was mechanically pretreated, thus obtaining a press juice and a press cake fraction. The press juice has high nutritional values and can be employed as part of fermentation media. The press cake can be employed as a substrate either in enzymatic hydrolysis or in solid-state fermentation. The overall aim of this work was to demonstrate different applications of both the liquid and the solid fractions. For this purpose, the filamentous fungus A. niger and the yeast Y. lipolythica were selected for their ability to produce citric acid. Finally, the possibility was assessed to use the press juice as part of fermentation media to cultivate S. cerevisiae and lactic acid bacteria for ethanol and lactic acid fermentation.}, language = {en} } @misc{RothkranzKrafftTippkoetter2022, author = {Rothkranz, Berit and Krafft, Simone and Tippk{\"o}tter, Nils}, title = {Media optimization for sustainable fuel production: How to produce biohydrogen from renewable resources with Thermotoga neapolitana}, series = {Chemie Ingenieur Technik}, volume = {94}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.202255305}, pages = {1298 -- 1299}, year = {2022}, abstract = {Hydrogen is playing an increasingly important role in research and politics as an energy carrier of the future. Since hydrogen has commonly been produced from methane by steam reforming, the need for climate-friendly, alternative production routes is emerging. In addition to electrolysis, fermentative routes for the production of so-called biohydrogen are "green" alternatives. The application of microorganisms offers the advantage of sustainable production from renewable resources using easily manageable technologies. In this project, the hyperthermophilic, anaerobic microorganism Thermotoga neapolitana is used for the productio nof biohydrogen from renewable resources. The enzymatically hydrolyzed resources were used in fermentation leading to yield coefficients of 1.8 mole H₂ per mole glucose when using hydrolyzed straw and ryegrass supplemented with medium, respectively. These results are similar to the hydrogen yields when using Thermotoga basal medium with glucose (TBGY) as control group. In order to minimize the supplementation of the hydrolysate and thus increase the economic efficiency of the process, the essential media components were identified. The experiments revealed NaCl, KCl, and glucose as essential components for cell growth as well as biohydrogen production. When excluding NaCl, a decrease of 96\% in hydrogen production occured.}, language = {en} } @techreport{Tippkoetter2021, author = {Tippk{\"o}tter, Nils}, title = {TreBec - Herstellung eines Mehrwegbechers aus Treber : Sachbericht zum Verwendungsnachweis}, publisher = {FH Aachen}, address = {J{\"u}lich}, doi = {10.2314/KXP:1858723302}, pages = {10 Seiten}, year = {2021}, abstract = {Laufzeit des Vorhabens und Berichtszeitraum: 01.10.2020-30.09.2021}, language = {de} } @misc{SiekerTippkoetterUlberetal.2010, author = {Sieker, T. and Tippk{\"o}tter, Nils and Ulber, Roland and Bart, H.-J. and Heinzle, E.}, title = {Gr{\"u}ne Bioraffinerie: Ganzheitliche Nutzung von Grassilage f{\"u}r die Herstellung von Grund-und Feinchemikalien}, series = {Chemie Ingenieur Technik}, volume = {82}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201050321}, pages = {1564}, year = {2010}, abstract = {Gras hat ein hohes Potenzial als nachwachsender Rohstoff. Bei ungeeigneter Lagerung verderben Gr{\"a}ser allerdings innerhalb weniger Tage. Dieser Nachteil kann durch die Silierung des Grasschnittes behoben werden. Eines der wichtigsten in der Silage enthaltenen Produkte ist die Milchs{\"a}ure. Um diese f{\"u}r weitere Aufarbeitungsschritte zug{\"a}nglich zu machen, wird aus der Silage ein Presssaft hergestellt. Die Milchs{\"a}ure wird aus einem Silagepresssaft mittels Extraktion durch ionische Fl{\"u}ssigkeiten isoliert. Dabei wird zum einen eine reine Milchs{\"a}ure hergestellt, die z. B. f{\"u}r die Herstellung von Polymilchs{\"a}ure genutzt werden kann. Zum anderen wird ein weniger aufgereinigter Extrakt gewonnen, der f{\"u}r die fermentative Produktion von L-Lysin und 1,2-Propandiol genutzt werden soll. Im Rahmen des Projekts erfolgt die gentechnische Optimierung von Corynebacterium glutamicum f{\"u}r die Umsetzung von Milchs{\"a}urezu L-Lysin. Die im nach der Pressung verbleibenden Presskuchen enthaltenen Grasfasern bestehen zu einem großen Teil aus Polysacchariden. Diese werden hydrolysiert und die dabei freigesetzten Zucker zu Grundchemikalien wie Ethanol oder Itakons{\"a}ure fermentiert. Im Rahmen einer vollst{\"a}ndigen Nutzung der Silage wird das Raffinat aus der Milchs{\"a}ureextraktion als Mediumsupplement in der Fermentation eingesetzt, was die Zugabe weiterer Medienbestandteile {\"u}berfl{\"u}ssig macht. Die R{\"u}ckst{\"a}nde der Hydrolysen und Fermentationen sollen dar{\"u}berhinaus f{\"u}r die Herstellung von Biogas genutzt werden.}, language = {de} } @inproceedings{EngelThieringerTippkoetter2016, author = {Engel, Mareike and Thieringer, Julia and Tippk{\"o}tter, Nils}, title = {Linking bioprocess engineering and electrochemistry for sustainable biofuel production}, series = {Young Researchers Symposium, YRS 2016. Proceedings}, booktitle = {Young Researchers Symposium, YRS 2016. Proceedings}, publisher = {Fraunhofer Verlag}, address = {Karlsruhe}, pages = {49 -- 53}, year = {2016}, abstract = {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.}, language = {en} } @misc{TippkoetterNeitmannSohlingetal.2009, author = {Tippk{\"o}tter, Nils and Neitmann, E. and Sohling, U. and Ruf, F. and Ulber, Roland}, title = {Anaerobe Produktion von ABE-L{\"o}sungsmitteln aus an Bleicherde adsorbiertem {\"O}l}, series = {Chemie Ingenieur Technik}, volume = {81}, journal = {Chemie Ingenieur Technik}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.200950075}, pages = {1217 -- 1218}, year = {2009}, abstract = {Mit Palm{\"o}l beladene Bleicherde wurde auf die Anwendbarkeit als Rohstoff zur Bildung von Aceton, Ethanol und Butanol (ABE) untersucht. Nach der Abtrennung des entf{\"a}rbten bzw. gebleichten {\"O}ls bestehen 20-40 \% (w/w) des Bleicherder{\"u}ckstands aus adsorbiertem {\"O}l. Somit stellt das Mineral einen wertvollen Rohstoff dar. Zur Produktion der L{\"o}sungsmittel wurde das gebundene {\"O}l hydrolysiert. Das freigesetzte Glycerin diente als Substrat einer nachfolgenden anaeroben Fermentation zu den ABE-L{\"o}sungsmitteln. Die Fermentationen wurden mit verschiedenen Clostridien-St{\"a}mmen durchgef{\"u}hrt, von denen einige lipolytische Aktivit{\"a}t aufweisen. Der {\"O}lgehalt der Bleicherde betrug 28 \% der Adsorbermasse. F{\"u}r die Hydrolyse wurden drei Ans{\"a}tze untersucht: 1. die direkte Fermentation des Adsorbers mit lipolytisch aktiven Clostridien, 2. der Einsatz von Lipasen und die Fermentation des resultierenden {\"U}berstands und 3. die Kofermentation mit einer lipolytisch aktiven Hefe. Jeder der drei Ans{\"a}tze f{\"u}hrte zu einerHydrolyse des {\"O}ls und Wachstum der Mikroorganismen. Der Einsatz von Lipasen resultierte in einer vollst{\"a}ndigen und der schnellsten Hydrolyse des {\"O}ls. Eine Glycerinkonzentration von 13,4 g/L konnte erreicht werden. Die anaerobe Fermentation der verschiedenen Clostridien auf Minimalmedien verlief erfolgreich. Der Vergleich der Fermentationen der Bleicherdehydrolysate zeigte, dass das Hydrolysat wachstumsinhibierende Substanzen enth{\"a}lt. Unter diesen Bedingungen konnte eine Ausbeute von Y P/S = 0,11 erzielt werden. Der Einsatz eines Ionenaustauschers zur Reinigung des Hydrolysats vor der Fermentation resultierte in einer Verbesserung des Wachstums}, language = {de} } @misc{TippkoetterMaurerPasteuretal.2010, author = {Tippk{\"o}tter, Nils and Maurer, S. and Pasteur, A. and Kampeis, P. and Ulber, Roland}, title = {Hochgradient-Magnetseparation von Fermentationsprodukten-FEM Simulation der Filtermatrix}, series = {Chemie Ingenieur Technik}, volume = {82}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201050217}, pages = {1361}, year = {2010}, abstract = {Durch den Einsatz magnetisierbarer Partikel lassen sich Stoffwechselprodukte direkt und selektiv aus feststoffreichen Fermentationssuspensionen abtrennen. Im Gegensatz zu klassischen Adsorbermaterialien k{\"o}nnen magnetisierbare Partikel mit sehr geringen Durchmessern verwendet werden. Zur deren Abtrennung ist jedoch ein hoher Magnetfeldgradient notwendig. Dieser wird in der Regel durch in der Trennkammer bzw. dem Magnetfeld eingebrachte magnetisierbare Dr{\"a}hte realisiert. Bei der Auslegung der Drahtgitter ist ein Kompromiss zwischen Abtrennrate und Durchl{\"a}ssigkeit n{\"o}tig. Die Ausrichtung der Dr{\"a}hte in Relation zum Magnetfeld, deren Abstand sowie die geometrische Anordnung k{\"o}nnen hierbei variiert werden. Zum Verst{\"a}ndnis der Einfl{\"u}sse auf das sich ausbildende Magnetfeld und die Fluiddynamik wurden Simulationen mit der Finite-Elemente-Methode durchgef{\"u}hrt und experimentell {\"u}berpr{\"u}ft. Hierf{\"u}r wurden die Dr{\"a}hte unter Variation von Anzahl, Richtung und Anordnung in den Hochgradient-Magnetseparator eingebracht. Erste Verifizierungen der Simulationen zeigen, dass die in Magnetfeldrichtung ausgerichteten Dr{\"a}hte (x-Achse) {\"u}ber die geringste Partikelr{\"u}ckhaltef{\"a}higkeit verf{\"u}gen. Die Dr{\"a}hte der y- und z-Achse halten den gr{\"o}ßten Anteil der Magnetpartikel zur{\"u}ck, wobei die Dr{\"a}hte in y-Richtung den h{\"o}chsten Feldgradienten ausbilden. Des Weiteren konnte gezeigt werden, dass eine rhomboedrische Drahtanordnung der kubischen vorzuziehen ist.}, language = {de} } @misc{DuweSchlegelTippkoetteretal.2014, author = {Duwe, A. and Schlegel, C. and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Sequentielle Extraktion von Cellulose zur effizienten Nutzung der Stoffstr{\"o}me in der Holzbioraffinerie}, series = {Chemie Ingenieur Technik}, volume = {86}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201450308}, pages = {1400}, year = {2014}, abstract = {In der Reihe der nachwachsenden Rohstoffe besitzt Holz als erneuerbare und umweltfreundliche Ressource ein großes Potenzial. {\"U}ber 11 Mio. ha Holz, das laut der Fachagentur f{\"u}r nachwachsende Rohstoffe (FNR) auch f{\"u}r industrielle Zwecke genutzt werden kann, wuchsen im Jahr 2013 allein auf bundesdeutscher Fl{\"a}che. 56,8 Mio. m³ j{\"a}hrlicher Holzeinschlag in den letzten zehn Jahren wurde zu knapp der H{\"a}lfte stofflich und der Rest energetisch verwertet. Im Rahmen dieser Arbeit konnte auf der Basis vom Holz der Buche, die nach Fichte und Kiefer die dritth{\"a}ufigste Baumart in Deutschland ist und 15\% der deutschen Waldfl{\"a}che ausmacht, die Fraktionierung der polymeren Hauptbestandteile mit niedrigem energetischen Einsatz erreicht werden. Hierbei werden in einem nachgeschalteten Extraktionsprozess die beiden Komponenten Hemicellulose und Lignin in fl{\"u}ssiger Form von der finalen festen Cellulosefraktion abgetrennt. Die Extraktion der Hemicellulose erfolgt durch eine Liquid Hot Water (LHW)-Behandlung. Untersucht wird der katalytische Zusatz anorganischer S{\"a}uren wie H₃PO₄ und H₂SO₄. Im Hinblick auf die weitere Verwertung von Lignin zu aromatischen Synthesebausteinen kommt die Organosolv-Extraktion mit einem Ethanol/Wasser-Gemisch zum Einsatz. Von Vorteil ist die weitere Verwendung beider Stoffstr{\"o}me ohne F{\"a}llungsschritt und nachteiliger Verd{\"u}nnung der Hemicellulose.}, language = {en} } @misc{MoehringWulfhorstCapitainetal.2016, author = {M{\"o}hring, S. and Wulfhorst, H. and Capitain, C. and Roth, J. and Tippk{\"o}tter, Nils}, title = {Fractioning of lignocellulosic biomass: Scale-down and automation of thermal pretreatment for parameter optimization}, series = {Chemie Ingenieur Technik}, volume = {88}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201650288}, pages = {1229}, year = {2016}, abstract = {In order to efficiently convert lignocellulose, it is often necessary to conduct a pretreatment. The biomass considered in this study typically comprises of agricultural and horticultural residues, as well as beechwood. A very environmentally friendly method, namely, fungal pretreatment using white-rot fungi, leads to an enhanced enzymatic hydrolysis. In contrast to other processes presented, the energy input is extremely low. However, the fungal growth on the lignocellulosic substrates takes several weeks at least in order to be effective. Thus, the reduction of chemicals and energy for thermal processing is a target of our current research. Liquid hot water (LHW) and solvent-based pretreatment (OrganoSolv) require more complex equipment, as they depend on high temperatures (160 - 180 °C) and enhanced pressure (up to 20 bar). However, they prove to be promising processes in regard to the fractioning of lignocellulose. For optimal lignin recovery the parameters differ from those established in cellulose extraction. A novel screening system scaled down to a reaction volume of 100 mL has been developed and successfully tested for this purpose.}, language = {en} } @misc{TippkoetterSiekerWiesenetal.2014, author = {Tippk{\"o}tter, Nils and Sieker, T. and Wiesen, S. and Duwe, A. and Roth, J. and Ulber, Roland}, title = {Simultane Saccharifizierung und Fermentierung (SSF) sowie Produktion von Aceton, Butanol, Ethanol (ABE) und Dicarbons{\"a}uren aus technischer Cellulose}, series = {Chemie Ingenieur Technik}, volume = {86}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201450297}, pages = {1518}, year = {2014}, abstract = {Technische Cellulose wurde als m{\"o}glicher Rohstoff zur fermentativen Produktbildung untersucht. Hierf{\"u}r wird Cellulose in der Lignocellulose-Bioraffinerie hergestellt und daraus Hydrolysat gewonnen. Die Pr{\"u}fung der technischen Hydrolysate als Substrate erfolgte anhand eines breiten Spektrums an Bioprodukten, von Kraftstoffen wie Ethanolund Butanol, bis zu den Dicarbons{\"a}uren Itacon- und Bernsteins{\"a}ure. Dabei werden Bakterien, Hefen und Pilze als Produktionsorganismen eingesetzt. Die einzelnen Herstellverfahren stellen unterschiedliche Anforderungen an die Substrathandhabung. Im Fall der Ethanol- und Butanol-Gewinnung kann eine simultane Saccharifizierung und Fermentierung (SSF) durchgef{\"u}hrt werden. Aufgrund der Produkttoxizit{\"a}t erfordert die Butanol-Herstellung dabei eine In-situ-Produktabtrennung durch L{\"o}semittelimpr{\"a}gnierte Partikel. Die Herstellung der beiden Dicarbons{\"a}uren unterscheidet sich in der Sensitivit{\"a}t der verwendeten Mikroorganismen gegen{\"u}ber Inhibitoren, die in Spuren im Hydrolysat enthalten sind. Die Bernteins{\"a}urebildung mit Actinobacillussuccinogenes kann mit unbehandeltem Hydrolysat erfolgen. Dagegen erfordert die Gewinnung von Itacons{\"a}ure mit A. terreus eine Detoxifizierung des Hydrolysats. Insgesamt konnte gezeigt werden, dass s{\"a}mtliche Bioraffinerie-Hydrolysate als Substrate f{\"u}r unterschiedliche Fermentationen geeignet sind.}, language = {de} } @misc{TippkoetterPasteurUlber2012, author = {Tippk{\"o}tter, Nils and Pasteur, A. and Ulber, Roland}, title = {Magnetisch abtrennbare Gold-Nanopartikel zur katalytischen Zuckeroxidation}, series = {Chemie Ingenieur Technik}, volume = {84}, journal = {Chemie Ingenieur Technik}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201250393}, pages = {1328}, year = {2012}, abstract = {Glucose ist ein prim{\"a}res Zwischenprodukt der Verarbeitung nachwachsender Rohstoffe, wie z. B. Cellulose. Die wertsteigernde Weiterverarbeitung des Monosaccharids erfolgt h{\"a}ufig in Form vonFermentationsprozessen, jedoch kann der Rohstoff auch f{\"u}r zahlreiche chemische Verarbeitungsstufen genutzt werden. Ein großtechnisch relevanter Prozess ist die Herstellung von Glucons{\"a}ure (GS), die u. a. als Nahrungsmittelzusatz (E 574) eingesetzt wird. Die Darstellung der S{\"a}ure erfolgt durch Oxidation von Glucose mit magnetisierbarem Gold-Nano-Katalysator. Die R{\"u}ckgewinnung des Katalysators aus der Reaktionsl{\"o}sung wurde unter Einwirkung eines Magnetfeldgradienten verwirklicht. Die Synthese der magnetischen Goldkatalysatoren (sowohl Tr{\"a}gerpartikel als auch Gold-Nanopartikel) wurde durch nass-chemische F{\"a}llungsreaktionen durchgef{\"u}hrt. Die Charakteristiken der neuen Materialen konnte durch Messungen des PCD-Potenzials, Laserbeugung und REM/EDX untersucht werden. So wurden u. a. Partikeldurchmesser von 25 lm und ein Goldgehaltvon 1,03 \% ermittelt. Weiterhin wurden f{\"u}r die Goldkatalysatoren optimale Reaktionsbedingungen f{\"u}r die Glucoseoxidation im geregelten R{\"u}hrkesselreaktor etabliert. Hierdurch konnten eine Produktselektivit{\"a}t von 100 \% und eine Wiederverwendbarkeit der Partikel {\"u}ber mindestens zehn Zyklen erreicht werden.}, language = {de} } @misc{WiesenTippkoetterDuweetal.2012, author = {Wiesen, S. and Tippk{\"o}tter, Nils and Duwe, A. and Ulber, Roland}, title = {Aceton-Butanol-Ethanol (ABE)-Fermentation von Organosolv-Holzhydrolysaten}, series = {Chemie Ingenieur Technik}, volume = {84}, journal = {Chemie Ingenieur Technik}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201250262}, pages = {1308}, year = {2012}, abstract = {Die L{\"o}sungsmittelherstellung durch Clostridien konnte wirtschaftlich nicht mit der chemischen Synthese von L{\"o}sungsmitteln auf Erd{\"o}lbasis konkurrieren und wurde in den fr{\"u}hen 1960er Jahren nahezu vollst{\"a}ndig eingestellt. Das Interesse an nachwachsenden Rohstoffen hat in den letzten Jahren zu einem Wiederaufleben der ABE-Fermentation gef{\"u}hrt. Aufgrund seiner h{\"o}heren Energiedichte im Vergleich zu Ethanol ist Biobutanol als Energietr{\"a}gerbesonders interessant und bietet sich z. B. als Produkt einer Bioraffinerie der 2. Generation an. F{\"u}r die beschriebenen Experimente wird durch das Organosolv-Verfahren aufgeschlossenes Buchenholz verwendet. Der Faserstoff wird mithilfe von CTec2-Enzymen hydrolysiert, wobei der erhaltene {\"U}berstand eine Glucosekonzentration von 66 g L⁻¹ aufweist. Auf der Basis dieses Materials k{\"o}nnen mit Clostridium acetobutylicum Butanol-Ausbeuten erzielt werden, die mit denen unter Verwendung von reinen Zuckern vergleichbar sind. Dem Problem der hohen Produktinhibierung wird mit einer In-situ-Produktaufarbeitung begegnet. Mithilfe von L{\"o}sungsmittelimpr{\"a}gnierten Partikeln (SIPs) kann die Produktausbeute drastisch gesteigert werden, indem die gebildeten L{\"o}sungsmittel durch das auf dem Partikel impr{\"a}gnierte L{\"o}sungsmittel w{\"a}hrend der Fermentation extrahiert werden. Zudem wird hierdurch die weitere Produktaufarbeitungstark vereinfacht.}, language = {de} } @misc{RossJonesTeumerCapitainetal.2018, author = {Ross-Jones, J. and Teumer, T. and Capitain, C. and Tippk{\"o}tter, Nils and Krause, M. J. and Methner, F.-J. and R{\"a}dle, M.}, title = {Analytical methods for in-line characterization of beer haze}, series = {Trends in Brewing}, journal = {Trends in Brewing}, year = {2018}, abstract = {In most beers, producers strive to minimize haze to maximize visual appeal. To detect the formation of particulates, a measurement system for sub-micron particles is required. Beer haze is naturally occurring, composed of protein or polyphenol particles; in their early stage of growth their size is smaller than 2 µm. Microscopy analysis is time and resource intensive; alternatively, backscattering is an inexpensive option for detecting particle sizes of interest.}, language = {en} } @misc{CapitainLukebaUlberetal.2018, author = {Capitain, C. C. and Lukeba, L. and Ulber, Roland and Tippk{\"o}tter, Nils}, title = {Biomimetische Klebstoffe aus Organosolv-Lignin}, series = {Chemie Ingenieur Technik}, volume = {90}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201855076}, pages = {1167}, year = {2018}, abstract = {Aufgrund von EU-Regularien und Umweltinitiativen w{\"a}chst der Markt f{\"u}r nachhaltige und abbaubare Klebstoffe stetig. Organosolv (OS)-Lignin ist ein kommerziell wenig ertragreicher Nebenstrom der Lignocellulose-Bioraffinerie. Durch das "Nachahmen" der Adh{\"a}sionseigenschaften mit strukturverwandten Muschel-Aminos{\"a}uren soll OS-Lignin in einen starkes, vollst{\"a}ndig biobasiertes Adh{\"a}siv umgewandelt werden. Funktionsweisend f{\"u}r die Adh{\"a}sion des Muschelklebstoffes ist die Catecholgruppe der Aminos{\"a}ure L-DOPA. Die laccase-katalysierte Polymerisationsreaktion von Lignin und L-DOPA ist schwierig zu kontrollieren, da L-DOPA eine Ringschlussreaktion eingeht. Stattdessen wurde eine zweistufige Reaktion mit einem Diamin als Ankermolek{\"u}l etabliert. Die Catecholgruppe, die im zweiten Schritt enzymatisch an das Lignin-Amin gebunden wird, kann durch Komplexbildung mit Fe(III)-Ionen sowohl zur Adh{\"a}sion als auch zur Koh{\"a}sion des Klebstoffes beitragen. Der Lignin-Catechol-Klebstoff ist frei von petrochemischen Chemikalien und biologisch abbaubar. In ersten Stirnzugversuchen konnte eine Haftkraft von 0,3 MPa erreicht werden.}, language = {de} } @misc{EngelBayerUlberetal.2018, author = {Engel, M. and Bayer, H. and Ulber, Roland and Tippk{\"o}tter, Nils}, title = {Kommt es in Elektrofermentationen mit Clostridium acetobutylicum zu einer Eisenlimitierung?}, series = {Chemie Ingenieur Technik}, volume = {90}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201855047}, pages = {1154}, year = {2018}, abstract = {Das strikt anaerobe Bakterium Clostridium acetobutylicum bildet die L{\"o}semittel Aceton, Butanol und Ethanol (ABE-Fermentation). Im Fall einer Eisenlimitierung kommt es zus{\"a}tzlich zu einer Riboflavinsekretion (RF), was durch die gelbe F{\"a}rbung des Kultur{\"u}berstands erkennbar ist. In dieser Arbeit wurde beobachtet, dass w{\"a}hrend Elektrofermentationen mit C. acetobutylicum bei -600 mV eine gelbe F{\"a}rbung 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 Eisenverf{\"u}gbarkeit hingegen wurden in den Serumflaschen fast keine Flavine sekretiert. Im BES bei -600 mV hingegen wurde auch in diesen Kultur{\"u}berst{\"a}nden 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 f{\"u}r eine m{\"o}gliche Flavinbildung werden aktuell n{\"a}her betrachtet.}, language = {de} } @misc{TippkoetterRothMoehringetal.2014, author = {Tippk{\"o}tter, Nils and Roth, J. and M{\"o}hring, M. and Wulfhorst, H. and Ulber, Roland}, title = {Verwertung von Bioraffinerie-Stoffstr{\"o}men am Beispiel von Einzellerproteinen}, series = {Chemie Ingenieur Technik}, volume = {86}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201450257}, pages = {1399 -- 1400}, year = {2014}, abstract = {Die Nutzung von Biomasse aus pflanzlichen Abf{\"a}llen f{\"u}r die stoffliche Verwertung r{\"u}ckt immer st{\"a}rker in den Vordergrund. Dabei ist vor allem die ganzheitliche Verwertung der Stoffstr{\"o}me von Bedeutung, da diese einen integrativen Ansatz erm{\"o}glichen. Im Rahmen dieser Arbeit wird die Produktion von Einzellerproteinen (Single-Cell Proteins, SCPs) mithilfe von unterschiedlichen Rohsubstraten dargelegt. Somit k{\"o}nnen Reststoffstr{\"o}me, die in keiner Konkurrenz zur Produktion von Lebensmitteln stehen, f{\"u}r die Herstellung von Futter- und auch Nahrungsmitteln Verwendung finden. Die zun{\"a}chst thermisch vorbehandelten Ausgangsmaterialien stammen aus forstwirtschaftlichen und gr{\"u}nen Abf{\"a}llen und erm{\"o}glichen durch eine anschließende enzymatische Hydrolyse die Freisetzung von Monosacchariden. Aus diesen erfolgt die SCP-Produktion fermentativ mithilfe der drei Modellorganismen Bakterium, Hefe und Pilz. Hierf{\"u}r wird sowohl das fl{\"u}ssige Hydrolysat als auch der feste Reststoff auf der Basis einer Feststofffermentation genutzt. Auf diese Weise ist eine vollst{\"a}ndige Verwertung der Ausgangsmaterialien m{\"o}glich. Mit den gewonnen Daten erfolgt abschließend eine Bewertung der SCPs aus nachwachsenden Rohstoffen als alternative Proteinquelle.}, language = {de} } @misc{TippkoetterPasteurMeyeretal.2012, author = {Tippk{\"o}tter, Nils and Pasteur, A. and Meyer, C. and Kampeis, P. and Diller, R. and Ulber, Roland}, title = {Aufreinigung von Cephalosporin C durch por{\"o}se, selektiv-beschichtete Magnetpartikel}, series = {Chemie Ingenieur Technik}, volume = {84}, journal = {Chemie Ingenieur Technik}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201250391}, pages = {1369 -- 1370}, year = {2012}, abstract = {Die selektive Isolierung von Cephalosporin C (CPC) aus komplexen Fermentationssuspensionen unter Einsatz magnetischer Separation ist das Ziel dieser Arbeit. Das Verfahren wird im fr{\"u}hen Stadium der Aufarbeitung genutzt, um CPC zu stabilisieren und somit die Produktausbeute zu erh{\"o}hen. Als Adsorbersysteme f{\"u}r CPC wurden neben einem projektinternen magnetischen Material ND 10322, dessen Oberfl{\"a}chenladungen spezifisch f{\"u}r die Bindung des Zielmolek{\"u}ls synthetisiert wurden, verschiedene kommerzielle Partikelsysteme verglichen. Es konnten massenspezifische Maximalbeladungen von 51 mg g⁻¹ erreicht werden. Weiterhin wurde die Stabilit{\"a}t von CPC untersucht. Unter optimalen Adsorptionsbedingungen kann CPC stabilisiert werden, so dass die Geschwindigkeitskonstante der Degradation des b-Lactam-Rings unter diesen Bedingungen unter 0,005 h⁻¹ liegt. Untersuchungen zur Wiederverwertbarkeit der neuen Adsorbers zeigten eine irreversible Bindung geringer CPC-Mengen nach dem ersten Einsatz. Nach zw{\"o}lf Zyklen tritt eine irreversible Bindung von CPC ein, was zu einer signifikanten Reduktion der Adsorptionsf{\"a}higkeit f{\"u}hrt. Die Anh{\"a}ufung des CPC auf dem Adsorber konnte durch IR-Untersuchungen auf die Bildung einer Peptidbindung zwischen Carboxylgruppen des CPC und Aminogruppe der Adsorberoberfl{\"a}che zur{\"u}ckgef{\"u}hrt werden.}, language = {de} } @misc{SiekerTippkoetterMuffleretal.2012, author = {Sieker, T. and Tippk{\"o}tter, Nils and Muffler, K. and Ulber, Roland}, title = {Herstellung von Ethanol, Phenols{\"a}uren, organischen S{\"a}uren und Biogas durch vollst{\"a}ndige Nutzung von Grassilage in einer Bioraffinerie}, series = {Chemie Ingenieur Technik}, volume = {84}, journal = {Chemie Ingenieur Technik}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.201250415}, pages = {1297}, year = {2012}, 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 zustellen. Um eine ganzj{\"a}hrige Nutzung des Grases zu gew{\"a}hrleisten, muss eine stabile Lagerung des Grases erreicht werden, was z. B. durch Silieren m{\"o}glich ist. Die konservierende Wirkung der Silierung beruht auf der Bildung organischer S{\"a}uren. Um diese zu gewinnen, wird die Silage gepresst, die organischen S{\"a}uren {\"u}ber Fl{\"u}ssig/Fl{\"u}ssig-Extraktion aus dem Presssaft abgetrenntund mittels chromatographischer Methoden weiter aufgereinigt. Im pr{\"a}sentierten Konzept werden die im Presskuchen enthaltenen Lignocellulosen hydrolysiert und die erhaltenen Monosaccharide zu Ethanol fermentiert. Die Phenols{\"a}uren, die in Gr{\"a}sern die Rolle des Lignins {\"u}bernehmen, k{\"o}nnen simultan mit der Hydrolyse der Polysaccharide enzymatisch abgetrennt und als Nebenprodukt gewonnen werden. Die nach der Abtrennung des Ethanols verbleibenden Fermentationsreststoffe werden f{\"u}r die Herstellung von Biogas verwendet.}, language = {de} } @misc{PothMonzonTippkoetteretal.2009, author = {Poth, S. and Monzon, M. and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Fermentation von Hydrolysaten aus Lignocellulose}, series = {Chemie Ingenieur Technik}, volume = {81}, journal = {Chemie Ingenieur Technik}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.200950243}, pages = {1220}, year = {2009}, abstract = {Die {\"o}konomische Abh{\"a}ngigkeit von fossilen Brennstoffen und der klimatische Wandel durch die Nutzung dieser haben zu einer intensiven Suche nach erneuerbaren Rohstoffen f{\"u}r die Produktion von Chemikalien und Treibstoffen gef{\"u}hrt. Ein viel versprechender Rohstoff in diesem Zusammenhang sind Zucker, die mittels enzymatischer Hydrolyse aus Lignocellulose gewonnen werden k{\"o}nnen. Die Fermentation erfolgt mit Cellulose- bzw. Hemicellulose-Fraktionen, welche durch thermo-chemische Vorbehandlung von Holz gewonnen und anschließend enzymatisch hydrolysiert werden. Die in den Hydrolysaten enthaltenen Zuckermonomere dienen als Kohlenstoffquelle f{\"u}r die Produktion von Ethanol. Da sowohl Glucose als auch Xylose in den unterschiedlichen Fraktionen enthalten sind, wird zur Umsetzung dieser eine Co-Fermentation zweier Hefen durchgef{\"u}hrt. Im Rahmen der Optimierung dieser Fermentationen werden neben der Erg{\"a}nzung der Hydrolysate durch notwendige Salze auch Verfahrenweisen wie Fed-Batch-Fermentationen untersucht. Ein weiterer interessanter Ansatz, welcher in diesem Rahmen gepr{\"u}ft wird, ist die enzymatische Hydrolyse der Lignocellulose-Fraktionen und die simultane Fermentation der dabei entstehenden Zucker in einem Schritt. Des Weiteren wurde die Eignung der Hydrolysate f{\"u}r die Biomasseproduktion anderer Mikroorganismen wie Escherichia coli getestet.}, language = {de} } @misc{TippkoetterUlber2009, author = {Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Eine magnetische horizontale Wirbelschicht f{\"u}r die Durchmischung und R{\"u}ckhaltung von magnetisierbaren Mikropartikeln im Durchfluss}, series = {Chemie Ingenieur Technik}, volume = {81}, journal = {Chemie Ingenieur Technik}, number = {8}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0009-286X}, doi = {10.1002/cite.200950076}, pages = {1168}, year = {2009}, abstract = {Magnetisierbare Partikel als Tr{\"a}ger von Katalysatoren k{\"o}nnen durch Anlegen eines magnetisches Feldes einfach und schnell abgetrennt werden. Die Wiedergewinnung von wertvollen Enzymen unter geringem Energie- und Materialeinsatz der magnetischen Abtrennung er{\"o}ffnet einen Wettbewerbsvorteil f{\"u}r Produktionsprozesse. Die Abtrennung von magnetisierbaren Partikeln vom {\"U}berstand wird {\"u}blicherweise entweder durch Anlegen eines {\"a}ußeren Magnetfelds und der resultierenden Ablagerung der Partikel an den Reaktorw{\"a}nden oder durch Hochgradientenmagnetseparation (HGMS)durchgef{\"u}hrt. Beide Verfahren resultieren meist in der Bildung eines Filterkuchens aus Magnetpartikeln und den Feststoffen des Reaktionsmediums. Das magnetische horizontale Wirbelbett erm{\"o}glicht simultan eine kontinuierliche Reaktionsf{\"u}hrung und die R{\"u}ckhaltung der Partikel im Durchfluss. Die Partikelsuspension fließt durch einen Rohrreaktor, der in einem Magnetfeld mit wechselnden Feldgradienten eingebracht ist. Die {\"A}nderung des Magnetfeldgradienten erfolgt entgegen der Str{\"o}mungsrichtung der Reaktionsl{\"o}sung. Durch alternierende Feldmaxima an den beiden Seiten des Reaktors werden die magnetisierbaren Partikel zu dessen W{\"a}nden gezogen. Bei Umkehrung des Feldes wandern die Partikel an die gegen{\"u}berliegende Reaktorwand. Durch Wahl einer geeigneten Wechselfrequenz kann eine kontinuierliche Durchmischung und R{\"u}ckhaltung der Mikropartikel im durchstr{\"o}mten Rohr erreicht werden. Somit k{\"o}nnen Immobilisierungsreaktionen und Biotransformationen mit den Partikelsystemen im Durchfluss durchgef{\"u}hrt werden.}, language = {en} } @article{HafidiElHatkaSchmitzetal.2024, author = {Hafidi, Youssef and El Hatka, Hicham and Schmitz, Dominik and Krauss, Manuel and Pettrak, J{\"u}rgen and Biel, Markus and Ittobane, Najim}, title = {Sustainable soil additives for water and micronutrient supply: swelling and chelating properties of polyaspartic acid hydrogels utilizing newly developed crosslinkers}, series = {Gels}, volume = {10}, journal = {Gels}, number = {3}, publisher = {MDPI}, address = {Basel}, issn = {2310-2861}, doi = {10.3390/gels10030170}, pages = {Artikel 170}, year = {2024}, abstract = {Drought and water shortage are serious problems in many arid and semi-arid regions. This problem is getting worse and even continues in temperate climatic regions due to climate change. To address this problem, the use of biodegradable hydrogels is increasingly important for the application as water-retaining additives in soil. Furthermore, efficient (micro-)nutrient supply can be provided by the use of tailored hydrogels. Biodegradable polyaspartic acid (PASP) hydrogels with different available (1,6-hexamethylene diamine (HMD) and L-lysine (LYS)) and newly developed crosslinkers based on diesters of glycine (GLY) and (di-)ethylene glycol (DEG and EG, respectively) were synthesized and characterized using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) and regarding their swelling properties (kinetic, absorbency under load (AUL)) as well as biodegradability of PASP hydrogel. Copper (II) and zinc (II), respectively, were loaded as micronutrients in two different approaches: in situ with crosslinking and subsequent loading of prepared hydrogels. The results showed successful syntheses of di-glycine-ester-based crosslinkers. Hydrogels with good water-absorbing properties were formed. Moreover, the developed crosslinking agents in combination with the specific reaction conditions resulted in higher water absorbency with increased crosslinker content used in synthesis (10\% vs. 20\%). The prepared hydrogels are candidates for water-storing soil additives due to the biodegradability of PASP, which is shown in an exemple. The incorporation of Cu(II) and Zn(II) ions can provide these micronutrients for plant growth.}, language = {en} } @article{HoffstadtNikolauszKrafftetal.2024, author = {Hoffstadt, Kevin and Nikolausz, Marcell and Krafft, Simone and Bonatelli, Maria and Kumar, Vivekanantha and Harms, Hauke and Kuperjans, Isabel}, title = {Optimization of the ex situ biomethanation of hydrogen and carbon dioxide in a novel meandering plug flow reactor: start-up phase and flexible operation}, series = {Bioengineering}, volume = {11}, journal = {Bioengineering}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2306-5354}, doi = {10.3390/bioengineering11020165}, pages = {18 Seiten}, year = {2024}, language = {en} }