@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{EngelGemuendeHoltmannetal.2019, author = {Engel, Mareike and Gem{\"u}nde, Andre and Holtmann, Dirk and M{\"u}ller-Renno, Christine and Ziegler, Christiane and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Clostridium acetobutylicum's connecting world: cell appendage formation in bioelectrochemical systems}, series = {ChemElectroChem}, volume = {7}, journal = {ChemElectroChem}, number = {2}, publisher = {Wiley}, address = {Weinheim}, issn = {2196-0216}, doi = {10.1002/celc.201901656}, pages = {414 -- 420}, year = {2019}, abstract = {Bacterial cell appendix formation supports cell-cell interaction, cell adhesion and cell movement. Additionally, in bioelectrochemical systems (BES), cell appendages have been shown to participate in extracellular electron transfer. In this work, the cell appendix formation of Clostridium acetobutylicum in biofilms of a BES are imaged and compared with conventional biofilms. Under all observed conditions, the cells possess filamentous appendages with a higher number and density in the BES. Differences in the amount of extracellular polymeric substance in the biofilms of the electrodes lead to the conclusion that the cathode can be used as electron donor and the anode as electron acceptor by C. acetobutylicum. When using conductive atomic force microscopy, a current response of about 15 nA is found for the cell appendages from the BES. This is the first report of conductivity for clostridial cell appendices and represents the basis for further studies on their role for biofilm formation and electron transfer.}, language = {en} } @article{TippkoetterRoikaewUlberetal.2010, author = {Tippk{\"o}tter, Nils and Roikaew, Wipa and Ulber, Roland and Hoffmann, Alexander and Denzler, Hans-J{\"o}rg and Buchholz, Heinrich}, title = {Paracoccus denitrificans for the effluent recycling during continuous denitrification of liquid food}, series = {Biotechnology Progress}, volume = {26}, journal = {Biotechnology Progress}, number = {3}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {8756-7938}, doi = {10.1002/btpr.384}, pages = {756 -- 762}, year = {2010}, abstract = {Nitrate is an undesirable component of several foods. A typical case of contamination with high nitrate contents is whey concentrate, containing nitrate in concentrations up to 25 l. The microbiological removal of nitrate by Paracoccus denitrificans under formation of harmless nitrogen in combination with a cell retention reactor is described here. Focus lies on the resource-conserving design of a microbal denitrification process. Two methods are compared. The application of polyvinyl alcohol-immobilized cells, which can be applied several times in whey feed, is compared with the implementation of a two step denitrification system. First, the whey concentrate's nitrate is removed by ion exchange and subsequently the eluent regenerated by microorganisms under their retention by crossflow filtration. Nitrite and nitrate concentrations were determined by reflectometric color measurement with a commercially available Reflectoquant® device. Correction factors for these media had to be determined. During the pilot development, bioreactors from 4 to 250 mg·L-1 and crossflow units with membrane areas from 0.02 to 0.80 m2 were examined. Based on the results of the pilot plants, a scaling for the exemplary process of denitrifying 1,000 tons per day is discussed.}, language = {en} } @incollection{DuweTippkoetterUlber2018, author = {Duwe, A. and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Lignocellulose-Biorefinery: Ethanol-Focused}, series = {Biorefineries}, booktitle = {Biorefineries}, publisher = {Springer}, address = {Cham}, doi = {10.1007/10_2016_72}, pages = {177 -- 215}, year = {2018}, abstract = {The development prospects of the world markets for petroleum and other liquid fuels are diverse and partly contradictory. However, comprehensive changes for the energy supply of the future are essential. Notwithstanding the fact that there are still very large deposits of energy resources from a geological point of view, the finite nature of conventional oil reserves is indisputable. To reduce our dependence on oil, the EU, the USA, and other major economic zones rely on energy diversification. For this purpose, alternative materials and technologies are being sought, and is most obvious in the transport sector. The objective is to progressively replace fossil fuels with renewable and more sustainable fuels. In this respect, biofuels have a pre-eminent position in terms of their capability of blending with fossil fuels and being usable in existing cars without substantial modification. Ethanol can be considered as the primary renewable liquid fuel. In this chapter enzymes, micro-organisms, and processes for ethanol production based on renewable resources are described.}, language = {en} } @article{SiekerUlberDimitrovaetal.2009, author = {Sieker, Tim and Ulber, Roland and Dimitrova, Darina and Bart, Hans-J{\"o}rg and Neuner, Andreas and Heinzle, Elmar and Tippk{\"o}tter, Nils}, title = {Silage : Fermentationsrohstoff f{\"u}r die chemische Industrie?}, series = {labor\&more}, journal = {labor\&more}, number = {2}, pages = {44 -- 45}, year = {2009}, abstract = {In Anbetracht des zu erwartenden R{\"u}ckgangs der Verf{\"u}gbarkeit fossiler Rohstoffe m{\"u}ssen nicht nur f{\"u}r den Energiesektor, sondern auch f{\"u}r die Herstellung industrieller Produkte alternative Rohstoffe gefunden werden. Ein Beispiel f{\"u}r einen nicht in Nahrungsmittelkonkurrenz stehenden nachwachsenden Rohstoff ist gr{\"u}ne Biomasse wie Gras und Klee. Diese lassen sich in Deutschland auf großen Fl{\"a}chen anbauen und enthalten eine Vielzahl potenzieller Substrate f{\"u}r Fermentationen.}, language = {de} } @misc{StadtmuellerTippkoetterUlber2015, author = {Stadtm{\"u}ller, Ralf and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Method for production of single-stranded macronucleotides}, year = {2015}, abstract = {The invention relates to a method for production of single-stranded macronucleotides by amplifying and ligating an extended monomeric single-stranded target nucleic acid sequence (targetss) into a repetitive cluster of double-stranded target nucleic acid sequences (targetds), and subsequently cloning the construct into a vector (aptagene vector). The aptagene vector is transformed into host cells for replication of the aptagene and isolated in order to optain single-stranded target sequences (targetss). The invention also relates to single-stranded nucleic acids, produced by a method of the invention.}, language = {en} } @article{TippkoetterStueckmannKrolletal.2009, author = {Tippk{\"o}tter, Nils and St{\"u}ckmann, Henning and Kroll, Stephen and Winkelmann, Gunda and Noack, Udo and Scheper, Thomas and Ulber, Roland}, title = {A semi-quantitative dipstick assay for microcystin}, series = {Analytical and Bioanalytical Chemistry}, volume = {394}, journal = {Analytical and Bioanalytical Chemistry}, number = {3}, publisher = {springer}, address = {Berlin}, issn = {1618-2650}, doi = {10.1007/s00216-009-2750-8}, pages = {863 -- 869}, year = {2009}, abstract = {An immunochromatographic lateral flow dipstick assay for the fast detection of microcystin-LR was developed. Colloid gold particles with diameters of 40 nm were used as red-colored antibody labels for the visual detection of the antigen. The new dipstick sensor is capable of detecting down to 5 µg·l-1 (ppb; total inversion of the color signal) or 1 ppb (observation of color grading) of microcystin-LR. The course of the labeling reaction was observed via spectrometric wave shifts caused by the change of particle size during the binding of antibodies. Different stabilizing reagents showed that especially bovine serum albumin (BSA) and casein increase the assays sensitivity and the conjugate stability. Performance of the dipsticks was quantified by pattern processing of capture zone CCD images. Storage stability of dipsticks and conjugate suspensions over 115 days under different conditions were monitored. The ready-to-use dipsticks were successfully tested with microcystin-LR-spiked samples of outdoor drinking- and salt water and applied to the tissue of microcystin-fed mussels.}, language = {en} } @inproceedings{HeringUlberTippkoetter2016, author = {Hering, T. and Ulber, Roland and Tippk{\"o}tter, Nils}, title = {Development of a screening system for antimicrobial surfaces}, series = {New frontiers of biotech-processes (Himmelfahrtstagung) : 02-04 May 2016, Rhein-Mosel-Halle, Koblenz/Germany}, booktitle = {New frontiers of biotech-processes (Himmelfahrtstagung) : 02-04 May 2016, Rhein-Mosel-Halle, Koblenz/Germany}, publisher = {DECHEMA}, address = {Frankfurt am Main}, pages = {129}, year = {2016}, language = {en} } @inproceedings{CapitainHeringTippkoetteretal.2016, author = {Capitain, C. and Hering, T. and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Enzymatic polymerization of lignin model compounds and solubilized lignin in an aqueous ethanol extract}, series = {New frontiers of biotech-processes (Himmelfahrtstagung) : 02-04 May 2016, Rhein-Mosel-Halle, Koblenz/Germany}, booktitle = {New frontiers of biotech-processes (Himmelfahrtstagung) : 02-04 May 2016, Rhein-Mosel-Halle, Koblenz/Germany}, publisher = {DECHEMA}, address = {Frankfurt am Main}, pages = {151 -- 152}, year = {2016}, language = {en} } @article{TippkoetterAlKaidyWollnyetal.2013, author = {Tippk{\"o}tter, Nils and Al-Kaidy, Huschyar and Wollny, Steffen and Ulber, Roland}, title = {Functionalized magnetizable particles for downstream processing in single-use systems}, series = {Chemie Ingenieur Technik}, volume = {85}, journal = {Chemie Ingenieur Technik}, number = {1-2: Special Issue: Single-Use Technology}, publisher = {Wiley}, address = {Weinheim}, doi = {10.1002/cite.201200130}, pages = {76 -- 86}, year = {2013}, abstract = {Biotechnological downstream processing is usually an elaborate procedure, requiring a multitude of unit operations to isolate the target component. Besides the disadvantageous space-time yield, the risks of cross-contaminations and product loss grow fast with the complexity of the isolation procedure. A significant reduction of unit operations can be achieved by application of magnetic particles, especially if these are functionalized with affinity ligands. As magnetic susceptible materials are highly uncommon in biotechnological processes, target binding and selective separation of such particles from fermentation or reactions broths can be done in a single step. Since the magnetizable particles can be produced from iron salts and low priced polymers, a single-use implementation of these systems is highly conceivable. In this article, the principles of magnetizable particles, their synthesis and functionalization are explained. Furthermore, applications in the area of reaction engineering, microfluidics and downstream processing are discussed focusing on established single-use technologies and development potential.}, language = {en} }