@article{AlKaidyTippkoetter2016,
  author    = {Al-Kaidy, Huschyar and Tippk{\"o}tter, Nils},
  title     = {Superparamagnetic hydrophobic particles as shell material for digital microfluidic droplets and proof-of-principle reaction assessments with immobilized laccase},
  series = {Engineering in Life Sciences},
  volume    = {16},
  journal   = {Engineering in Life Sciences},
  number    = {3},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  doi       = {10.1002/elsc.201400124},
  pages     = {222 -- 230},
  year      = {2016},
  abstract  = {In the field of biotechnology and molecular biology, the use of small liquid volumes has significant advantages. In particular, screening and optimization runs with acceptable amounts of expensive and hardly available catalysts, reagents, or biomolecules are feasible with microfluidic technologies. The presented new microfluidic system is based on the inclusion of small liquid volumes by a protective shell of magnetizable microparticles. Hereby, discrete aqueous microreactor drops with volumes of 1-30 μL can be formed on a simple planar surface. A digital movement and manipulation of the microreactor is performed by overlapping magnetic forces. The magnetic forces are generated by an electrical coil matrix positioned below a glass plate. With the new platform technology, several discrete reaction compartments can be moved simultaneously on one surface. Due to the magnetic fields, the reactors can even be merged to initiate reactions by mixing or positioned above surface-immobilized catalysts and then opened by magnetic force. Comparative synthesis routes of the magnetizable shell particles and superhydrophobic glass slides including their performance and stability with the reaction platform are described. The influence of diffusive mass transport during the catalyzed reaction is discussed by evaluation finite element model of the microreactor. Furthermore, a first model dye reaction of the enzyme laccase has been established.},
  language  = {en}
}
@article{SchumannRoginSchneideretal.2015,
  author    = {Schumann, Christiane and Rogin, Sabine and Schneider, Horst and Tippk{\"o}tter, Nils and Oster, J{\"u}rgen and Kampeis, Percy},
  title     = {Simultane Atline-Quantifizierung von Magnetpartikeln und Mikroorganismen bei einer HGMS-Filtration},
  series = {Chemie Ingenieur Technik},
  volume    = {87},
  journal   = {Chemie Ingenieur Technik},
  number    = {1-2},
  doi       = {10.1002/cite.201300158},
  pages     = {137 -- 149},
  year      = {2015},
  abstract  = {Es wird eine neue Atline-Messmethode vorgestellt, mit der w{\"a}hrend einer Hochgradienten-Magnetseparation (HGMS)-Filtration eine simultane Quantifizierung von Magnetpartikeln und Mikroorganismen im Filtrat vorgenommen werden kann. Dabei gelingt die Quantifizierung signifikant besser als mit bisher verwendeten Messmethoden. Mit dieser Methode ist es m{\"o}glich, die Trennleistung einer HGMS-Filtration zu bestimmen und einen Filterdurchbruch durch Konzentrationsanstiege im Bereich einiger µg L-1 von Magnetpartikeln im Filtrat fr{\"u}hzeitig zu detektieren, ohne dass nennenswerte Partikelmengen verloren gehen.},
  language  = {de}
}
@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}
}
@article{TippkoetterWollnySucketal.2014,
  author    = {Tippk{\"o}tter, Nils and Wollny, Steffen and Suck, Kirstin and Sohling, Ulrich and Ruf, Friedrich and Ulber, Roland},
  title     = {Recycling of spent oil bleaching earth as source of glycerol for the anaerobic production of acetone, butanol, and ethanol with Clostridium diolis and lipolytic Clostridium lundense},
  series = {Engineering in Life Sciences},
  volume    = {14},
  journal   = {Engineering in Life Sciences},
  number    = {4},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1618-2863},
  doi       = {10.1002/elsc.201300113},
  pages     = {425 -- 432},
  year      = {2014},
  abstract  = {A major part of edible oil is subjected to bleaching procedures, primarily with minerals applied as adsorbers. Their recycling is currently done either by regaining the oil via organic solvent extraction or by using the spent bleaching earth (SBE) as additive for animal feed, etc. As a new method, the reutilization of the by-product SBE for the microbiologic formation of acetone, butanol, and ethanol (ABE) is presented as proof-of-concept. The SBE was taken from a palm oil cleaning process. The recycling concept is based on the application of lipolytic clostridia strains. Due to considerably long fermentation times, co-fermentation with Candida rugosa and enzymatic hydrolyses of the bound oil with a subsequent clostridia fermentation are shown as alternative routes. Anaerobic fermentations under comparison of different clostridia strains were performed with glycerol media, enzymatically hydrolyzed palm oil and SBE. Solutes, side product compositions and productivities were quantified via HPLC. A successful production of ABE solutes from SBE has been done with a yield of 0.15 g butanol per gram of bound glycerol. Thus, the biotechnological recycling of the waste stream is possible in principle. Inhibition of the substrate suspension has been observed. A chromatographic ion-exchange of substrates increased the biomass concentration.},
  language  = {en}
}
@article{TippkoetterRoth2020,
  author    = {Tippk{\"o}tter, Nils and Roth, Jasmine},
  title     = {Purified Butanol from Lignocellulose - Solvent-Impregnated Resins for an Integrated Selective Removal},
  series = {Chemie Ingenieur Technik},
  volume    = {92},
  journal   = {Chemie Ingenieur Technik},
  number    = {11},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1522-2640},
  doi       = {10.1002/cite.202000200},
  pages     = {1741 -- 1751},
  year      = {2020},
  abstract  = {In traditional microbial biobutanol production, the solvent must be recovered during fermentation process for a sufficient space-time yield. Thermal separation is not feasible due to the boiling point of n-butanol. As an integrated and selective solid-liquid separation alternative, solvent impregnated resins (SIRs) were applied. Two polymeric resins were evaluated and an extractant screening was conducted. Vacuum application with vapor collection in fixed-bed column as bioreactor bypass was successfully implemented as butanol desorption step. In course of further increasing process economics, fermentation with renewable lignocellulosic substrates was conducted using Clostridium acetobutylicum. Utilization of SIR was shown to be a potential strategy for solvent removal from fermentation broth, while application of a bypass column allows for product removal and recovery at once.},
  language  = {en}
}
@article{UlberPothMonzonetal.2010,
  author    = {Ulber, Roland and Poth, Sebastian and Monzon, Magaly and Tippk{\"o}tter, Nils},
  title     = {Prozessintegration von Hydrolyse und Fermentation von Cellulose- Faserstoff},
  series = {Chemie Ingenieur Technik},
  volume    = {82},
  journal   = {Chemie Ingenieur Technik},
  number    = {1-2},
  issn      = {1522-2640},
  doi       = {10.1002/cite.200900103},
  pages     = {135 -- 139},
  year      = {2010},
  abstract  = {Ein viel versprechender erneuerbarer Rohstoff f{\"u}r die Produktion von Chemikalien und Treibstoffen ist Lignocellulose aus pflanzlicher Biomasse. Die darin enthaltenen Zucker k{\"o}nnen mittels enzymatischer Hydrolyse freigesetzt und fermentativ zu Ethanol umgesetzt werden. Ein interessanter Ansatz ist dabei die simultane Verzuckerung und Fermentation. Hefen und Enzyme haben mit 30 °C bzw. 50 °C zwar unterschiedliche Temperaturoptima, es konnte aber gezeigt werden, dass auch bei den niedrigeren Temperaturen eine Umsetzung der Cellulose zu Glucose erfolgt, wenn auch langsamer als bei optimalen Bedingungen. Außerdem konnte in Vorversuchen gezeigt werden, dass Ethanol in den zu erwartenden Konzentrationen keinen Einfluss auf die enzymatische Umsetzung hat.},
  language  = {de}
}
@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}
}
@article{PasteurTippkoetterKampeisetal.2014,
  author    = {Pasteur, Aline and Tippk{\"o}tter, Nils and Kampeis, Percy and Ulber, Roland},
  title     = {Optimization of high gradient magnetic separation filter units for the purification of fermentation products},
  series = {IEEE TRANSACTIONS ON MAGNETICS},
  volume    = {50},
  journal   = {IEEE TRANSACTIONS ON MAGNETICS},
  number    = {10},
  publisher = {IEEE},
  address   = {New York, NY},
  issn      = {0018-9464},
  doi       = {10.1109/TMAG.2014.2325535},
  pages     = {Artikel 5000607},
  year      = {2014},
  abstract  = {High gradient magnetic separation (HGMS) has been established since the early 1970s. A more recent application of these systems is the use in bioprocesses. To integrate the HGMS in a fermentation process, it is necessary to optimize the separation matrix with regard to the magnetic separation characteristics and permeability of the non-magnetizable components of the fermentation broth. As part of the work presented here, a combined fluidic and magnetic force finite element model simulation was created using the software COMSOL Multiphysics and compared with separation experiments. Finally, as optimal lattice orientation of the separation matrix, a transversal rhombohedral arrangement was defined. The high suitability of the new filter matrix has been verified by separation experiments.},
  language  = {en}
}
@article{UlberTippkoetter2009,
  author    = {Ulber, Roland and Tippk{\"o}tter, Nils},
  title     = {Nitratfreie Molke},
  series = {Rundschau f{\"u}r Fleischhygiene und Lebensmittel{\"u}berwachung},
  journal   = {Rundschau f{\"u}r Fleischhygiene und Lebensmittel{\"u}berwachung},
  number    = {4},
  pages     = {150 -- 152},
  year      = {2009},
  language  = {de}
}
@article{TippkoetterRoikaewUlber2007,
  author    = {Tippk{\"o}tter, Nils and Roikaew, N. and Ulber, R.},
  title     = {Nitratentfernung aus Molkekonzentrat mit biotechnologischer Regeneration der Abw{\"a}sser},
  series = {Deutsche Milchwirtschaft},
  volume    = {58},
  journal   = {Deutsche Milchwirtschaft},
  number    = {15},
  issn      = {0012-0480},
  pages     = {540 -- 542},
  year      = {2007},
  language  = {de}
}