@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},
  journal   = {Biotechnology Journal},
  number    = {Volume 14, Issue 4},
  publisher = {Wiley-VCH},
  issn      = {1860-7314},
  doi       = {10.1002/biot.201800514},
  pages     = {Artikel 1800514},
  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},
  journal   = {ChemElectroChem},
  number    = {Accepted Article},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {2196-0216},
  doi       = {10.1002/celc.201901656},
  year      = {2019},
  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{EngelBayerHoltmannetal.2019,
  author    = {Engel, Mareike and Bayer, Hendrik and Holtmann, Dirk and Tippk{\"o}tter, Nils and Ulber, Roland},
  title     = {Flavin secretion of Clostridium acetobutylicum in a bioelectrochemical system - Is an iron limitation involved?},
  series = {Bioelectrochemistry},
  journal   = {Bioelectrochemistry},
  number    = {In Press, Accepted Manuscript},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1567-5394},
  doi       = {10.1016/j.bioelechem.2019.05.014},
  year      = {2019},
  language  = {en}
}
@article{CapitainWagnerHummeletal.2021,
  author    = {Capitain, Charlotte and Wagner, Sebastian and Hummel, Joana and Tippk{\"o}tter, Nils},
  title     = {Investigation of C-N Formation Between Catechols and Chitosan for the Formation of a Strong, Novel Adhesive Mimicking Mussel Adhesion},
  series = {Waste and Biomass Valorization},
  volume    = {12},
  journal   = {Waste and Biomass Valorization},
  publisher = {Springer Nature},
  address   = {Cham},
  issn      = {1877-265X},
  doi       = {10.1007/s12649-020-01110-5},
  pages     = {1761 -- 1779},
  year      = {2021},
  language  = {en}
}
@article{CapitainRossJonesMoehringetal.2020,
  author    = {Capitain, Charlotte and Ross-Jones, Jesse and M{\"o}hring, Sophie and Tippk{\"o}tter, Nils},
  title     = {Differential scanning calorimetry for quantification of polymer biodegradability in compost},
  series = {International Biodeterioration \& Biodegradation},
  volume    = {149},
  journal   = {International Biodeterioration \& Biodegradation},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0964-8305},
  doi       = {10.1016/j.ibiod.2020.104914},
  pages     = {In Press, Article number 104914},
  year      = {2020},
  abstract  = {The objective of this study is the establishment of a differential scanning calorimetry (DSC) based method for online analysis of the biodegradation of polymers in complex environments. Structural changes during biodegradation, such as an increase in brittleness or crystallinity, can be detected by carefully observing characteristic changes in DSC profiles. Until now, DSC profiles have not been used to draw quantitative conclusions about biodegradation. A new method is presented for quantifying the biodegradation using DSC data, whereby the results were validated using two reference methods. The proposed method is applied to evaluate the biodegradation of three polymeric biomaterials: polyhydroxybutyrate (PHB), cellulose acetate (CA) and Organosolv lignin. The method is suitable for the precise quantification of the biodegradability of PHB. For CA and lignin, conclusions regarding their biodegradation can be drawn with lower resolutions. The proposed method is also able to quantify the biodegradation of blends or composite materials, which differentiates it from commonly used degradation detection methods.},
  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}
}
@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{SiekerNeunerDimitrovaetal.2010,
  author    = {Sieker, Tim and Neuner, Andreas and Dimitrova, Darina and Tippk{\"o}tter, Nils and Bart, Hans-J{\"o}rg and Heinzle, Elmar and Ulber, Roland},
  title     = {Grassilage als Rohstoff f{\"u}r die chemische Industrie},
  series = {Chemie Ingenieur Technik},
  volume    = {82},
  journal   = {Chemie Ingenieur Technik},
  number    = {8, Special Issue: Industrielle Nutzung nachwachsender Rohstoffe},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1522-2640},
  doi       = {10.1002/cite.201000088},
  pages     = {1153 -- 1159},
  year      = {2010},
  abstract  = {Grassilage stellt einen nachwachsenden Rohstoff mit großem Potenzial dar. Neben Cellulose und Hemicellulose enth{\"a}lt sie auch organische S{\"a}uren, insbesondere Milchs{\"a}ure. In einem Bioraffinerie-Projekt wird die Milchs{\"a}ure aus der Silage isoliert und mit gentechnisch optimierten St{\"a}mmen zu L-Lysin weiterverarbeitet. Die Lignocellulose wird hydrolysiert und zu Ethanol fermentiert. Ein besonderes Augenmerk liegt auf der Integration der unterschiedlichen Prozesse sowie der einzelnen Prozessschritte zu einem Gesamtprozess, der s{\"a}mtliche Inhaltsstoffe der Silage verwertet.},
  language  = {de}
}