@article{SchiffelsSelmer2019,
  author    = {Schiffels, Johannes and Selmer, Thorsten},
  title     = {Combinatorial assembly of ferredoxin-linked modules in Escherichia coli yields a testing platform for Rnf-complexes},
  series = {Biotechnology and Bioengineering},
  journal   = {Biotechnology and Bioengineering},
  number    = {accepted article},
  publisher = {Wiley},
  address   = {Weinheim},
  doi       = {10.1002/bit.27079},
  pages     = {1 -- 36},
  year      = {2019},
  language  = {en}
}
@article{HentschkeHagerHojdis2014,
  author    = {Hentschke, Reinhard and Hager, Jonathan and Hojdis, Nils},
  title     = {Molecular Modeling Approach to the Prediction of Mechanical Properties of Silica-Reinforced Rubbers},
  series = {Journal of Applied Polymer Science},
  volume    = {131},
  journal   = {Journal of Applied Polymer Science},
  number    = {18},
  publisher = {Wiley},
  address   = {New York, NY},
  issn      = {1097-4628},
  doi       = {10.1002/app.40806},
  pages     = {1 -- 9},
  year      = {2014},
  abstract  = {Recently, we have suggested a nanomechanical model for dissipative loss in filled elastomer networks in the context of the Payne effect. The mechanism is based on a total interfiller particle force exhibiting an intermittent loop, due to the combination of short-range repulsion and dispersion forces with a long-range elastic attraction. The sum of these forces leads, under external strain, to a spontaneous instability of "bonds" between the aggregates in a filler network and attendant energy dissipation. Here, we use molecular dynamics simulations to obtain chemically realistic forces between surface modified silica particles. The latter are combined with the above model to estimate the loss modulus and the low strain storage modulus in elastomers containing the aforementioned filler-compatibilizer systems. The model is compared to experimental dynamic moduli of silica filled rubbers. We find good agreement between the model predictions and the experiments as function of the compatibilizer's molecular structure and its bulk concentration.},
  language  = {en}
}
@article{VoigtSchroeterJuergenetal.2013,
  author    = {Voigt, Birgit and Schroeter, Rebecca and J{\"u}rgen, Britta and Albrecht, Dirk and Evers, Stefan and Bongaerts, Johannes and Maurer, Karl-Heinz and Schweder, Thomas and Hecker, Michael},
  title     = {The response of Bacillus licheniformis to heat and ethanol stress and the role of the SigB regulon},
  series = {Proteomics},
  volume    = {Vol. 13},
  journal   = {Proteomics},
  number    = {Iss. 14},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1615-9861 (E-Journal); 1615-9853 (Print)},
  pages     = {2140 -- 2146},
  year      = {2013},
  language  = {en}
}
@article{FalkenbergRahbaFischeretal.2022,
  author    = {Falkenberg, Fabian and Rahba, Jade and Fischer, David and Bott, Michael and Bongaerts, Johannes and Siegert, Petra},
  title     = {Biochemical characterization of a novel oxidatively stable, halotolerant, and high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101T},
  series = {FEBS Open Bio},
  volume    = {12},
  journal   = {FEBS Open Bio},
  number    = {10},
  publisher = {Wiley},
  address   = {Hoboken, NJ},
  issn      = {2211-5463},
  doi       = {10.1002/2211-5463.13457},
  pages     = {1729 -- 1746},
  year      = {2022},
  abstract  = {Halophilic and halotolerant microorganisms represent a promising source of salt-tolerant enzymes suitable for various biotechnological applications where high salt concentrations would otherwise limit enzymatic activity. Considering the current growing enzyme market and the need for more efficient and new biocatalysts, the present study aimed at the characterization of a high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101T. The protease gene was cloned and expressed in Bacillus subtilis DB104. The recombinant protease SPAO with 269 amino acids belongs to the subfamily of high-alkaline subtilisins. The biochemical characteristics of purified SPAO were analyzed in comparison with subtilisin Carlsberg, Savinase, and BPN'. SPAO, a monomer with a molecular mass of 27.1 kDa, was active over a wide range of pH 6.0-12.0 and temperature 20-80 °C, optimally at pH 9.0-9.5 and 55 °C. The protease is highly oxidatively stable to hydrogen peroxide and retained 58\% of residual activity when incubated at 10 °C with 5\% (v/v) H2O2 for 1 h while stimulated at 1\% (v/v) H2O2. Furthermore, SPAO was very stable and active at NaCl concentrations up to 5.0 m. This study demonstrates the potential of SPAO for biotechnological applications in the future.},
  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{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}
}
@article{ThielTippkoetterSucketal.2013,
  author    = {Thiel, Alexander and Tippk{\"o}tter, Nils and Suck, Kirstin and Sohling, Ulrich and Ruf, Friedrich and Ulber, Roland},
  title     = {New zeolite adsorbents for downstream processing of polyphenols from renewable resources},
  series = {Engineering in Life Sciences},
  volume    = {13},
  journal   = {Engineering in Life Sciences},
  number    = {3},
  publisher = {Wiley},
  address   = {Weinheim},
  doi       = {10.1002/elsc.201200188},
  pages     = {239 -- 246},
  year      = {2013},
  abstract  = {Commercial materials with polyvinylpolypyrrolidone and polymeric amberlites (XAD7HP, XAD16) are commonly used for the adsorptive downstream processing of polyphenols from renewable resources. In this study, beta-zeolite-based adsorbent systems were examined, and their properties were compared to organic resins. Batch adsorption experiments were conducted with synthetic solutions of major polyphenols. Adsorption isotherms and desorption characteristics of individual adsorbent were determined based on these results. Maximum adsorption capacities were calculated using the Langmuir model. For example, the zeolites had capacities up to 203.2 mg/g for ferulic acid. To extend these results to a complex system, additional experiments were performed on rapeseed meal and wheat seed extracts as representative renewable resources. HPLC analysis showed that with 7.5\% w/v, which is regarded as the optimum amount of zeolites, zeolites A and B could bind 100\% of the major polyphenols as well as release polyphenols at high yields. Additionally, regeneration experiments were performed with isopropyl alcohol at 99°C to evaluate how zeolites regenerate under mild conditions. The results showed only a negligible loss of adsorption capacity and no loss of desorption capacity. In summary, it was concluded that beta-zeolites were promising adsorbents for developing new processes to isolate polyphenols from renewable resources.},
  language  = {en}
}
@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{ThielMufflerTippkoetteretal.2015,
  author    = {Thiel, Alexander and Muffler, Kai and Tippk{\"o}tter, Nils and Suck, Kirstin and Sohling, Ulrich and Ruf, Friedrich and Ulber, Roland},
  title     = {Aufarbeitung von Polyphenolen aus Weizen mittels Zeolithen am Beispiel der Ferulas{\"a}ure},
  series = {Chemie IngenieurTechnik},
  volume    = {87},
  journal   = {Chemie IngenieurTechnik},
  number    = {1-2},
  publisher = {Wiley},
  address   = {Weinheim},
  doi       = {10.1002/cite.201400031},
  pages     = {128 -- 136},
  year      = {2015},
  abstract  = {Aufarbeitung von Polyphenolen aus Weizenmittels Zeolithen am Beispiel der Ferulasa¨ ureAlexander Thiel1, Kai Muffler1, Nils Tippko¨ tter1, Kirstin Suck2, Ulrich Sohling2, Friedrich Ruf3und Roland Ulber1,*DOI: 10.1002/cite.201400031Bei der Ferulasa¨ure handelt es sich um einen Wertstoff, der aus Weizen gewonnen und in der Lebensmittel- und Pharma-industrie eingesetzt werden kann. Der Einsatz von Weizen als nachwachsende Rohstoffquelle ist allerdings nur dann wirt-schaftlich durchfu¨hrbar, wenn eine Prozessintegration in die bestehenden industriellen Verfahren gewa¨hrleistet oder einedirekte Konkurrenz zur Mehl- und Sta¨rkeindustrie vermieden werden kann. In diesem Artikel wird ein Verfahren aufge-zeigt, welches hohe Ausbeuten ermo¨glicht und eine Konkurrenz zu bestehenden Verwertungspfaden vermeidet.},
  language  = {de}
}
@article{AlKaidyDuweHusteretal.2015,
  author    = {Al-Kaidy, Huschyar and Duwe, Anna and Huster, Manuel and Muffler, Kai and Schlegel, Christin and Tim, Sieker and Stadtm{\"u}ller, Ralf and Tippk{\"o}tter, Nils and Ulber, Roland},
  title     = {Biotechnology and bioprocess engineering - from the first ullmann's article to recent trends},
  series = {ChemBioEng Reviews},
  volume    = {2},
  journal   = {ChemBioEng Reviews},
  number    = {3},
  publisher = {Wiley},
  address   = {Weinheim},
  doi       = {10.1002/cben.201500008},
  pages     = {175 -- 184},
  year      = {2015},
  abstract  = {For several thousand years, biotechnology and its associated technical processes have had a great impact on the development of mankind. Based on empirical methods, in particular for the production of foodstuffs and daily commodities, these disciplines have become one of the most innovative future issues. Due to the increasing detailed understanding of cellular processes, production strains can now be optimized. In combination with modern bioprocesses, a variety of bulk and fine chemicals as well as pharmaceuticals can be produced efficiently. In this article, some of the current trends in biotechnology are discussed.},
  language  = {en}
}
@article{TippkoetterWollnyKampeisetal.2011,
  author    = {Tippk{\"o}tter, Nils and Wollny, S. and Kampeis, P. and Oster, J. and Schneider, H. and Ulber, Roland},
  title     = {Magnetseparation von Proteinen : Separation von Zielmolek{\"u}len durch hochselektive Aptamere},
  series = {GIT Labor-Fachzeitschrift},
  volume    = {55},
  journal   = {GIT Labor-Fachzeitschrift},
  number    = {10},
  publisher = {Wiley},
  address   = {Weinheim},
  pages     = {666},
  year      = {2011},
  abstract  = {Durch die Kombination von Oligonukleotid-Liganden (Aptameren) hoher Bindungsaffinit{\"a}ten mit hochselektiv abtrennbaren magnetisierbaren Mikropartikeln wird eine einstufige Separation von Zielmolek{\"u}len aus mikrobiologischen Produktionsans{\"a}tzen m{\"o}glich. Die Aptamere werden hierf{\"u}r reversibel auf den Partikeloberfl{\"a}chen gebunden und f{\"u}r die spezifische Isolierung von Bioprodukten eingesetzt. Die Abtrennung der beladenen Partikel erfolgt durch einen neuen Rotor-Stator-Separator mit Hochgradient-Magnetfeld.},
  language  = {de}
}
@article{HaegerProbstJaegeretal.2023,
  author    = {Haeger, Gerrit and Probst, Johanna and Jaeger, Karl-Erich and Bongaerts, Johannes and Siegert, Petra},
  title     = {Novel aminoacylases from Streptomyces griseus DSM 40236 and their recombinant production in Streptomyces lividans},
  series = {FEBS Open Bio},
  volume    = {13},
  journal   = {FEBS Open Bio},
  number    = {12},
  publisher = {Wiley},
  address   = {Hoboken, NJ},
  issn      = {2211-5463},
  doi       = {10.1002/2211-5463.13723},
  pages     = {2224 -- 2238},
  year      = {2023},
  abstract  = {Amino acid-based surfactants are valuable compounds for cosmetic formulations. The chemical synthesis of acyl-amino acids is conventionally performed by the Schotten-Baumann reaction using fatty acyl chlorides, but aminoacylases have also been investigated for use in biocatalytic synthesis with free fatty acids. Aminoacylases and their properties are diverse; they belong to different peptidase families and show differences in substrate specificity and biocatalytic potential. Bacterial aminoacylases capable of synthesis have been isolated from Burkholderia, Mycolicibacterium, and Streptomyces. Although several proteases and peptidases from S. griseus have been described, no aminoacylases from this species have been identified yet. In this study, we investigated two novel enzymes produced by S. griseus DSM 40236ᵀ . We identified and cloned the respective genes and recombinantly expressed an α-aminoacylase (EC 3.5.1.14), designated SgAA, and an ε-lysine acylase (EC 3.5.1.17), designated SgELA, in S. lividans TK23. The purified aminoacylase SgAA was biochemically characterized, focusing on its hydrolytic activity to determine temperature- and pH optima and stabilities. The aminoacylase could hydrolyze various acetyl-amino acids at the Nα -position with a broad specificity regarding the sidechain. Substrates with longer acyl chains, like lauroyl-amino acids, were hydrolyzed to a lesser extent. Purified aminoacylase SgELA specific for the hydrolysis of Nε -acetyl-L-lysine was unstable and lost its enzymatic activity upon storage for a longer period but could initially be characterized. The pH optimum of SgELA was pH 8.0. While synthesis of acyl-amino acids was not observed with SgELA, SgAA catalyzed the synthesis of lauroyl-methionine.},
  language  = {en}
}