@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{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{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{EveraersKarimiVarzanehFlecketal.2020, author = {Everaers, Ralf and Karimi-Varzaneh, Hossein Ali and Fleck, Franz and Hojdis, Nils and Svaneborg, Carsten}, title = {Kremer-Grest Models for Commodity Polymer Melts: Linking Theory, Experiment, and Simulation at the Kuhn Scale}, series = {Macromolecules}, volume = {53}, journal = {Macromolecules}, number = {6}, publisher = {ACS Publications}, address = {Washington, DC}, issn = {1520-5835}, doi = {10.1021/acs.macromol.9b02428}, pages = {1901 -- 1916}, year = {2020}, abstract = {The Kremer-Grest (KG) polymer model is a standard model for studying generic polymer properties in molecular dynamics simulations. It owes its popularity to its simplicity and computational efficiency, rather than its ability to represent specific polymers species and conditions. Here we show that by tuning the chain stiffness it is possible to adapt the KG model to model melts of real polymers. In particular, we provide mapping relations from KG to SI units for a wide range of commodity polymers. The connection between the experimental and the KG melts is made at the Kuhn scale, i.e., at the crossover from the chemistry-specific small scale to the universal large scale behavior. We expect Kuhn scale-mapped KG models to faithfully represent universal properties dominated by the large scale conformational statistics and dynamics of flexible polymers. In particular, we observe very good agreement between entanglement moduli of our KG models and the experimental moduli of the target polymers.}, 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{FalkenbergKohnBottetal.2023, author = {Falkenberg, Fabian and Kohn, Sophie and Bott, Michael and Bongaerts, Johannes and Siegert, Petra}, title = {Biochemical characterisation of a novel broad pH spectrum subtilisin from Fictibacillus arsenicus DSM 15822ᵀ}, series = {FEBS Open Bio}, volume = {13}, journal = {FEBS Open Bio}, number = {11}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {2211-5463}, doi = {10.1002/2211-5463.13701}, pages = {2035 -- 2046}, year = {2023}, abstract = {Subtilisins from microbial sources, especially from the Bacillaceae family, are of particular interest for biotechnological applications and serve the currently growing enzyme market as efficient and novel biocatalysts. Biotechnological applications include use in detergents, cosmetics, leather processing, wastewater treatment and pharmaceuticals. To identify a possible candidate for the enzyme market, here we cloned the gene of the subtilisin SPFA from Fictibacillus arsenicus DSM 15822ᵀ (obtained through a data mining-based search) and expressed it in Bacillus subtilis DB104. After production and purification, the protease showed a molecular mass of 27.57 kDa and a pI of 5.8. SPFA displayed hydrolytic activity at a temperature optimum of 80 °C and a very broad pH optimum between 8.5 and 11.5, with high activity up to pH 12.5. SPFA displayed no NaCl dependence but a high NaCl tolerance, with decreasing activity up to concentrations of 5 m NaCl. The stability enhanced with increasing NaCl concentration. Based on its substrate preference for 10 synthetic peptide 4-nitroanilide substrates with three or four amino acids and its phylogenetic classification, SPFA can be assigned to the subgroup of true subtilisins. Moreover, SPFA exhibited high tolerance to 5\% (w/v) SDS and 5\% H₂O₂ (v/v). The biochemical properties of SPFA, especially its tolerance of remarkably high pH, SDS and H₂O₂, suggest it has potential for biotechnological applications.}, 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{FalkenbergVossBottetal.2023, author = {Falkenberg, Fabian and Voß, Leonie and Bott, Michael and Bongaerts, Johannes and Siegert, Petra}, title = {New robust subtilisins from halotolerant and halophilic Bacillaceae}, series = {Applied Microbiology and Biotechnology}, volume = {107}, journal = {Applied Microbiology and Biotechnology}, publisher = {Springer Nature}, address = {Berlin}, issn = {1432-0614}, doi = {10.1007/s00253-023-12553-w}, pages = {3939 -- 3954}, year = {2023}, abstract = {The aim of the present study was the characterisation of three true subtilisins and one phylogenetically intermediate subtilisin from halotolerant and halophilic microorganisms. Considering the currently growing enzyme market for efficient and novel biocatalysts, data mining is a promising source for novel, as yet uncharacterised enzymes, especially from halophilic or halotolerant Bacillaceae, which offer great potential to meet industrial needs. Both halophilic bacteria Pontibacillus marinus DSM 16465ᵀ and Alkalibacillus haloalkaliphilus DSM 5271ᵀ and both halotolerant bacteria Metabacillus indicus DSM 16189 and Litchfieldia alkalitelluris DSM 16976ᵀ served as a source for the four new subtilisins SPPM, SPAH, SPMI and SPLA. The protease genes were cloned and expressed in Bacillus subtilis DB104. Purification to apparent homogeneity was achieved by ethanol precipitation, desalting and ion-exchange chromatography. Enzyme activity could be observed between pH 5.0-12.0 with an optimum for SPPM, SPMI and SPLA around pH 9.0 and for SPAH at pH 10.0. The optimal temperature for SPMI and SPLA was 70 °C and for SPPM and SPAH 55 °C and 50 °C, respectively. All proteases showed high stability towards 5\% (w/v) SDS and were active even at NaCl concentrations of 5 M. The four proteases demonstrate potential for future biotechnological applications.}, language = {en} } @article{FengSeiblerAlamietal.1999, author = {Feng, Yong-Qing and Seibler, Jost and Alami, Raouf and Eisen, Andrew and Westerman, Karen A. and Leboulch, Philippe and Fiering, Steven and Bouhassira, Eric E.}, title = {Site-specific chromosomal integration in mammalian cells: highly efficient CRE recombinase-mediated cassette exchange}, series = {Journal of Molecular Biology}, volume = {292}, journal = {Journal of Molecular Biology}, number = {4}, issn = {0022-2836}, doi = {10.1006/jmbi.1999.3113}, pages = {779 -- 785}, year = {1999}, language = {en} } @article{Feuerriegel2001, author = {Feuerriegel, Uwe}, title = {Trennen und Trocknen. FH Aachen verf{\"u}gt {\"u}ber einen Zentrifugentrockner im Technikumsmaßstab}, series = {Lebensmitteltechnik. 33 (2001), H. 7-8}, journal = {Lebensmitteltechnik. 33 (2001), H. 7-8}, isbn = {0047-4290}, pages = {22 -- 23}, year = {2001}, language = {de} }