@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{HoffstadtCheenakulaNikolauszetal.2023,
  author    = {Hoffstadt, Kevin and Cheenakula, Dheeraja and Nikolausz, Marcell and Krafft, Simone and Harms, Hauke and Kuperjans, Isabel},
  title     = {Design and construction of a new reactor for flexible biomethanation of hydrogen},
  series = {Fermentation},
  volume    = {9},
  journal   = {Fermentation},
  number    = {8},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2311-5637},
  doi       = {10.3390/fermentation9080774},
  pages     = {1 -- 16},
  year      = {2023},
  abstract  = {The increasing share of renewable electricity in the grid drives the need for sufficient storage capacity. Especially for seasonal storage, power-to-gas can be a promising approach. Biologically produced methane from hydrogen produced from surplus electricity can be used to substitute natural gas in the existing infrastructure. Current reactor types are not or are poorly optimized for flexible methanation. Therefore, this work proposes a new reactor type with a plug flow reactor (PFR) design. Simulations in COMSOL Multiphysics ® showed promising properties for operation in laminar flow. An experiment was conducted to support the simulation results and to determine the gas fraction of the novel reactor, which was measured to be 29\%. Based on these simulations and experimental results, the reactor was constructed as a 14 m long, 50 mm diameter tube with a meandering orientation. Data processing was established, and a step experiment was performed. In addition, a kLa of 1 h-1 was determined. The results revealed that the experimental outcomes of the type of flow and gas fractions are in line with the theoretical simulation. The new design shows promising properties for flexible methanation and will be tested.},
  language  = {en}
}
@article{TrappLammersEngudaretal.2023,
  author    = {Trapp, Svenja and Lammers, Tom and Engudar, Gokce and Hoehr, Cornelia and Denkova, Antonia G. and Paulßen, Elisabeth and de Kruijff, Robin M.},
  title     = {Membrane-based microfluidic solvent extraction of Ga-68 from aqueous Zn solutions: towards an automated cyclotron production loop},
  series = {EJNMMI Radiopharmacy and Chemistry},
  volume    = {2023},
  journal   = {EJNMMI Radiopharmacy and Chemistry},
  number    = {8, Article number: 9},
  publisher = {Springer Nature},
  issn      = {2365-421X},
  doi       = {10.1186/s41181-023-00195-2},
  pages     = {1 -- 14},
  year      = {2023},
  language  = {en}
}
@unpublished{GreinerJerominSitholeetal.2023,
  author    = {Greiner, Lasse and Jeromin, G{\"u}nter Erich and Sithole, Patience and Petersen, Soenke},
  title     = {Preprint: Studies on the enzymatic reduction of levulinic acid using Chiralidon-R and Chiralidon-S},
  series = {ChemRxiv},
  journal   = {ChemRxiv},
  doi       = {10.26434/chemrxiv-2023-jlvcv},
  pages     = {13 Seiten},
  year      = {2023},
  abstract  = {The enzymatic reduction of levulinic acid by the chiral catalysts Chiralidon-R and Chiralidon-S which are commercially available superabsorbed alcohol dehydrogenases is described. The Chiralidon®-R/S reduces the levulinic acid to the (R,S)-4-hydroxy valeric acid and the (R)- or (S)- gamma-valerolactone.},
  language  = {en}
}
@techreport{SiegertBongaertsWagneretal.2022,
  author    = {Siegert, Petra and Bongaerts, Johannes and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Selmer, Thorsten},
  title     = {Abschlussbericht zum Projekt zur {\"U}berwachung biotechnologischer Prozesse mittels Diacetyl-/Acetoin-Biosensor und Evaluierung von Acetoin-Reduktasen zur Verwendung in Biotransformationen},
  address   = {Aachen},
  organization    = {FH Aachen},
  pages     = {16 Seiten},
  year      = {2022},
  language  = {de}
}
@techreport{HaegerBongaertsSiegert2023,
  author    = {Haeger, Gerrit and Bongaerts, Johannes and Siegert, Petra},
  title     = {Abschlussbericht Teil II: Eingehende Darstellung Neue biobasierte Lipopeptide aus nachhaltiger Produktion (LipoPep)},
  pages     = {17Seiten},
  year      = {2023},
  language  = {de}
}
@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{BlockMayWetzeletal.2023,
  author    = {Block, Franziska and May, Alexander and Wetzel, Katharina and Adels, Klaudia and Elbers, Gereon and Schulze, Margit and Monakhova, Yulia},
  title     = {What is the best spectroscopic method for simultaneous analysis of organic acids and (poly)saccharides in biological matrices: Example of Aloe vera extracts?},
  series = {Talanta Open},
  volume    = {7},
  journal   = {Talanta Open},
  number    = {Art. No. 100220},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2666-8319},
  doi       = {10.1016/j.talo.2023.100220},
  pages     = {1 -- 9},
  year      = {2023},
  abstract  = {Several species of (poly)saccharides and organic acids can be found often simultaneously in various biological matrices, e.g., fruits, plant materials, and biological fluids. The analysis of such matrices sometimes represents a challenging task. Using Aloe vera (A. vera) plant materials as an example, the performance of several spectro-scopic methods (80 MHz benchtop NMR, NIR, ATR-FTIR and UV-vis) for the simultaneous analysis of quality parameters of this plant material was compared. The determined parameters include (poly)saccharides such as aloverose, fructose and glucose as well as organic acids (malic, lactic, citric, isocitric, acetic, fumaric, benzoic and sorbic acids). 500 MHz NMR and high-performance liquid chromatography (HPLC) were used as the reference methods. UV-vis data can be used only for identification of added preservatives (benzoic and sorbic acids) and drying agent (maltodextrin) and semiquantitative analysis of malic acid. NIR and MIR spectroscopies combined with multivariate regression can deliver more informative overview of A. vera extracts being able to additionally quantify glucose, aloverose, citric, isocitric, malic, lactic acids and fructose. Low-field NMR measurements can be used for the quantification of aloverose, glucose, malic, lactic, acetic, and benzoic acids. The benchtop NMR method was successfully validated in terms of robustness, stability, precision, reproducibility and limit of detection (LOD) and quantification (LOQ), respectively. All spectroscopic techniques are useful for the screening of (poly)saccharides and organic acids in plant extracts and should be applied according to its availability as well as information and confidence required for the specific analytical goal. Benchtop NMR spectroscopy seems to be the most feasible solution for quality control of A. vera products.},
  language  = {en}
}
@article{WeldenJablonskiWegeetal.2021,
  author    = {Welden, Rene and Jablonski, Melanie and Wege, Christina and Keusgen, Michael and Wagner, Patrick Hermann and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase},
  series = {Biosensors},
  volume    = {11},
  journal   = {Biosensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-6374},
  doi       = {10.3390/bios11060171},
  pages     = {Artikel 171},
  year      = {2021},
  abstract  = {The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte's pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS.},
  language  = {en}
}
@article{WeldenPoghossianVahidpouretal.2022,
  author    = {Welden, Melanie and Poghossian, Arshak and Vahidpour, Farnoosh and Wendlandt, Tim and Keusgen, Michael and Wege, Christina and Sch{\"o}ning, Michael Josef},
  title     = {Towards multi-analyte detection with field-effect capacitors modified with tobacco mosaic virus bioparticles as enzyme nanocarriers},
  series = {Biosensors},
  volume    = {12},
  journal   = {Biosensors},
  number    = {1},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-6374},
  doi       = {10.3390/bios12010043},
  pages     = {Artikel 43},
  year      = {2022},
  abstract  = {Utilizing an appropriate enzyme immobilization strategy is crucial for designing enzyme-based biosensors. Plant virus-like particles represent ideal nanoscaffolds for an extremely dense and precise immobilization of enzymes, due to their regular shape, high surface-to-volume ratio and high density of surface binding sites. In the present work, tobacco mosaic virus (TMV) particles were applied for the co-immobilization of penicillinase and urease onto the gate surface of a field-effect electrolyte-insulator-semiconductor capacitor (EISCAP) with a p-Si-SiO₂-Ta₂O₅ layer structure for the sequential detection of penicillin and urea. The TMV-assisted bi-enzyme EISCAP biosensor exhibited a high urea and penicillin sensitivity of 54 and 85 mV/dec, respectively, in the concentration range of 0.1-3 mM. For comparison, the characteristics of single-enzyme EISCAP biosensors modified with TMV particles immobilized with either penicillinase or urease were also investigated. The surface morphology of the TMV-modified Ta₂O₅-gate was analyzed by scanning electron microscopy. Additionally, the bi-enzyme EISCAP was applied to mimic an XOR (Exclusive OR) enzyme logic gate.},
  language  = {en}
}