@article{WeldenSeverinsPoghossianetal.2022,
  author    = {Welden, Melanie and Severins, Robin and Poghossian, Arshak and Wege, Christina and Bongaerts, Johannes and Siegert, Petra and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Detection of acetoin and diacetyl by a tobacco mosaic virus-assisted field-effect biosensor},
  series = {Chemosensors},
  volume    = {10},
  journal   = {Chemosensors},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2227-9040},
  doi       = {10.3390/chemosensors10060218},
  pages     = {Artikel 218},
  year      = {2022},
  abstract  = {Acetoin and diacetyl have a major impact on the flavor of alcoholic beverages such as wine or beer. Therefore, their measurement is important during the fermentation process. Until now, gas chromatographic techniques have typically been applied; however, these require expensive laboratory equipment and trained staff, and do not allow for online monitoring. In this work, a capacitive electrolyte-insulator-semiconductor sensor modified with tobacco mosaic virus (TMV) particles as enzyme nanocarriers for the detection of acetoin and diacetyl is presented. The enzyme acetoin reductase from Alkalihalobacillus clausii DSM 8716ᵀ is immobilized via biotin-streptavidin affinity, binding to the surface of the TMV particles. The TMV-assisted biosensor is electrochemically characterized by means of leakage-current, capacitance-voltage, and constant capacitance measurements. In this paper, the novel biosensor is studied regarding its sensitivity and long-term stability in buffer solution. Moreover, the TMV-assisted capacitive field-effect sensor is applied for the detection of diacetyl for the first time. The measurement of acetoin and diacetyl with the same sensor setup is demonstrated. Finally, the successive detection of acetoin and diacetyl in buffer and in diluted beer is studied by tuning the sensitivity of the biosensor using the pH value of the measurement solution.},
  language  = {en}
}
@article{HaegerBongaertsSiegert2022,
  author    = {Haeger, Gerrit and Bongaerts, Johannes and Siegert, Petra},
  title     = {A convenient ninhydrin assay in 96-well format for amino acid-releasing enzymes using an air-stable reagent},
  series = {Analytical Biochemistry},
  journal   = {Analytical Biochemistry},
  number    = {624},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1096-0309},
  doi       = {10.1016/j.ab.2022.114819},
  pages     = {Artikel 114819},
  year      = {2022},
  abstract  = {An improved and convenient ninhydrin assay for aminoacylase activity measurements was developed using the commercial EZ Nin™ reagent. Alternative reagents from literature were also evaluated and compared. The addition of DMSO to the reagent enhanced the solubility of Ruhemann's purple (RP). Furthermore, we found that the use of a basic, aqueous buffer enhances stability of RP. An acidic protocol for the quantification of lysine was developed by addition of glacial acetic acid. The assay allows for parallel processing in a 96-well format with measurements microtiter plates.},
  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}
}