@article{HuckPoghossianWagneretal.2012,
  author    = {Huck, Christina and Poghossian, Arshak and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Combined amperometric/field-effect sensor for the detection of dissolved hydrogen},
  series = {Sensors and actuators B: Chemical},
  volume    = {187},
  journal   = {Sensors and actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2012.10.050},
  pages     = {168 -- 173},
  year      = {2012},
  abstract  = {Real-time and reliable monitoring of the biogas process is crucial for a stable and efficient operation of biogas production in order to avoid digester breakdowns. The concentration of dissolved hydrogen (H₂) represents one of the key parameters for biogas process control. In this work, a one-chip integrated combined amperometric/field-effect sensor for monitoring the dissolved H₂ concentration has been developed for biogas applications. The combination of two different transducer principles might allow a more accurate and reliable measurement of dissolved H₂ as an early warning indicator of digester failures. The feasibility of the approach has been demonstrated by simultaneous amperometric/field-effect measurements of dissolved H₂ concentrations in electrolyte solutions. Both, the amperometric and the field-effect transducer show a linear response behaviour in the H₂ concentration range from 0.1 to 3\% (v/v) with a slope of 198.4 ± 13.7 nA/\% (v/v) and 14.9 ± 0.5 mV/\% (v/v), respectively.},
  language  = {en}
}
@article{HuckPoghossianKerroumietal.2014,
  author    = {Huck, Christina and Poghossian, Arshak and Kerroumi, Iman and Schusser, Sebastian and B{\"a}cker, Matthias and Zander, Willi and Schubert, J{\"u}rgen and Buniatyan, Vahe V. and Martirosyan, Norayr W. and Wagner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Multiparameter sensor chip with Barium Strontium Titanate as multipurpose material},
  series = {Electroanalysis},
  volume    = {26},
  journal   = {Electroanalysis},
  number    = {5},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-4109 (E-Journal); 1040-0397 (Print)},
  doi       = {10.1002/elan.201400076},
  pages     = {980 -- 987},
  year      = {2014},
  abstract  = {It is well known that biochemical and biotechnological processes are strongly dependent and affected by a variety of physico-chemical parameters such as pH value, temperature, pressure and electrolyte conductivity. Therefore, these quantities have to be monitored or controlled in order to guarantee a stable process operation, optimization and high yield. In this work, a sensor chip for the multiparameter detection of three physico-chemical parameters such as electrolyte conductivity, pH and temperature is realized using barium strontium titanate (BST) as multipurpose material. The chip integrates a capacitively coupled four-electrode electrolyte-conductivity sensor, a capacitive field-effect pH sensor and a thin-film Pt-temperature sensor. Due to the multifunctional properties of BST, it is utilized as final outermost coating layer of the processed sensor chip and serves as passivation and protection layer as well as pH-sensitive transducer material at the same time. The results of testing of the individual sensors of the developed multiparameter sensor chip are presented. In addition, a quasi-simultaneous multiparameter characterization of the sensor chip in buffer solutions with different pH value and electrolyte conductivity is performed. To study the sensor behavior and the suitability of BST as multifunctional material under harsh environmental conditions, the sensor chip was exemplarily tested in a biogas digestate.},
  language  = {en}
}
@article{HuckPoghossianBaeckeretal.2015,
  author    = {Huck, Christina and Poghossian, Arshak and B{\"a}cker, Matthias and Reisert, Steffen and Kramer, Friederike and Begoyan, Vardges K. and Buniatyan, Vahe V. and Sch{\"o}ning, Michael Josef},
  title     = {Multi-parameter sensing using high-k oxide of barium strontium titanate},
  series = {Physica status solidi (a)},
  volume    = {212},
  journal   = {Physica status solidi (a)},
  number    = {6},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201431911},
  pages     = {1259},
  year      = {2015},
  abstract  = {High-k perovskite oxide of barium strontium titanate (BST) represents a very attractive multi-functional transducer material for the development of (bio-)chemical sensors. In this work, a Si-based sensor chip containing Pt interdigitated electrodes covered with a thin BST layer (485 nm) has been developed for multi-parameter chemical sensing. The chip has been applied for the contactless measurement of the electrolyte conductivity, the detection of adsorbed charged macromolecules (positively charged polyelectrolytes of polyethylenimine) and the concentration of hydrogen peroxide (H2O2) vapor. The experimental results of functional testing of individual sensors are presented. The mechanism of the BST sensitivity to charged polyelectrolytes and H2O2 vapor has been proposed and discussed.},
  language  = {en}
}
@article{HuckPoghossianBaeckeretal.2014,
  author    = {Huck, Christina and Poghossian, Arshak and B{\"a}cker, Matthias and Chaudhuri, S. and Zander, W. and Schubert, J. and Begoyan, V. K. and Buniatyan, V. V. and Wagner, P. and Sch{\"o}ning, Michael Josef},
  title     = {Capacitively coupled electrolyte-conductivity sensor based on high-k material of barium strontium titanate},
  series = {Sensors and actuators. B: Chemical},
  journal   = {Sensors and actuators. B: Chemical},
  number    = {198},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2014.02.103},
  pages     = {102 -- 109},
  year      = {2014},
  language  = {en}
}
@article{HoskensRoerTolstikhinetal.2000,
  author    = {Hoskens, R.C.P. and Roer, T.G. van de and Tolstikhin, V.I. and F{\"o}rster, Arnold},
  title     = {Hot electron injection laser: vertically integrated transistor-laser structure for high-speed, low-chirp direct modulation},
  series = {LEOS 2000 : 2000 IEEE annual meeting conference proceedings; 13th annual meeting; IEEE Lasers and Electro-Optics Society 2000 annual meeting; 13-16 November 2000, The Westin Rio Mar Beach, Rio Grande, Puerto Rico. Vol. 2},
  journal   = {LEOS 2000 : 2000 IEEE annual meeting conference proceedings; 13th annual meeting; IEEE Lasers and Electro-Optics Society 2000 annual meeting; 13-16 November 2000, The Westin Rio Mar Beach, Rio Grande, Puerto Rico. Vol. 2},
  publisher = {IEEE Service Center},
  address   = {Piscataway, NJ},
  isbn      = {0-7803-5947-X},
  pages     = {444 -- 445},
  year      = {2000},
  language  = {en}
}
@article{HoskensTolstikhinFoersteretal.2000,
  author    = {Hoskens, R. C. P. and Tolstikhin, V.I. and F{\"o}rster, Arnold and Roer, T.G. van de},
  title     = {Vertically integrated transistor-laser structure, take 2},
  series = {WOCSDICE 2000, 24th Workshop on Compound Semiconductor Devices and Integrated Circuits held in Europe : May 29 - June 02, 2000, Aegean Sea, Greece.},
  journal   = {WOCSDICE 2000, 24th Workshop on Compound Semiconductor Devices and Integrated Circuits held in Europe : May 29 - June 02, 2000, Aegean Sea, Greece.},
  publisher = {Univ. of Michigan},
  address   = {Ann Arbor, Mich.},
  isbn      = {0970311109},
  pages     = {Getr. Z{\"a}hlung [ca. 200 S.]},
  year      = {2000},
  language  = {en}
}
@article{HonarvarfardGamellaPoghossianetal.2017,
  author    = {Honarvarfard, Elham and Gamella, Maria and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny},
  title     = {An enzyme-based reversible Controlled NOT (CNOT) logic gate operating on a semiconductor transducer},
  series = {Applied Materials Today},
  volume    = {9},
  journal   = {Applied Materials Today},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2352-9407},
  doi       = {10.1016/j.apmt.2017.08.003},
  pages     = {266 -- 270},
  year      = {2017},
  abstract  = {An enzyme-based biocatalytic system mimicking operation of a logically reversible Controlled NOT (CNOT) gate has been interfaced with semiconductor electronic transducers. Electrolyte-insulator-semiconductor (EIS) structures have been used to transduce chemical changes produced by the enzyme system to an electronically readable capacitive output signal using field-effect features of the EIS device. Two enzymes, urease and esterase, were immobilized on the insulating interface of EIS structure producing local pH changes performing XOR logic operation controlled by various combinations of the input signals represented by urea and ethyl butyrate. Another EIS transducer was functionalized with esterase only, thus performing Identity (ID) logic operation for the ethyl butyrate input. Both semiconductor devices assembled in parallel operated as a logically reversible CNOT gate. The present system, despite its simplicity, demonstrated for the first time logically reversible function of the enzyme system transduced electronically with the semiconductor devices. The biomolecular realization of a CNOT gate interfaced with semiconductors is promising for integration into complex biomolecular networks and future biosensor/biomedical applications.},
  language  = {en}
}
@article{HonarvarfardGamellaChannaveerappaetal.2017,
  author    = {Honarvarfard, Elham and Gamella, Maria and Channaveerappa, Devika and Darie, Costel C. and Poghossian, Arshak and Sch{\"o}ning, Michael Josef and Katz, Evgeny},
  title     = {Electrochemically Stimulated Insulin Release from a Modified Graphene-functionalized Carbon Fiber Electrode},
  series = {Electroanalysis},
  volume    = {29},
  journal   = {Electroanalysis},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-4109},
  doi       = {10.1002/elan.201700095},
  pages     = {1543 -- 1553},
  year      = {2017},
  abstract  = {A graphene-functionalized carbon fiber electrode was modified with adsorbed polyethylenimine to introduce amino functionalities and then with trigonelline and 4-carboxyphenylboronic acid covalently bound to the amino groups. The trigonelline species containing quarterized pyridine groups produced positive charge on the electrode surface regardless of the pH value, while the phenylboronic acid species were neutral below pH 8 and negatively charged above pH 9 (note that their pKa=8.4). The total charge on the monolayer-modified electrode was positive at the neutral pH and negative at pH > 9. Note that 4-carboxyphenylboronic acid was attached to the electrode surface in molar excess to trigonelline, thus allowing the negative charge to dominate on the electrode surface at basic pH. Negatively charged fluorescent dye-labeled insulin (insulin-FITC) was loaded on the modified electrode surface at pH 7.0 due to its electrostatic attraction to the positively charged interface. The local pH in close vicinity to the electrode surface was increased to ca. 9-10 due to consumption of H+ ions upon electrochemical reduction of oxygen proceeding at the potential of -1.0 V (vs. Ag/AgCl) applied on the modified electrode. The process resulted in recharging of the electrode surface to the negative value due to the formation of the negative charge on the phenylboronic acid groups, thus resulting in the electrostatic repulsion of insulin-FITC and stimulating its release from the electrode surface. The insulin release was characterized by fluorescence spectroscopy (using the FITC-labeled insulin), by electrochemical measurements on an iridium oxide, IrOx, electrode and by mass spectrometry. The graphene-functionalized carbon fiber electrode demonstrated significant advantages in the signal-stimulated insulin release comparing with the carbon fiber electrode without the graphene species.},
  language  = {en}
}
@article{HodelOrzatiMarsoetal.2000,
  author    = {Hodel, U. and Orzati, A. and Marso, M. and Homann, O. and Fox, A. and Hart, A. v. d. and F{\"o}rster, Arnold and Kordos, P. and L{\"u}th, H.},
  title     = {A novel InAlAs/InGaAs layer structure for monolithically integrated photoreceiver},
  series = {Conference Proceedings: 2000 International Conference on Indium Phosphide and related materials},
  journal   = {Conference Proceedings: 2000 International Conference on Indium Phosphide and related materials},
  publisher = {IEEE Service Center},
  address   = {Piscataway, NJ},
  isbn      = {0-7803-6320-5},
  pages     = {466 -- 469},
  year      = {2000},
  language  = {en}
}
@article{HennemannKohlReisertetal.2013,
  author    = {Hennemann, J{\"o}rg and Kohl, Claus-Dieter and Reisert, Steffen and Kirchner, Patrick and Sch{\"o}ning, Michael Josef},
  title     = {Copper oxide nanofibres for detection of hydrogen peroxide vapour at high concentrations},
  series = {physica status solidi (a)},
  volume    = {210},
  journal   = {physica status solidi (a)},
  number    = {5},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1862-6319},
  doi       = {10.1002/pssa.201200775},
  pages     = {859 -- 863},
  year      = {2013},
  abstract  = {We present a sensor concept based on copper(II)oxide (CuO) nanofibres for the detection of hydrogen peroxide (H2O2) vapour in the percent per volume (\% v/v) range. The fibres were produced by using the electrospinning technique. To avoid water condensation in the pores, the fibres were initially modified by an exposure to H2S to get an enclosed surface. By a thermal treatment at 350 °C the fibres were oxidised back to CuO. Thereby, the visible pores disappear which was verified by SEM analysis. The fibres show a decrease of resistance with increasing H2O2 concentration which is due to the fact that hydrogen peroxide is an oxidising gas and CuO a p-type semiconductor. The sensor shows a change of resistance within the minute range to the exposure until the maximum concentration of 6.9\% v/v H2O2. At operating temperatures below 450 °C the corresponding sensor response to a concentration of 4.1\% v/v increases. The sensor shows a good reproducibility of the signal at different measurements. CuO seems to be a suitable candidate for the detection of H2O2 vapour at high concentrations. Resistance behaviour of the sensor under exposure to H2O2 vapours between 2.3 and 6.9\% v/v at an operating temperature of 450 °C.},
  language  = {en}
}
@article{HenkenOosterhuisOehlschlaegeretal.2012,
  author    = {Henken, F. E. and Oosterhuis, K. and {\"O}hlschl{\"a}ger, Peter and Bosch, L. and Hooijberg, E. and Haanen, J. B. A. G. and Steenbergen, R. D. M.},
  title     = {Preclinical safety evaluation of DNA vaccines encoding modified HPV16 E6 and E7},
  series = {Vaccine},
  volume    = {30},
  journal   = {Vaccine},
  number    = {28},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0264-410X},
  doi       = {10.1016/j.vaccine.2012.04.013},
  pages     = {4259 -- 4266},
  year      = {2012},
  abstract  = {Persistent infection with high-risk human papillomaviruses (hrHPV) can result in the formation of anogenital cancers. As hrHPV proteins E6 and E7 are required for cancer initiation and maintenance, they are ideal targets for immunotherapeutic interventions. Previously, we have described the development of DNA vaccines for the induction of HPV16 E6 and E7 specific T cell immunity. These vaccines consist of 'gene-shuffled' (SH) versions of HPV16 E6 and E7 that were fused to Tetanus Toxin Fragment C domain 1 (TTFC) and were named TTFC-E6SH and TTFC-E7SH. Gene-shuffling was performed to avoid the risk of inducing malignant transformation at the vaccination site. Here, we describe the preclinical safety evaluation of these candidate vaccines by analysis of their transforming capacity in vitro using established murine fibroblasts (NIH 3T3 cells) and primary human foreskin keratinocytes (HFKs). We demonstrate that neither ectopic expression of TTFC-E6SH and TTFC-E7SH alone or in combination enabled NIH 3T3 cells to form colonies in soft agar. In contrast, expression of HPV16 E6WT and E7WT alone or in combination resulted in effective transformation. Similarly, retroviral transduction of HFKs from three independent donors with both TTFC-E6SH and TTFC-E7SH alone or in combination did not show any signs of immortalization. In contrast, the combined expression of E6WT and E7WT induced immortalization in HFKs from all donors. Based on these results we consider it justified to proceed to clinical evaluation of DNA vaccines encoding TTFC-E6SH and TTFC-E7SH in patients with HPV16 associated (pre)malignancies.},
  language  = {en}
}
@article{HeineHerrmannSelmeretal.2014,
  author    = {Heine, A. and Herrmann, G. and Selmer, Thorsten and Terwesten, F. and Buckel, W. and Reuter, K.},
  title     = {High resolution crystal structure of clostridium propionicum β-Alanyl-CoA:Ammonia Lyase, a new member of the "Hot Dog Fold" protein superfamily},
  series = {Proteins},
  volume    = {82},
  journal   = {Proteins},
  number    = {9},
  publisher = {Wiley-Liss},
  address   = {New York},
  issn      = {1097-0134 (E-Journal); 0887-3585 (Print)},
  doi       = {10.1002/prot.24557},
  pages     = {2041 -- 2053},
  year      = {2014},
  abstract  = {Clostridium propionicum is the only organism known to ferment β-alanine, a constituent of coenzyme A (CoA) and the phosphopantetheinyl prosthetic group of holo-acyl carrier protein. The first step in the fermentation is a CoA-transfer to β-alanine. Subsequently, the resulting β-alanyl-CoA is deaminated by the enzyme β-alanyl-CoA:ammonia lyase (Acl) to reversibly form ammonia and acrylyl-CoA. We have determined the crystal structure of Acl in its apo-form at a resolution of 0.97 {\AA} as well as in complex with CoA at a resolution of 1.59 {\AA}. The structures reveal that the enyzme belongs to a superfamily of proteins exhibiting a so called "hot dog fold" which is characterized by a five-stranded antiparallel β-sheet with a long α-helix packed against it. The functional unit of all "hot dog fold" proteins is a homodimer containing two equivalent substrate binding sites which are established by the dimer interface. In the case of Acl, three functional dimers combine to a homohexamer strongly resembling the homohexamer formed by YciA-like acyl-CoA thioesterases. Here, we propose an enzymatic mechanism based on the crystal structure of the Acl·CoA complex and molecular docking. Proteins 2014; 82:2041-2053. © 2014 Wiley Periodicals, Inc.},
  language  = {en}
}
@article{HeiduschkaRomannEckenetal.2001,
  author    = {Heiduschka, P. and Romann, I. and Ecken, H. and Sch{\"o}ning, Michael Josef and Schuhmann, W. and Thanos, S.},
  title     = {Defined adhesion and growth of neurones on artificial structured substrates},
  series = {Scaling down in electrochemistry : electrochemical micro- and nanosystem technology ; proceedings of the 3rd International Symposium on Electrochemical Microsystem Technologies, Garmisch-Patenkirchen, Germany, 11 - 15 September 2000 / ed. by J. W. Schultz},
  journal   = {Scaling down in electrochemistry : electrochemical micro- and nanosystem technology ; proceedings of the 3rd International Symposium on Electrochemical Microsystem Technologies, Garmisch-Patenkirchen, Germany, 11 - 15 September 2000 / ed. by J. W. Schultz},
  publisher = {Elsevier [u.a.]},
  address   = {Amsterdam [u.a.]},
  isbn      = {0-08-044014-2},
  pages     = {299 -- 307},
  year      = {2001},
  language  = {en}
}
@article{HeidenTurekSchoening2011,
  author    = {Heiden, W. and Turek, M. and Sch{\"o}ning, Michael Josef},
  title     = {TasteIT : Analyzing chemical sensor data using fuzzy logic},
  publisher = {IEEE},
  address   = {New York},
  isbn      = {978-1-4244-9910-6},
  pages     = {1 -- 6},
  year      = {2011},
  language  = {en}
}
@article{HeidenTurekSchoening2011,
  author    = {Heiden, W. and Turek, M. and Sch{\"o}ning, Michael Josef},
  title     = {Analysis of chemical sensor data},
  series = {Proceedings of the 4th Russian-German Workshop "Innovation Information Technologies: Theory and practice" : Ufa, Russia, April 8-13, 2011 / eds. Yupsova, Nafisa ...},
  journal   = {Proceedings of the 4th Russian-German Workshop "Innovation Information Technologies: Theory and practice" : Ufa, Russia, April 8-13, 2011 / eds. Yupsova, Nafisa ...},
  publisher = {State Aviation Technical Univ.},
  address   = {Ufa},
  isbn      = {978-5-4221-0159-7},
  pages     = {76 -- 81},
  year      = {2011},
  language  = {en}
}
@article{HandtkeVollandMethlingetal.2014,
  author    = {Handtke, Stefan and Volland, Sonja and Methling, Karen and Albrecht, Dirk and Becher, D{\"o}rte and Nehls, Jenny and Bongaerts, Johannes and Maurer, Karl-Heinz and Lalk, Michael and Liesegang, Heiko and Voigt, Birgit and Daniel, Rolf and Hecker, Michael},
  title     = {Cell physiology of the biotechnological relevant bacterium Bacillus pumilus - An omics-based approach},
  series = {Journal of Biotechnology},
  journal   = {Journal of Biotechnology},
  number    = {192(A)},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-4863 (E-Journal); 0168-1656 (Print)},
  doi       = {10.1016/j.jbiotec.2014.08.028},
  pages     = {204 -- 214},
  year      = {2014},
  abstract  = {Members of the species Bacillus pumilus get more and more in focus of the biotechnological industry as potential new production strains. Based on exoproteome analysis, B. pumilus strain Jo2, possessing a high secretion capability, was chosen for an omics-based investigation. The proteome and metabolome of B. pumilus cells growing either in minimal or complex medium was analyzed. In total, 1542 proteins were identified in growing B. pumilus cells, among them 1182 cytosolic proteins, 297 membrane and lipoproteins and 63 secreted proteins. This accounts for about 43\% of the 3616 proteins encoded in the B. pumilus Jo2 genome sequence. By using GC-MS, IP-LC/MS and H NMR methods numerous metabolites were analyzed and assigned to reconstructed metabolic pathways. In the genome sequence a functional secretion system including the components of the Sec- and Tat-secretion machinery was found. Analysis of the exoproteome revealed secretion of about 70 proteins with predicted secretion signals. In addition, selected production-relevant genome features such as restriction modification systems and NRPS clusters of B. pumilus Jo2 are discussed.},
  language  = {en}
}
@article{HamadBilattoAdlyetal.2016,
  author    = {Hamad, E. M. and Bilatto, S. E. R. and Adly, N. Y. and Correa, D. S. and Wolfrum, B. and Sch{\"o}ning, Michael Josef and Offenh{\"a}usser, A. and Yakushenko, A.},
  title     = {Inkjet printing of UV-curable adhesive and dielectric inks for microfluidic devices},
  series = {Lab on a Chip},
  volume    = {16},
  journal   = {Lab on a Chip},
  number    = {1},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1473-0189},
  doi       = {10.1039/C5LC01195G},
  pages     = {70 -- 74},
  year      = {2016},
  abstract  = {Bonding of polymer-based microfluidics to polymer substrates still poses a challenge for Lab-On-a-Chip applications. Especially, when sensing elements are incorporated, patterned deposition of adhesives with curing at ambient conditions is required. Here, we demonstrate a fabrication method for fully printed microfluidic systems with sensing elements using inkjet and stereolithographic 3D-printing.},
  language  = {en}
}
@article{HaegerWirgesTanzmannetal.2023,
  author    = {Haeger, Gerrit and Wirges, Jessika and Tanzmann, Nicole and Oyen, Sven and Jolmes, Tristan and Jaeger, Karl-Erich and Sch{\"o}rken, Ulrich and Bongaerts, Johannes and Siegert, Petra},
  title     = {Chaperone assisted recombinant expression of a mycobacterial aminoacylase in Vibrio natriegens and Escherichia coli capable of N-lauroyl-L-amino acid synthesis},
  series = {Microbial Cell Factories},
  journal   = {Microbial Cell Factories},
  number    = {22},
  publisher = {Springer Nature},
  issn      = {1475-2859},
  doi       = {10.1186/s12934-023-02079-1},
  pages     = {Article number: 77 (2023)},
  year      = {2023},
  abstract  = {Background Aminoacylases are highly promising enzymes for the green synthesis of acyl-amino acids, potentially replacing the environmentally harmful Schotten-Baumann reaction. Long-chain acyl-amino acids can serve as strong surfactants and emulsifiers, with application in cosmetic industries. Heterologous expression of these enzymes, however, is often hampered, limiting their use in industrial processes. Results We identified a novel mycobacterial aminoacylase gene from Mycolicibacterium smegmatis MKD 8, cloned and expressed it in Escherichia coli and Vibrio natriegens using the T7 overexpression system. The recombinant enzyme was prone to aggregate as inclusion bodies, and while V. natriegens Vmax™ could produce soluble aminoacylase upon induction with isopropyl β-d-1-thiogalactopyranoside (IPTG), E. coli BL21 (DE3) needed autoinduction with lactose to produce soluble recombinant protein. We successfully conducted a chaperone co-expression study in both organisms to further enhance aminoacylase production and found that overexpression of chaperones GroEL/S enhanced aminoacylase activity in the cell-free extract 1.8-fold in V. natriegens and E. coli. Eventually, E. coli ArcticExpress™ (DE3), which co-expresses cold-adapted chaperonins Cpn60/10 from Oleispira antarctica, cultivated at 12 °C, rendered the most suitable expression system for this aminoacylase and exhibited twice the aminoacylase activity in the cell-free extract compared to E. coli BL21 (DE3) with GroEL/S co-expression at 20 °C. The purified aminoacylase was characterized based on hydrolytic activities, being most stable and active at pH 7.0, with a maximum activity at 70 °C, and stability at 40 °C and pH 7.0 for 5 days. The aminoacylase strongly prefers short-chain acyl-amino acids with smaller, hydrophobic amino acid residues. Several long-chain amino acids were fairly accepted in hydrolysis as well, especially N-lauroyl-L-methionine. To initially evaluate the relevance of this aminoacylase for the synthesis of N-acyl-amino acids, we demonstrated that lauroyl-methionine can be synthesized from lauric acid and methionine in an aqueous system. Conclusion Our results suggest that the recombinant enzyme is well suited for synthesis reactions and will thus be further investigated.},
  language  = {en}
}
@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}
}
@article{HaegerJolmesOyenetal.2024,
  author    = {Haeger, Gerrit and Jolmes, Tristan and Oyen, Sven and Jaeger, Karl-Erich and Bongaerts, Johannes and Sch{\"o}rken, Ulrich and Siegert, Petra},
  title     = {Novel recombinant aminoacylase from Paraburkholderia monticola capable of N-acyl-amino acid synthesis},
  series = {Applied Microbiology and Biotechnology},
  journal   = {Applied Microbiology and Biotechnology},
  number    = {108},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1432-0614},
  doi       = {10.1007/s00253-023-12868-8},
  pages     = {14 Seiten},
  year      = {2024},
  abstract  = {N-Acyl-amino acids can act as mild biobased surfactants, which are used, e.g., in baby shampoos. However, their chemical synthesis needs acyl chlorides and does not meet sustainability criteria. Thus, the identification of biocatalysts to develop greener synthesis routes is desirable. We describe a novel aminoacylase from Paraburkholderia monticola DSM 100849 (PmAcy) which was identified, cloned, and evaluated for its N-acyl-amino acid synthesis potential. Soluble protein was obtained by expression in lactose autoinduction medium and co-expression of molecular chaperones GroEL/S. Strep-tag affinity purification enriched the enzyme 16-fold and yielded 15 mg pure enzyme from 100 mL of culture. Biochemical characterization revealed that PmAcy possesses beneficial traits for industrial application like high temperature and pH-stability. A heat activation of PmAcy was observed upon incubation at temperatures up to 80 °C. Hydrolytic activity of PmAcy was detected with several N-acyl-amino acids as substrates and exhibited the highest conversion rate of 773 U/mg with N-lauroyl-L-alanine at 75 °C. The enzyme preferred long-chain acyl-amino-acids and displayed hardly any activity with acetyl-amino acids. PmAcy was also capable of N-acyl-amino acid synthesis with good conversion rates. The best synthesis results were obtained with the cationic L-amino acids L-arginine and L-lysine as well as with L-leucine and L-phenylalanine. Exemplarily, L-phenylalanine was acylated with fatty acids of chain lengths from C8 to C18 with conversion rates of up to 75\%. N-lauroyl-L-phenylalanine was purified by precipitation, and the structure of the reaction product was verified by LC-MS and NMR.},
  language  = {en}
}