@article{SiqueiraBaeckerPoghossianetal.2010,
  author    = {Siqueira, Jos{\´e} R. Jr. and B{\"a}cker, Matthias and Poghossian, Arshak and Zucolotto, Valtencir and Oliveira, Osvaldo N. Jr. and Sch{\"o}ning, Michael Josef},
  title     = {Associating biosensing properties with the morphological structure of multilayers containing carbon nanotubes on field-effect devices},
  series = {Physica Status Solidi (A)},
  volume    = {207},
  journal   = {Physica Status Solidi (A)},
  number    = {4},
  publisher = {Wiley-VCH},
  address   = {Berlin},
  issn      = {1862-6300},
  doi       = {10.1002/pssa.200983301},
  pages     = {781 -- 786},
  year      = {2010},
  abstract  = {The control of molecular architecture provided by the layer-by-layer (LbL) technique has led to enhanced biosensors, in which advantageous features of distinct materials can be combined. Full optimization of biosensing performance, however, is only reached if the film morphology is suitable for the principle of detection of a specific biosensor. In this paper, we report a detailed morphology analysis of LbL films made with alternating layers of single-walled carbon nanotubes (SWNTs) and polyamidoamine (PAMAM) dendrimers, which were then covered with a layer of penicillinase (PEN). An optimized performance to detect penicillin G was obtained with 6-bilayer SWNT/PAMAM LbL films deposited on p-Si-SiO2-Ta2O5 chips, used in biosensors based on a capacitive electrolyte-insulator-semiconductor (EIS) and a light-addressable potentiometric sensor (LAPS) structure, respectively. Field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) images indicated that the LbL films were porous, with a large surface area due to interconnection of SWNT into PAMAM layers. This morphology was instrumental for the adsorption of a larger quantity of PEN, with the resulting LbL film being highly stable. The experiments to detect penicillin were performed with constant-capacitance (ConCap) and constant-current (CC) measurements for EIS and LAPS sensors, respectively, which revealed an enhanced detection signal and sensitivity of ca. 100 mV/decade for the field-effect sensors modified with the PAMAM/SWNT LbL film. It is concluded that controlling film morphology is essential for an enhanced performance of biosensors, not only in terms of sensitivity but also stability and response time.},
  language  = {en}
}
@article{RibitschHeumannKarletal.2012,
  author    = {Ribitsch, Doris and Heumann, Sonja and Karl, Wolfgang and Gerlach, Jochen and Leber, R. and Birner-Gruenberger, R. and Gruber, K. and Eiteljoerg, I. and Remler, Peter and Siegert, Petra and Lange, J. and Maurer, Karl-Heinz and Berg, G. and Guebitz, G. M. and Schwab, H.},
  title     = {Extracellular serine proteases from Stenotrophomonas maltophilia: Screening, isolation and heterologous expression in E. coli},
  series = {Journal of biotechnology},
  volume    = {157},
  journal   = {Journal of biotechnology},
  number    = {1},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-4863 (E-Journal); 0168-1656 (Print)},
  doi       = {10.1016/j.jbiotec.2011.09.025},
  pages     = {140 -- 147},
  year      = {2012},
  abstract  = {A large strain collection comprising antagonistic bacteria was screened for novel detergent proteases. Several strains displayed protease activity on agar plates containing skim milk but were inactive in liquid media. Encapsulation of cells in alginate beads induced protease production. Stenotrophomonas maltophilia emerged as best performer under washing conditions. For identification of wash-active proteases, four extracellular serine proteases called StmPr1, StmPr2, StmPr3 and StmPr4 were cloned. StmPr2 and StmPr4 were sufficiently overexpressed in E. coli. Expression of StmPr1 and StmPr3 resulted in unprocessed, insoluble protein. Truncation of most of the C-terminal domain which has been identified by enzyme modeling succeeded in expression of soluble, active StmPr1 but failed in case of StmPr3. From laundry application tests StmPr2 turned out to be a highly wash-active protease at 45 °C. Specific activity of StmPr2 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 17 ± 2 U/mg. In addition we determined the kinetic parameters and cleavage preferences of protease StmPr2.},
  language  = {en}
}
@inproceedings{BaeckerKochGeigeretal.2016,
  author    = {B{\"a}cker, Matthias and Koch, Claudia and Geiger, Fania and Eber, Fabian and Gliemann, Hartmut and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {A New Class of Biosensors Based on Tobacco Mosaic Virus and Coat Proteins as Enzyme Nanocarrier},
  series = {Procedia Engineering},
  volume    = {Vol. 168},
  booktitle = {Procedia Engineering},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2016.11.228},
  pages     = {618 -- 621},
  year      = {2016},
  language  = {en}
}
@article{RibitschKarlBirnerGruenbergeretal.2010,
  author    = {Ribitsch, Doris and Karl, Wolfgang and Birner-Gruenberger, R. and Gruber, K. and Eiteljoerg, I. and Remler, Peter and Wieland, S. and Siegert, Petra and Maurer, Karl-Heinz and Schwab, H.},
  title     = {C-terminal truncation of a metagenome-derived detergent protease for effective expression in E. coli},
  series = {Journal of biotechnology},
  volume    = {150},
  journal   = {Journal of biotechnology},
  number    = {3},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-4863 (E-Journal); 0168-1656 (Print)},
  doi       = {10.1016/j.jbiotec.2010.09.947},
  pages     = {408 -- 416},
  year      = {2010},
  abstract  = {Recently, a new alkaline protease named HP70 showing highest homology to extracellular serine proteases of Stenotrophomonas maltophilia and Xanthomonas campestris was found in the course of a metagenome screening for detergent proteases (Niehaus et al., submitted for publication). Attempts to efficiently express the enzyme in common expression hosts had failed. This study reports on the realization of overexpression in Escherichia coli after structural modification of HP70. Modelling of HP70 resulted in a two-domain structure, comprising the catalytic domain and a C-terminal domain which includes about 100 amino acids. On the basis of the modelled structure the enzyme was truncated by deletion of most of the C-terminal domain yielding HP70-C477. This structural modification allowed effective expression of active enzyme using E. coli BL21-Gold as the host. Specific activity of HP70-C477 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 30 ± 5 U/mg compared to 8 ± 1 U/mg of the native enzyme. HP70-C477 was most active at 40 °C and pH 7-11; these conditions are prerequisite for a potential application as detergent enzyme. Determination of kinetic parameters at 40 °C and pH = 9.5 resulted in KM = 0.23 ± 0.01 mM and kcat = 167.5 ± 3.6 s⁻¹. MS-analysis of peptide fragments obtained from incubation of HP70 and HP70-C477 with insulin B indicated that the C-terminal domain influences the cleavage preferences of the enzyme. Washing experiments confirmed the high potential of HP70-C477 as detergent protease.},
  language  = {en}
}