Christoph Syldatk

Karlsruhe Institute of Technology, Carlsruhe, Baden-Württemberg, Germany

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Publications (165)302.89 Total impact

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    ABSTRACT: A microtiter plate-based assay was developed to evaluate the ability of lipases to perform transesterifications when employed in different organic solvents. A 4-nitrophenol assay was carried out employing seven different lipase formulations and two fatty acid methyl esters with different chain lengths in a total of six organic solvents with logP values approximately between 1 and -1. This assay delivered results within comparatively short times measured by a color reaction and thus facilitates the choice of an enzyme-solvent combination for the synthesis of glycolipids. To validate the findings, glycolipid syntheses were performed using the same lipase formulation in the same solvents. When comparing the results obtained using the microtiter plate-based assay to the results of the glycolipid syntheses using the same lipases and solvents, matching results were obtained.
    Biotechnology Letters 11/2014; · 1.85 Impact Factor
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    ABSTRACT: Enzymatic synthesis of sugar fatty acid esters in organic solvents is a well-described procedure to synthesize glycolipids. This study aims at replacing these solvents with deep eutectic solvents (DES), a group of solvents that gained more and more interest during the last years, since they can be easily produced from non-toxic resources. Enzymatic glycolipid synthesis in deep eutectic solvents was investigated, employing Candida antarctica lipase B (Novozyme 435) in various deep eutectic solvents. A successful lipase-catalyzed synthesis of glucose fatty acid esters gave proof of this concept, while using the two deep eutectic solvents consisting of choline chloride and urea (CC : U) and choline chloride and glucose (CC : Glc). Additionally the DES consisting of choline chloride and glucose was observed to act as solvent and substrate for the synthesis at the same time.Practical application:Glycolipids find applications in many every-day products like cosmetic and pharmaceutical formulations, food and classic cleaning products, utilizing their good detergent or emulsification properties. Glycolipids can, among other routes, be synthesized via lipase-catalyzed reactions, which are often carried out in organic solvents. By replacing these organic solvents with more ecologically friendly solvents like deep eutectic solvents, the reaction might be improved and the amount of waste produced could be reduced.
    European Journal of Lipid Science and Technology 11/2014; · 2.27 Impact Factor
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    Chemie Ingenieur Technik 09/2014; 86(9). · 0.70 Impact Factor
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    C. Slomka, U. Engel, C. Syldatk, J. Rudat
    Chemie Ingenieur Technik 09/2014; 86(9). · 0.70 Impact Factor
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    Chemie Ingenieur Technik 09/2014; 86(9). · 0.70 Impact Factor
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    S. Dold, C. Syldatk, J. Rudat
    Chemie Ingenieur Technik 09/2014; 86(9). · 0.70 Impact Factor
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    ABSTRACT: Biosurfactants increasingly gain attention due to the manifold of possible applications and production on the basis of renewable resources. Owing to its various characteristics, Surfactin is one of the most studied biosurfactants. Since its discovery, several Surfactin producers have been identified, but their capacity to produce Surfactin has not been evaluated in a comparison. Six different Bacillus strains were analyzed regarding their ability to produce Surfactin in model fermentations with integrated foam fractionation, for in situ product enrichment and removal. Three of the investigated strains are commonly used in Surfactin production (ATCC 21332, DSM 3256, DSM 3258), whereas two Bacillus strains are described for the first time (DSM 1090, LM43a50°C) as Surfactin producers. Additionally, the Bacillus subtilis type strain DSM 10(T) was included in the evaluation. Interestingly, all strains, except DSM 3256, featured high values for Surfactin recovered from foam in comparison to other studies, ranging between 0.4 and 1.05 g. The fermentation process was characterized by calculating procedural parameters like substrate yield Y X/S, product yield Y P/X, specific growth rate μ, specific productivity q Surfactin, volumetric productivity q Surfactin, Surfactin and bacterial enrichment as well as Surfactin recovery. The strains differ most in specific and volumetric productivity; nevertheless, it is evident that it is not possible to name a Bacillus strain that is the most appropriate for the production of Surfactin under these conditions. In contrast, it becomes apparent that the choice of a specific strain should depend on the applied fermentation conditions.
    Applied microbiology and biotechnology. 08/2014;
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    ABSTRACT: Actinomycetales are known to produce various secondary metabolites including products with surface-active and emulsifying properties known as biosurfactants. In this study, the nonpathogenic actinomycetes Tsukamurella spumae and Tsukamurella pseudospumae are described as producers of extracellular trehalose lipid biosurfactants when grown on sunflower oil or its main component glyceryltrioleate. Crude extracts of the trehalose lipids were purified using silica gel chromatography. The structure of the two trehalose lipid components (TL A and TL B) was elucidated using a combination of matrix-assisted laser desorption/ionization time-of-flight/time-of-flight/tandem mass spectroscopy (MALDI-ToF-ToF/MS/MS) and multidimensional NMR experiments. The biosurfactants were identified as 1-α-glucopyranosyl-1-α-glucopyranosid carrying two acyl chains varying of C4 to C6 and C16 to C18 at the 2' and 3' carbon atom of one sugar unit. The trehalose lipids produced demonstrate surface-active behavior and emulsifying capacity. Classified as risk group 1 organisms, T. spumae and T. pseudospumae hold potential for the production of environmentally friendly surfactants.
    Applied Microbiology and Biotechnology 08/2014; · 3.81 Impact Factor
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    ABSTRACT: Economic and ecological reasons cause the industry to develop new innovative bio-based processes for the production of oil as renewable feedstock. Petroleum resources are expected to be depleted in the near future. Plant oils as sole substituent are highly criticized because of the competitive utilization of the agricultural area for food and energy feedstock production. Microbial lipids of oleaginous microorganisms are therefore a suitable alternative. To decrease production costs of microbial lipids and gain spatial independence from industrial sites of CO2 emission, a combination of heterotrophic and phototrophic cultivation with integrated CO2 recycling was investigated in this study. A feasibility study on a semi-pilot scale was conducted and showed that the cultivation of the oleaginous yeast Cryptococcus curvatus on a 1.2-L scale was sufficient to supply a culture of the oleaginous microalgae Phaeodactylum tricornutum in a 21-L bubble column reactor with CO2 while single cell oils were produced in both processes due to a nutrient limitation.
    Applied microbiology and biotechnology. 06/2014;
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    ABSTRACT: Oligopeptides are of high importance for various industrial applications, e.g. cosmetical or medical. Homooligomerizations and co-oligomerizations with anionic amino acid esters are well described but a successful synthesis of cationic heterooligopeptides has been missing so far. The present study reports the ficain-catalyzed heterooligomerizations of LysOEt with MetOEt, leading to cationic heterooligopeptides with a yield up to 49.5% (w/w). MALDI-ToF/ToF-MS analyses proved successful syntheses of cationic heterooligopeptides with a DP between 7 and 10 amino acid residues, with the enzyme exhibiting a clear preference for methionine. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.
    Journal of Peptide Science 05/2014; · 2.07 Impact Factor
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    ABSTRACT: The production of rhamnolipid biosurfactants by Pseudomonas aeruginosa is under complex control of a quorum sensing-dependent regulatory network. Due to a lack of understanding of the kinetics applicable to the process and relevant interrelations of variables, current processes for rhamnolipid production are based on heuristic approaches. To systematically establish a knowledge-based process for rhamnolipid production, a deeper understanding of the time-course and coupling of process variables is required. By combining reaction kinetics, stoichiometry, and experimental data, a process model for rhamnolipid production with P. aeruginosa PAO1 on sunflower oil was developed as a system of coupled ordinary differential equations (ODEs). In addition, cell density-based quorum sensing dynamics were included in the model. The model comprises a total of 36 parameters, 14 of which are yield coefficients and 7 of which are substrate affinity and inhibition constants. Of all 36 parameters, 30 were derived from dedicated experimental results, literature, and databases and 6 of them were used as fitting parameters. The model is able to describe data on biomass growth, substrates, and products obtained from a reference batch process and other validation scenarios. The model presented describes the time-course and interrelation of biomass, relevant substrates, and products on a process level while including a kinetic representation of cell density-dependent regulatory mechanisms.
    Applied Microbiology and Biotechnology 04/2014; · 3.81 Impact Factor
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    ABSTRACT: L-Malic acid and fumaric acid are C4 dicarboxylic organic acids and considered as promising chemical building blocks. They can be applied as food preservatives and acidulants in rust removal and as polymerization starter units. Molds of the genus Aspergillus are able to produce malic acid in large quantities from glucose and other carbon sources. In order to enhance the production potential of Aspergillus oryzae DSM 1863, production and consumption rates in an established bioreactor batch-process based on glucose were determined. At 35 °C, up to 42 g/L malic acid was produced in a 168-h batch process with fumaric acid as a by-product. In prolonged shaking flask experiments (353 h), the suitability of the alternative carbon sources xylose and glycerol at a carbon-to-nitrogen (C/N) ratio of 200:1 and the influence of different C/N ratios in glucose cultivations were tested. When using glucose, 58.2 g/L malic acid and 4.2 g/L fumaric acid were produced. When applying xylose or glycerol, both organic acids are produced but the formation of malic acid decreased to 45.4 and 39.4 g/L, respectively. Whereas the fumaric acid concentration was not significantly altered when cultivating with xylose (4.5 g/L), it is clearly enhanced by using glycerol (9.3 g/L). When using glucose as a carbon source, an increase or decrease of the C/N ratio did not influence malic acid production but had an enormous influence on fumaric acid production. The highest fumaric acid concentrations were determined at the highest C/N ratio (300:1, 8.44 g/L) and lowest at the lowest C/N ratio (100:1, 0.7 g/L).
    Applied Microbiology and Biotechnology 03/2014; · 3.81 Impact Factor
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    ABSTRACT: N-acetyl-glucosamine fatty acid esters were synthesized by a lipase-catalyzed transesterification with methyl hexanoate and N-acetyl-glucosamine, which resulted in the formation of 2-(Acetylamino)-2-deoxy-6-O-hexanoate-D-glucose, a novel glycolipid. Additionally N-butyryl-glucosamine was used for a similar synthesis, leading to the formation of 2-(Butyrylamino)-2-deoxy-6-O-hexanoate-D-glucose. The higher hydrophobicity of GlcNBu led to an increase in the overall yield and the initial reaction rate when compared to the reaction with GlcNAc. By pre-dissolving GlcNAc and GlcNBu in dimethyl sulfoxide (DMSO), it was possible to completely dissolve both sugars in the organic solvent, thus further enhancing the initial reaction rate and yield respectively.Practical applicationsGlycolipids are used in a wide range of applications, ranging from food, cosmetic and pharmaceutical formulations, where they can be used as emulsifiers or foaming agents to classic cleaning products, utilizing their good detergent properties. Further applications may include fields like membrane protein extraction, bioremediation or tertiary oil recovery. Novel glycolipids with tailor-made properties might be useful to improve any of the named applications and widen the diversity of available environmentally friendly surfactants, often termed “green surfactants”. Glycolipids are the most prominent example therefrom.
    European Journal of Lipid Science and Technology 01/2014; · 2.27 Impact Factor
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    ABSTRACT: The yeast strains Cryptococcus podzolicus, Trichosporon porosum and Pichia segobiensis were isolated from soil samples and identified as oleaginous yeast strains beneficial for the establishment of microbial production processes for sustainable lipid production suitable for several industrial applications. When cultured in bioreactors with glucose as the sole carbon source C. podzolicus yielded 31.8% lipid per dry biomass at 20°C, while T. porosum yielded 34.1% at 25°C and P. segobiensis 24.6% at 25°C. These amounts correspond to lipid concentrations of 17.97 g/L, 17.02 g/L and 12.7 g/L and volumetric productivities of 0.09 g/Lh, 0.1 g/Lh and 0.07 g/Lh, respectively. During the culture of C. podzolicus 30 g/l gluconic acid was detected as by-product in the culture broth and 12 g/L gluconic acid in T. porosum culture. The production of gluconic acid was eliminated for both strains when glucose was substituted by xylose as the carbon source. Using xylose lipid yields were 11.1 g/L and 13.9 g/L, corresponding to 26.8% and 33.4% lipid per dry biomass and a volumetric productivity of 0.07 g/Lh and 0.09 g/Lh, for C. podzolicus and T. porosum respectively. The fatty acid profile analysis showed that oleic acid was the main component (39.6 to 59.4%) in all three strains and could be applicable for biodiesel production. Palmitic acid (18.4 to 21.1%) and linolenic acid (7.5 to 18.7%) are valuable for cosmetic applications. P. segobiensis had a considerable amount of palmitoleic acid (16% content) and may be suitable for medical applications.
    AMB Express. 01/2014; 4:24.
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    ABSTRACT: Influence of different parameters on biosurfactant (BS) activity was carried out on strains that were isolated from the polychaetes Megalomma claparedei, Sabella spallanzanii and Branchiomma luctuosum and additional 30 strains that were previously identified as potential BS producers from crude oil enrichments of the same polychaete specimens. The selection of BS-producing strains from polychaete natural samples was carried out by using standard screening tests. The BS activity by each isolate was evaluated for the effect of salinity and temperature on emulsion production and surface tension reduction, during incubation in mineral medium supplemented with tetradecane or diesel oil. All isolates showed a similar time course of BS activity, and the latter was more influenced by salinity rather than temperature. Some of the BS producers belonged to genera that have not (i.e. Citricoccus, Cellulophaga, Tenacibaculum and Maribacter) or have poorly been (Psychrobacter, Vibrio, and Pseudoalteromonas) reported as able to produce BSs. This is remarkable as some of them have previously been detected in hydrocarbon-enriched samples. Results confirm that filter-feeding polychaetes are an efficient source for the isolation of BS producers.
    Environmental Science and Pollution Research 10/2013; · 2.76 Impact Factor
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    Mareike Perzborn, Christoph Syldatk, Jens Rudat
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    ABSTRACT: Diketopiperazines (DKPs) are cyclic dipeptides, representing an abundant class of biologically active natural compounds. Despite their widespread occurrence in nature, little is known about their degradation. In this study, the enzymatical and microbial cleavage of DKPs was investigated. Peptidase catalyzed hydrolysis of certain DKPs was formerly reported, but could not be confirmed in this study. While testing additional peptidases and DKPs no degradation was detected, indicating peptidase stability of the peptide bond in cyclic dipeptides. Besides confirmation of the reported degradation of cyclo(l-Asp-l-Phe) by Paenibacillus chibensis (DSM 329) and Streptomyces flavovirens (DSM 40062), cleavage of cyclo(l-Asp-l-Asp) by DSM 329 was detected. Other DKPs were not hydrolyzed by both strains, demonstrating high substrate specificity. The degradation of cyclo(l-Asp-l-Phe) by DSM 40062 was shown to be inducible. Three strains, which are able to hydrolyze hydantoins and dihydropyrimidines, were identified for the degradation of DKPs: Leifsonia sp. K3 (DSM 27212) and Bacillus sp. A16 (DSM 25052) cleaved cyclo(dl-Ala-dl-Ala) and cyclo(l-Gly-l-Phe), and Rhizobium sp. NA04-01 (DSM 24917) degraded cyclo(l-Asp-l-Phe), cyclo(l-Gly-l-Phe) and cyclo(l-Asp-l-Asp). The first enantioselective cleavage of cyclo(dl-Ala-dl-Ala) was detected with the newly isolated strains Paenibacillus sp. 32A (DSM 27214) and Microbacterium sp. 40A (DSM 27211). Cyclo(l-Ala-d-Ala) and cyclo(l-Ala-l-Ala) were completely degraded, whereas the enantiomer cyclo(d-Ala-d-Ala) was not attacked. Altogether, five bacterial strains were newly identified for the cleavage of DKPs. These bacteria may be of value for industrial purposes, such as degradation of undesirable DKPs in food and drugs and production of (enantiopure) dipeptides and amino acids.
    AMB Express. 08/2013; 3(1):51.
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    ABSTRACT: Quorum sensing affects the regulation of more than 300 genes in Pseudomonas aeruginosa, influencing growth, biofilm formation, and the biosynthesis of several products. The quorum sensing regulation mechanisms are mostly described in a qualitative character. Particularly, in this study, the kinetics of N-butyryl-homoserine lactone (C4-HSL) and rhamnolipid formation in P. aeruginosa PAO1 were of interest. In this system, the expression of the rhamnolipid biosynthesis genes rhlAB is directly coupled to the C4-HSL concentration via the rhl system. Batch cultivations in a bioreactor with sunflower oil have been used for these investigations. 3-oxo-dodecanoyl-homoserine lactone (3o-C12-HSL) displayed a lipophilic character and accumulated in the hydrophobic phase. Degradation of C4-HSL has been found to occur in the aqueous supernatant of the culture by yet unknown extracellular mechanisms, and production was found to be proportional to biomass concentration rather than by autoinduction mechanisms. Rhamnolipid production rates, as determined experimentally, were shown to correlate linearly with the concentration of autoinducer C4-HSL. These findings were used to derive a simple model, wherein a putative, extracellular protein with C4-HSL degrading activity was assumed (putative C4-HSL acylase). The model is based on data for catalytic efficiency of HSL-acylases extracted from literature (k cat/K m), experimentally determined basal C4-HSL production rates (q C4 - HSL (basal)), and two fitted parameters which describe the formation of the putative acylase and is therefore comparatively simple.
    Applied Microbiology and Biotechnology 06/2013; · 3.81 Impact Factor
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    ABSTRACT: Recently, several investigations have been carried out on the in situ bacteria flooding, but the ex situ biosurfactant production and addition to the sand pack as agents for microbial enhanced oil recovery (MEOR) has little been studied. In order to develop suitable technology for ex situ MEOR processes, it is essential to carry out tests about it. Therefore, this work tries to fill the gap. The intention of this study was to investigate whether the rhamnolipid mix could be produced in high enough quantities for enhanced oil recovery in the laboratory scale and prove its potential use as an effective material for field application. In this work, the ability of Pseudomonas aeruginosa MM1011 to grow and produce rhamnolipid on sunflower as sole carbon source under nitrogen limitation was shown. The production of Rha-C10-C10 and Rha2-C10-C10 was confirmed by thin-layer chromatography and high-performance liquid chromatography analysis. The rhamnolipid mixture obtained was able to reduce the surface and interfacial tension of water to 26 and 2 mN/m, respectively. The critical micelle concentration was 120 mg/L. Maximum rhamnolipid production reached to about 0.7 g/L in a shake flask. The yield of rhamnolipid per biomass (Y RL/x ), rhamnolipid per sunflower oil (Y RL/s ), and the biomass per sunflower oil (Y x/s ) for shake flask were obtained about 0.01, 0.0035, and 0.035 g g(-1), respectively. The stability of the rhamnolipid at different salinities, pH and temperature, and also, its emulsifying activity has been investigated. It is an effective surfactant at very low concentrations over a wide range of temperatures, pHs, and salt concentrations, and it also has the ability to emulsify oil, which is essential for enhanced oil recovery. With 120 mg/L rhamnolipid, 27 % of original oil in place was recovered after water flooding from a sand pack. This result not only suggests rhamnolipids as appropriate model biosurfactants for MEOR, but it even shows the potential as a biosurfactant of choice for actual MEOR applications.
    Applied biochemistry and biotechnology 05/2013; · 1.94 Impact Factor
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    ABSTRACT: Alkyl sophorosides, a special type of sophorolipids, can be produced using Candida bombicola cultures with glucose as main carbon source and 2-dodecanol as co-substrate. The dominating component, 2-dodecyl-sophoroside SL-E2-12, was purified via medium pressure liquid chromatography (MPLC) and used as substrate for further enzymatic modifications. Using β-glucuronidase in aqueous media the first modification gave a glycosidic cleavage of the acetyl glucose unit leading to 2-dodecyl-glucoside GL-A2-12. In a subsequent lipase-catalyzed acylation with sebacic acid in toluene this compound was functionalized regioselectively at the primary C-6′ position of glucose. Similar lipase-catalyzed reactions in toluene, but now using SL-E2-12 as acyl acceptor and unusual hydroxyl fatty acids – 3-hydroxy decanoic acid and 17-hydroxy stearic acid – as acyl donors, resulted in mono- and diacylations of primary hydroxyl positions of the sophorose unit (C-6′ and C-6′′) as shown by NMR and MS studies. In physicochemical characterization experiments the new glycoconjugates lowered the surface tension of water from 72 to 27–32 mN/m. Moreover it was observed that the new products inhibit the growth of particular Gram-positive bacteria. Additionally they indicate potential for anti-tumor promoting activity. Practical applications: According to literature data 2-alkyl-sophorosides can be produced using Candida bombicola cultures with yields of more than 20 g/L. Based on this starting material, 2-dodecyl-sophoroside, several regioselective enzymatic modifications were performed. Initially, β-glucuronidase catalysis in aqueous buffer solution gave 2-dodecyl-glucoside which was then successfully acylated at the C-6 position of glucose by lipase catalysis using a common dicarboxylic acid, sebacic acid. The resulting free carboxylic function of the acidic derivative opens up the possibility of achieving additional chemo-enzymatic reactions at this position for conversion, for instance, into polyesters. In addition lipase catalysis in organic solvents of 2-dodecyl-sophoroside allows acylation with unusual hydroxyl fatty acids of microbial origin. Physicochemical studies showed that these new glycoconjugates may be of interest for the cosmetic industry due to moisture conservation of the skin. For practical applications the conditions of the above biocatalytic reactions have been improved and scaled up.
    European Journal of Lipid Science and Technology 04/2013; 115(4). · 2.27 Impact Factor
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    ABSTRACT: Culturing Pseudozyma aphidis on glucose as main carbon source and soybean oil as co-substrate the mannosylerythritol lipids MEL-A and MEL-B were produced. Based on their excellent surface/interfacial active behavior they possess a high potential among all known biosurfactants. The components of a microbial MEL mixture were purified by medium pressure liquid chromatography (MPLC) and were used as substrates for in vitro enzymatic modifications. Lipase-catalyzed acylations of MEL-A and MEL-B with uncommon fatty acids from other microbial glycolipids-3-hydroxydecanoic acid from rhamnolipids and 17-hydroxyoctadecanoic acid from classical sophorolipids-yielded functionalized products at the C-1 position of the erythritol. The novel products were purified by MPLC and their structures elucidated by (1)H and (13)C nuclear magnetic resonance spectroscopy and mass spectrometry. In physicochemical characterization experiments two of the three new glycoconjugates lowered the surface tension of water from 72mNm(-1) to 27-38mNm(-1). Moreover the novel compounds inhibited the growth of gram-positive bacteria and showed a potential for anti-tumor-promoting activity.
    Carbohydrate research 03/2013; 373C:82-88. · 2.03 Impact Factor

Publication Stats

1k Citations
302.89 Total Impact Points

Institutions

  • 2006–2014
    • Karlsruhe Institute of Technology
      • • Institute of Process Engineering in Life Sciences
      • • Chair of Technical Biology
      • • Institute of Food and Biotechnology (IBLT)
      • • Engler Bunte Institute
      Carlsruhe, Baden-Württemberg, Germany
    • University of Cape Town
      • Department of Chemical Engineering
      Kaapstad, Western Cape, South Africa
  • 2013
    • Babol Noshirvani University of Technology
      • Faculty of Chemical Engineering
      Bābol, Mazandaran, Iran
  • 1986–2013
    • Technische Universität Braunschweig
      • • Institute of Biochemistry, Biotechnology and Bioinformatics
      • • Institut für Technische Chemie
      • • Institute of Inorganic and Analytical Chemistry
      Braunschweig, Lower Saxony, Germany
  • 2011
    • Heinrich-Heine-Universität Düsseldorf
      • Institut für Molekulare Enzymtechnologie (IMET)
      Düsseldorf, North Rhine-Westphalia, Germany
  • 2008
    • Technical University of Denmark
      • National Laboratory for Sustainable Energy
      Copenhagen, Capital Region, Denmark
  • 1994–2006
    • Universität Stuttgart
      • • Institute for Biochemical Engineering
      • • Institute of Industrial Genetics
      Stuttgart, Baden-Württemberg, Germany
  • 1998
    • Technische Universität Clausthal
      Bergstadt-Clausthal-Zellerfeld, Lower Saxony, Germany
  • 1995
    • Klinikum Stuttgart
      Stuttgart, Baden-Württemberg, Germany