Presse-Information

Press release ¤ Information de presse

May 14, 2006

DECHEMA Student Awards 2006

Six graduates distinguished for efficient completion of their studies

This year the DECHEMA Student Awards will be presented for the thirteenth time in succession to graduates in technical chemistry, chemical process engineering / chemical engineering, and biotechnology who have distinguished themselves by their outstanding academic performance achieved in a remarkably short period of study.

In accordance with the decision of the DECHEMA Education Committee, the DECHEMA Student Awards 2006 will be presented to six graduates during the Opening Session of ACHEMA on 14 May 2006 in the CongressCenter of Messe Frankfurt:

In Technical Chemistry
· Dipl.-Chem. Julia Lembrecht, University of Rostock
· Dipl.-Chem. Carsten Streb, Technical University of Kaiserslautern

In Chemical Process Engineering / Chemical Engineering
· Dipl.-Ing. Johannes Kiefer, University of Erlangen-Nürnberg
· Dipl.-Ing. Holger Maier, Technical University of Darmstadt

In Biotechnology
· Dipl.-Biotechn. Martin Rütze, University of Münster
· Dipl.-Biochem. Cindy Schulenburg, University of Halle/Wittenberg

The DECHEMA Student Awards have been awarded annually since 1994. The aim is to increase the efficiency of students at German universities. Hitherto the most awards have been won by students from the University of Halle/Wittenberg, followed by RWTH Aachen, the University of Karlsruhe (TH) and the Technical Universities of Berlin, Darmstadt and Munich.

Photos of the award ceremony can be obtained on request from:
DECHEMA e.V., Öffentlichkeitsarbeit, Theodor-Heuss-Allee 25,
60486 Frankfurt/M, Tel.: 069/7564-267 or e-mail:
and are also available for download on the Internet at www.dechema.de, Presse.


Abstracts of the diploma theses of the award-winners:

Enzyme-catalysed reduction of prochiral ketones to (R)-alcohols by means of alcohol dehydrogenase from Lactobacillus brevis – conversion into 2-phase systems with unconventional solvents

Julia Lembrecht, University of Rostock
Field: Technical Chemistry

In the past few years the optical purity of fine chemicals and pharma precursors, and thus the production of optically pure compounds, has become increasingly more important. Here, enzymes represent a promising alternative to the conventional transition metal catalysis.

Julia Lembrecht investigated the enzymatic reduction of poorly water-soluble ketones to optically pure (R)-alcohols. Using various 2-phase systems she was able to achieve an integrated product isolation. To understand the system better in terms of kinetic (rate) and thermodynamic (end conversion) parameters, she determined the influence of different reaction parameters, such as various solvents or the ratio of volume or co-substrate to substrate, using the model reaction of acetophenone to (R)-1-phenylethanol in order to be able to predict the final conversion.

Julia Lembrecht succeeded in predicting the final conversion, backing it up statistically. She even transferred the calculation basis to derivates of acetophenone with electronegative substituents, achieving good results here, too.

Properties and catalytic activity of chloroperoxidase immobilized on SBA-15

Carsten Streb, Technical University of Kaiserslautern
Field: Technical Chemistry

Carsten Streb’s diploma thesis focused on the development of an enzyme-based, environmentally friendly, re-usable catalyst for the stereoselective oxidation of organic molecules. For this purpose he anchored the versatile enzyme chloroperoxidase both by physical adsorption and by chemical bonding on the porous support material SBA-15. In several test series Carsten Streb was able to demonstrate that the solid thus produced can be applied over a wide pH range and that it is less sensitive to chemical impacts than the enzyme itself. It can easily be separated from the reaction solution and be applied repeatedly.

Simultaneous determination of temperature and species concentrations by applying combined laser-Raman techniques

Johannes Kiefer, University of Erlangen-Nürnberg
Field: Chemical Process Engineering / Chemical Engineering

In process engineering the temperature and the concentration of the species involved in a process often have to be determined, e.g. in the monitoring and control of processes. In research the determination of the two parameters often makes a substantial contribution to our understanding of chemical reactions and thermodynamic processes. Here the simultaneous determination of the parameters is crucial.

In his diploma thesis Johannes Kiefer developed a very accurate, locally and chronologically high-resolution laser-optical measurement technique that for the first time permits such a simultaneous determination of the gas phase temperature and the concentration of all majority species. He achieved this by modifying the linear Raman spectroscopy and the non-linear coherent anti-Stokes Raman spectroscopy. Johannes Kiefer tested the technique by investigating an injection process of liquid gas.

An alternative technique that he developed shows great potential for application in systems that are difficult to access, such as in motors for the simultaneous determination of the temperature and rate of waste gas return and in chemical reformers for the investigation of the processes taking place there.

Molecular dynamics investigations of phase boundaries in systems composed of two-centre Lennard-Jones particles

Holger Maier, Technical University of Darmstadt
Field: Chemical Process Engineering / Chemical Engineering

Heterogeneity in the phase boundary area causes the material, pulse and energy transport and also chemical reactions at phase boundaries to proceed under different conditions than in the bulk phase. The concrete mechanisms by which this heterogeneity impacts the processes are not yet known. An understanding of the mechanisms should help to explain phenomena, such as Marangoni convection or the boundary viscosity, which can affect mass transfer in process technical separation processes (liquid-liquid extraction or rectification).

In his diploma thesis Holger Maier investigated to what extent the structure of a substance varies with heterogeneity in the phase boundary and thus influences processes in the phase boundary area. To this end he simulated a liquid-liquid phase boundary system, exemplified by nitrogen ethane, at molecular level using the two-centre Lennard-Jones model and determined the mean molecular orientation at the phase boundary and in the bulk phases and also the thickness of the phase boundaries by means of statistical mechanics.

In doing so Holger Maier discovered that thermal state values, such as particle elongation, have no influence on phase boundary structure, but that at the liquid-liquid phase boundary other effects, for example capillary waves and the relative arrangement of molecules, dominate.

Molecular organisation of the c-raf promoter of the rat

Martin Rütze, University of Münster
Field: Biotechnology

The serin/threonine kinase c-raf has important functions concerning regulation of cell proliferation and apoptosis and in many tumours, above all in epithelial tumours, it is overactivated. This observation has given rise to numerous attempts to use inhibition of c-raf therapeutically; of these, however, hitherto none has been applied to the expression of the protein. For this reason the sequence of the c-raf promoter of the rat was cloned and sequenced by Prof. Dr. Borlak and Prof. Dr. Jenke from a genomic library. In a previous work it was shown that the aryl hydrocarbon (Ah) receptor binds this promoter.

In his diploma thesis Martin Rütze used bioinformatic methods to look for binding places of further transcription factors, verifying them by means of electromobility shift assays. He demonstrated that the factors NF-1, AP-4 and BARBIE bind, confirming this by competition with published gene probes.

In addition he investigated whether various Ah receptor antagonists can deactivate the c-raf promoter. For example the analgesic, salicylamide, prevented the receptor from binding the c-raf probes. Inhibition of the gene or protein expression could only be shown in one-off experiments. Thus the results substantiate the assumption that intervention in a signal transmission mediated by c-raf can also take place by intercepting the Ah receptor.

Stability and folding of onconase and genetically determined variants

Cindy Schulenburg, University of Halle/Wittenberg
Field: Biotechnology

Onconase® (Alfacell Corporation, Bloomfield, USA) is a ribonuclease, found in the ovocytes and the early embryo stages of the Northern Leopard frog (Rana Pipiens). The enzyme consists of 104 amino acids and thus represents the smallest member of the RNase A superfamily. Onconase manifests a sequence homology of 30% to the main representative of this superfamily, RNase A. Onconase is, however, evidently more stable than RNase A. Compared to RNase A, onconase has structural characteristics which are probably the cause of its high stability.

In order to investigate whether and what influence these structural characteristics have on the stability and folding of onconase Cindy Schulenburg studied genetically produced enzyme variants with mutations in the corresponding regions. She showed that all variants were thermodynamically less stable than the wild type. In kinetic investigations she discovered that the variants fold back identically to the wild-type protein, but that they unfold quicker, which explains the reduced stability. Furthermore Cindy Schulenburg studied the sequence of the fold-back reaction and was able to find proof of a three-phase mechanism with two intermediates.

 

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