This title appears in the Scientific Report :
2003
Please use the identifier:
http://hdl.handle.net/2128/121 in citations.
Elektrochemische Oxidation von Nukleotidkofaktoren - Charakterisierung und Prozessentwicklung asymmetrischer enzymatischer Katalysesysteme
Elektrochemische Oxidation von Nukleotidkofaktoren - Charakterisierung und Prozessentwicklung asymmetrischer enzymatischer Katalysesysteme
[Fig. 1: Horse liver alcohol dehydrogenase (HLADH) catalyzed oxidation of meso-3,4-dihydroxymethylcyclohexene (meso-DHMC) to (3aR,7aS)-3a,4,7,7a-tetrahydro-3H-isobenzofurane1-one (THIBF-1-one), 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate$^{•-}$) (ABTS$^{•-}$) Fig.2: Glycerol dehydrogenase (GDH...
Saved in:
Personal Name(s): | Schröder, Iris (Corresponding author) |
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Contributing Institute: |
Biotechnologie 2; IBT-2 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2003
|
Physical Description: |
XIV, 232 p. |
Dissertation Note: |
Bonn, Univ., Diss., 2003 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Biotechnologie |
Series Title: |
Berichte des Forschungszentrums Jülich
4064 |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
[Fig. 1: Horse liver alcohol dehydrogenase (HLADH) catalyzed oxidation of meso-3,4-dihydroxymethylcyclohexene (meso-DHMC) to (3aR,7aS)-3a,4,7,7a-tetrahydro-3H-isobenzofurane1-one (THIBF-1-one), 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate$^{•-}$) (ABTS$^{•-}$) Fig.2: Glycerol dehydrogenase (GDH)-catalyzed racemic resolution of (R,S)-1-phenyl-1,2ethanediol,] From the process development point of view, alcohol dehydrogenase ($\textit{ADH}$)-catalyzed oxidations represent a major challenge as they are usually characterized by double product inhibition by both the reduced co-factor and the oxidation product formed in the reaction. This thesis describes a newly developed effective procedure for cofactor regeneration (A, B). Following exhaustive screening for suitable substrates and enzymes an enzyme/substrate pair was chosen that allows two different ways to circumvent inhibition by the oxidation product. Intra-molecular cyclization (Fig. 1) for $\textit{in situ}$ removal of the intermediary product is easier to realize in process development. Moreover, the described procedure opens up synthetic pathways towards diols as intermediate compounds for the pharmaceutical industry as well as toward lactones for flavors and fragrances. When the inhibiting intermediary oxidation product cannot be removed by subsequent chemical reaction but remains in the reaction volume (Fig. 2), a more sophisticated process has to be developed. To solve this problem, a new type of reactor for integrated product extraction was developed, the $\textit{extractive electrochemical enzyme membrane reactor}$ (E$^{3}$MR) which is schematically shown in [Fig. 3: E$^{3}$MR: 1) electrochemical flow cell, 2) pump for aqueous circle (peristaltic pump), 3) extraction module (UF hollow fibre module) 10 kD, 8000 cm$^{2}$ surface area, 4) pump for organic circle ($\textit{iso}$-octane), 5) distillation, 6) pressure compensation vessel. Online data recording not shown] During process development, the single steps of the reaction were characterized and the selectivity of the extraction process as well as enzyme stability as critical process parameters were identified by adaptive process simulation. |