Integrierte enzymatische Synthese und Adsorption von Isomaltose in einem Mehrphasenreaktor

Bohnet, Matthias; Ergezinger, M.; Berensmeier, Sonja; Bucholz, K.

doi:10.1002/cite.200407065

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…12 [125,126]. For example, the synthesis of isomaltose by dextransucrase, using glycosyltransfer from sucrose (substrate) to glucose (acceptor), requires an immediate selective separation of the product in the reactor, because isomaltose can be glucosylated itself, resulting in a sequence of higher oligosacchar-ides.…”

Section: Integrated Process Engineeringmentioning

confidence: 99%

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Highlights in Biocatalysis - Historical Landmarks and Current Trends

Bornscheuer

Buchholz

2005

Eng. Life Sci.

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Biocatalysis has ancient roots, yet it is developing into a key tool for synthesis in a wide range of applications. Important events in the history of enzyme technology from the 19th century onwards are highlighted. Considering the most relevant progress steps, the production of penicillanic acid and the impact of genetic engineering are traced in more detail. Applied biocatalysis has been defined as the application of a biocatalyst to achieve a desired conversion selectively, under controlled, mild conditions in a bioreactor. Biocatalysts are currently used to produce a wide range of products in the fields of food manufacture (such as bread, cheese, beer), fine chemicals (e.g., amino acids, vitamins), and pharmaceuticals (e.g., derivatives of antibiotics). They not only provide access to innovative products and processes, but also meet criteria of sustainability. In organic synthesis, recombinant technologies and biocatalysts have greatly widened the scope of application. Examples of current applications and processes are given. Recent developments and trends are presented as a survey, covering new methods for accessing biodiversity with new enzymes, directed evolution for improving enzymes, designed cells, and integrated downstream processing.

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Section: Integrated Process Engineeringmentioning

confidence: 99%

“…The integrated separation of isomaltose is achieved in the reactor by adsorption on the suspended zeolites (< 50 lm), which are fed to and leave the reactor by the fluid phase, Fig. 12 [125,126].…”

Section: Integrated Process Engineeringmentioning

confidence: 99%

Highlights in Biocatalysis - Historical Landmarks and Current Trends

Bornscheuer

Buchholz

2005

Eng. Life Sci.

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“…The effect of substance transport regarding biocatalysis has to be considered when modeling the complete system especially for experiments with higher amounts of biocatalyst and therefore higher specific activity concentrations. For optimization of the whole process, a suitable method for the complete separation of the zeolite and the reaction mixture has to be analyzed in order to achieve acceptable purities and results after desorption for this pilot process [15].…”

Section: Discussionmentioning

confidence: 99%

Integrated Enzymatic Synthesis and Adsorption of Isomaltose in a Multiphase Fluidized Bed Reactor

Ergezinger

Bohnet

Berensmeier³

et al. 2006

Engineering in Life Sciences

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Dextransucrase catalyzes the formation of dextran, but also of numerous oligosaccharides from sucrose and different acceptors, if appropriate conditions are chosen. A process on a technical scale with immobilized enzyme was established to produce isomaltose, a disaccharide of industrial interest. Isomaltose is also a reactant for dextransucrase and has to be quickly taken out of the reaction solution. This was realized by integrated adsorption of isomaltose on zeolites. In the case of biotransformation the reactor works with a fluidized bed of immobilized enzyme and the in situ separation is realized with a suspension flow of adsorbent. This process was investigated experimentally and theoretically. With a design model consisting of hydrodynamics, kinetics of enzymatic synthesis, and thermodynamics of adsorption, a comparison was made between experimental and calculated data.

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“…One of our motivations was to increase product yields and/or to decrease cosubstrate use (glucose) by the application of co-immobilizates, because this would also improve the performance of our fluidized bed reactor with in situ product removal (FBR-ISPR). Integrated adsorption and synthesis using DS alone was already modeled for this reactor type on a semi-technical scale (Bohnet et al, 2005), yet higher isomaltose or lower cosubstrate concentrations would further enhance the selective product adsorption. Figure 1 outlines the reaction scheme for isomaltose synthesis starting from sucrose.…”

Section: Introductionmentioning

confidence: 99%

Co‐immobilization of dextransucrase and dextranase for the facilitated synthesis of isomalto‐oligosaccharides: Preparation, characterization and modeling

Erhardt

Kügler

Chakravarthula

et al. 2008

Biotech & Bioengineering

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Co-Immobilization of dextransucrase (DS) and dextranase (DN) into calcium alginate includes the co-entrapment of soluble DS and adsorbed DN. DS converts sucrose into dextran, which is the substrate for DN, so that isomalto-oligosaccharides (IMOs) are follow-up products of dextran hydrolysis. The boundary conditions for the successful preparation are investigated with respect to choice of DN adsorbate, surface modifications using blotting agents and optimal enzyme activity ratios. Further, repetitive batch experiments suggest the selection of medium activity ratios for continuous use (0.3 U(DN)U(-1) (DS), e.g.). Product formation at various cosubstrate:substrate concentrations as well as at different DN:DS ratios are discussed. Moreover, the complexity of the bi-enzymatic system can be reduced considering the molar ratios of cosubstrate:substrate (glucose:sucrose). Based on these factors, a mechanistic kinetic model is developed, which distinguishes the corresponding contributions of the two enzymes upon overall product formation. In general, at low glucose:sucrose ratios isomaltose synthesis is featured primarily by DN action. Yet with increasing amounts of glucose both the quantity and quality of DN substrate changes, so that its contribution to product formation decreases in an exponential manner; still the overall product yield continuously increases due to enhanced DS contribution.

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Integrierte enzymatische Synthese und Adsorption von Isomaltose in einem Mehrphasenreaktor

Cited by 12 publications

References 8 publications

Highlights in Biocatalysis - Historical Landmarks and Current Trends

Highlights in Biocatalysis - Historical Landmarks and Current Trends

Integrated Enzymatic Synthesis and Adsorption of Isomaltose in a Multiphase Fluidized Bed Reactor

Co‐immobilization of dextransucrase and dextranase for the facilitated synthesis of isomalto‐oligosaccharides: Preparation, characterization and modeling

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