Project Details
Projekt
Integration of reaction and product separation for tri-enzymatic catalyzed syntheses of high-value oligo-saccharides from sucrose
Subject Area
Chemical and Thermal Process Engineering
Biological Process Engineering
Biological Process Engineering
Term
from 2009 to 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 123310015
In this project, a trienzymatic production system for the conversion of sucrose to laminaribiose by means of sucrose phosphorylase, glucose isomerase and laminaribiose phosphorylase is investigated. Besides the production of the value product laminaribiose, this complex reaction system is also brilliantly suitable as a model system for basic research on a multienzymatic process with reaction integrated adsorption.In the first project phase, the individual reaction und separation contributions were characterized. As a first step, immobilization was realized as a 3-bead-concept. A chitosan-phosphate-matrix was used as immobilization matrix. BEA-zeolites have proven especially suitable adsorbents for the reaction product. Based on these individual contributions, a first simulation model of the trienzymatic reaction with reaction integrated adsorption was established.In the second project phase the applicability of further polysaccharides for the optimization of the enzyme immobilization will be investigated. Besides the 3-bead-concept, research also addresses 2-bead-concepts (co-immobilization of two enzymes within one bead, with random distribution as well as a core-shell-design and a second bead for the third enzyme), and a 1-bead-concept for all three enzymes, again with random distribution or core-shell-design. The reaction kinetics model of laminaribiose phosphorylase will be extended to the production of higher oligomers, in order to establish a more comprehensive model.Based on typical mixture compositions of all involved reactants, ad- and desorption experiments on multiple components systems will be carried out. Additionally, the effect of high concentrations of the reactants as well as of the polysaccharides themselves on diffusion properties of the intermediates will be studied.To keep the production costs low, the immobilized biocatalyst must be active in the process as long as possible. Furthermore the biocatalyst should be storable and reusable. For this purpose, mechanical stability, half-life of the enzymatic activity of the immobilizates as well as their storability will be studied.For the production of laminaribiose with an immobilized trienzymatic system, the kinetics will be investigated with a stirred tank reactor. Based on the results, the influence of reaction integrated adsorption will be studied. Reaction kinetics of the isolated systems, the combined overall system, mass transport in the enzyme carrier as well as adsorption kinetics and equilibria will be modeled. These new insights contribute to the operation and further optimization of a pilot reactor. This reactor consists of a fluidized bed with an external pump-around, the reaction volume can be varied between 5 - 15 L.Based on the experimental data for the different concepts and the modeling results, general design guidelines for the design of multienzymatic systems with immobilized enzymes and an adsorption as ISPR step will be derived.
DFG Programme
Research Grants
