Workpackage 4: Transaminase tandem reactions employing metal and organo catalysts

Workpackage Leader: Prof. Dr. Harald Gröger
Lead beneficiary: University Bielefeld
Participating Partners: Entrechem, DSM, KTH, TU Graz
Start month: 7 End month: 42

Description of work and role of partners

One-pot C–C coupling and transamination: For cascade 6, a careful analysis of parameters limiting compatibility of the second step of the reaction will be performed. Both, the chemical and the enzymatic steps will be optimized in close collaboration. The immobilization of the palladium catalyst will be investigated to facilitate its reuse and easy removal from the reaction medium. The efficiency of the enzymatic step will be addressed especially by means of protein engineering. The primary aim is to increase activity towards the relatively bulky ketone substrates in order to obtain high space-time yields, and to improve stability or to avoid inhibition in the presence of reaction components necessary in the metal catalyzed reaction.

The capsaicin synthesis will be optimized and up-scaled for industrial implementation. Different one-pot / cascade reactions developed at laboratory scale will be evaluated concerning suitability for upscaling based on criteria as economic and ecologic efficiency after first optimization experiments. After a decision for one of the options A-C, an in depth analysis will be carried out to decipher the bottlenecks for further optimization. Detailed kinetics of the single catalysts will be elucidated, and the whole process will be modeled using a MatLab script or the freely available Cytoscape or Celldesigner program. As many parameters will be modelled, such as activity, substrate and product inhibition, and enzyme inactivation, different scenarios for an improved process can be suggested in silico and subsequently, a few, meaningful experiments for reaction and protein engineering will be conducted. In the second project phase at Enzymicals, the optimized reaction will be transferred to a scale of up to 100 l, where the main focus lies on technical optimization of enzyme production on large scale and downstream processing, catalyst immobilization and reusability for increasing cost efficiency. The knowledge obtained from mathematic modeling will facilitate upscaling of the cascades developed in the other projects.

Objectives

    1.) Establishment of Pd –catalyzed reactions with transaminase catalysis as a new synthetic concept.
    2.) Up-scaling of an established cascade (TRL4) for capsaicine synthesis.
    3.) Protein engineering of transaminases to increase activity and catalyst compatibility.

The Biocascades Project is a joint collaboration among the following university and industrial partners