High performing immobilized Baeyer-Villiger monooxygenase and glucose dehydrogenase for the synthesis of ε-caprolactone derivative

The industrial application of Baeyer-Villiger monooxygenases (BVMOs) is typically hindered by stability and cofactor regeneration considerations. The stability of biocatalysts can be improved by immobilization. The goal of this study was to evaluate the (co)-immobilization of a thermostable cyclohexanone monooxygenase from Thermocrispum municipale (TmCHMO) with a glucose dehydrogenase (GDH) from Thermoplasma acidophilum for NADPH cofactor regeneration.

Both enzymes were immobilized on an amino-functionalized agarose-based support (MANA-agarose). They were applied to the oxidation of 3,3,5-trimethylcyclohexanone for the synthesis of ε-caprolactone derivatives which are precursors of polyesters. The performances of the immobilized biocatalysts were evaluated in reutilization reactions with as many as 15 cycles and compared to the corresponding soluble enzymes. Co-immobilization proved to provide the most efficient biocatalyst with an average conversion of 83% over 15 reutilization cycles leading to a 50-fold increase of the biocatalyst yield compared to the use of soluble enzymes which were applied in a fed-batch strategy.

TmCHMO was immobilized for the first time in this work, with very good retention of the activity throughout reutilization cycles. This immobilized biocatalyst contributes to the application of BVMOs in up-scaled biooxidation processes.