Simultaneous production of 1,3-dihydroxyacetone and xylitol from glycerol and xylose using a nanoparticle-supported multi-enzyme system with in situ cofactor regeneration.

Cofactor-dependent biotransformations often require consumption of a secondary substrate for cofactor regeneration. Alternatively, two synthetic reactions may be coupled together through cofactor regeneration cycles. Simultaneous production of value-added products from glycerol and xylose was realized in this work through an enzymatic NAD(H) regeneration cycle involving two enzymes. Glycerol dehydrogenase (GDH) catalyzed the production of 1,3-dihydroxyacetone (DHA) from glycerol, while xylose reductase (XR) enabled the reduction of xylose to xylitol using the protons released from glycerol. Both enzymes were immobilized with P(MMA-EDMA-MAA) nanoparticles. Interestingly, the immobilized multi-enzyme system showed much improved productivity and stability as compared to native enzymes, such that the total turnover number (TTN) reached 82 for cofactor regeneration while the yield reached 160g/g-immobilized GDH for DHA production.