Immobilizing Systems Biocatalysis for the Selective Oxidation of Glycerol Coupled to In Situ Cofactor Recycling and Hydrogen Peroxide Elimination

Abstract

The combination of three different enzymes immobilized rationally on the same heterofunctional carrier allowed the selective oxidation of glycerol to 1,3-dihydroxyacetone (DHA) coupled to in situ redox-cofactor recycling and H2O2 elimination. In this cascade, engineered glycerol dehydrogenase with reduced product inhibition oxidized glycerol selectively to DHA with the concomitant reduction of NAD+ to NADH. NADH oxidase regenerated the NAD+ pool by oxidizing NADH to NAD+ to form H2O2 as the byproduct. Finally, catalase eliminated H2O2 to yield water and O2 as innocuous products, which avoided the spontaneous DHA oxidation triggered by H2O2. The co-immobilization of the three enzymes on the same porous carrier allowed the in situ recycling and disproportionation of the redox cofactor and H2O2, respectively, to produce up to 9.5 mM DHA, which is 18- and 6-fold higher than glycerol dehydrogenase itself and a soluble multienzyme system, respectively.