Surface-Initiated Dehydrogenative Polymerization ofMonolignols: A Quartz Crystal Microbalance with Dissipation Monitoringand Atomic Force Microscopy Study.

This work highlights a real-timeand label-free method to monitorthe dehydrogenative polymerization of monolignols initiated by horseradishperoxidase (HRP) physically immobilized on surfaces using a quartzcrystal microbalance with dissipation monitoring (QCM-D). The dehydrogenativepolymer (DHP) films are expected to provide good model substratesfor studying ligninolytic enzymes. The HRP was adsorbed onto goldor silica surfaces or onto and within porous desulfated nanocrystallinecellulose films from an aqueous solution. Surface-immobilized HRPretained its activity and selectivity for monolignols as coniferyland p-coumaryl alcohol underwent dehydrogenativepolymerization in the presence of hydrogen peroxide, whereas sinapylalcohol polymerization required the addition of a nucleophile. Themorphologies of the DHP layers on the surfaces were investigated viaatomic force microscopy (AFM). Data from QCM-D and AFM showed thatthe surface-immobilized HRP-initiated dehydrogenative polymerizationof monolignols was greatly affected by the support surface, monolignolconcentration, hydrogen peroxide concentration, and temperature. [ABSTRACT FROM AUTHOR]