A quartz crystal microbalance with dissipation monitoring of dehydrogenative copolymerization of coniferyl alcohol and sinapyl alcohol

Dehydrogenation polymers (DHPs) can be prepared from coniferyl alcohol (CA), but not solely from sinapyl alcohol (SA) when catalyzed by horseradish peroxidase (HRP). However, it has been proven that from a mixture of CA and SA, DHP with SA incorporated can be formed even with HRP. Conventional experiments using this mixed monolignol system required large amounts of monolignols and enzymes. The use of a quartz crystal microbalance with dissipation (QCM-D) can overcome this drawback. In this study, the dehydrogenative copolymerization of small amounts of CA/SA mixtures and HRP was performed on a QCM-D to further explore the benefits of this system. The DHPs were successfully formed from mixed monolignols on the QCM-D system, and the incorporation of the SA unit was verified through differences in DHP formation between binary monolignol systems and the corresponding CA-single systems. The formation of DHP in the presence of the polysaccharide matrix was performed at the same reaction scale, and the promotional effect of partially acetylated xylan on DHP formation was observed, especially at high CA ratios. The QCM-D monitoring system will be a valuable tool for analyses under limited substrates and/or enzymes that may be encountered in the future.