Development of a ZnO Nanowire Continuous Flow Microreactor with β-Glucosidase Activity: Characterization and Application for the Glycosylation of Natural Products
Elena Gkantzou, Κaterina Govatsi, Alexandra V. Chatzikonstantinou, Spyros N. Yannopoulos, Haralambos Stamatis
Abstract
Microreactor technology is being increasingly utilized in the field of biocatalysis, offering cost-effectiveness and environmental sustainability. On the other hand, enzyme immobilization on nanomaterials can provide biocatalytic systems with the operational stability demands of an intensified bioprocess. Combining the methodology for ZnO nanowire growth on glass surfaces with enzyme immobilization techniques, we developed a novel continuous-flow microbioreactor system, with β-glucosidase activity. Morphological, spectroscopic, and biocatalytic characterization of the developed enzyme microreactor is presented. The immobilized enzyme exhibited almost 100% remaining hydrolytic activity after 1000 cycles of continuous use and more than 70% residual activity after 24 h of exposure to different organic solvents. The system productivity was enhanced up to 10 times compared to the free enzyme form and 30 times compared to the batch immobilized system. Compared to previous studies in batch reactor systems, the enzyme microbioreactor exhibited a productivity enhancement of 315 and 12 times, respectively, for the continuous glycosylation of the natural compounds perillyl alcohol and tyrosol toward the synthesis of their bioactive glycosylated derivatives. The entire arrangement seems to provide a proper microenvironment for enzyme stabilization, under the scope to broaden the biocatalyst’s potentiality.