Conversion of Glycerol to Dihydroxyacetone Using Highly Stabilized Glycerol Dehydrogenase

Biodiesel industry generates glycerol as a by-product, and the conversion of glycerol to useful products is an important issue. An enzyme, called glycerol dehydrogenase (GDH), can catalyze the conversion of glycerol to dihydroxyacetone (DHA), which is used as a tanning agent in cosmetics and a lot more expensive than glycerol. In this study, GDH was adsorbed (ADS) into magnetically-separable mesoporous silica with 38 nm mesocellular pores connected via 18 nm window mesopores (ADS), and further crosslinked via a simple glutaraldehyde treatment to prepare ‘nanoscale enzyme reactors’ of GDH (NER). When the stabilities of free and immobilized GDHs were checked under shaking (200 rpm), the residual activities of free GDH and ADS could not be measured due to the inactivation of GDH after 8 days and 22 days, respectively, while NER maintained 64% of initial activity even after 24-day incubation. Magnetically-separable NER maintained 39% of initial activity after seven cycles of repeated uses while the residual activity of ADS dropped to 13% of initial activity only after two recycled uses.