Glycosylation of alcohols by α-rhamnosyl-β-glucosidase in a continuous-flow reactor

MAZZAFERRO LS; BRECCIA JD

Congreso; BIOTRANS2017; 2017

GLYCOSYLATION OF ALCOHOLS BY a-RHAMNOSYL-b-GLUCOSIDASE IN A CONTINUOUS-FLOW REACTORLaura S. Mazzaferro, Jan-Mathis Müller, Alexander Fries, Michael Müller, Javier D. BrecciaInstitut für Pharmazeutische Wissenschaften, Albert-Ludwigs-Universität Freiburg, Freiburg, GermanyINCITAP-CONICET, FCEyN-Universidad Nacional de La Pampa, Santa Rosa, ArgentinaThe a-rhamnosyl-b-glucosidase from Acremonium sp. DSM 24697 is a diglycosidase withtransglycosylation activity [1][2]. Aliphatic short-chain and phenolic alcohols were shown to be glycosylated by this enzyme. In this work, the flavonoid hesperidin and the polyalcohols ethylene glycol and glycerol were used as sugar donor and acceptors, respectively (Fig. 1). In batch reactions, a conversion higher than 90% was obtained with both acceptors, rendering the monoglycosylated products rutinosyl-ethylene glycol and rutinosyl-glycerol. Further, a continuous-flow reactor was designed. The enzyme was covalently immobilized on chitosan beads and loaded onto a column. The outcome of the reaction was monitored by UV-Vis spectrometry (DAD-detector) using a recirculation quartz cuvette. The differential UV-visible absorption of hesperidin (280 nm) and its aglycon (hesperetin, 323 nm) at pH 8, together with the lack of absorption of glycerol in this range, allowed the on-line monitoring of the reaction. An increase of the absorption at 323 nm therefore indicated an increase in hesperetin concentration of the solution, demonstrating theactivity of the immobilized enzyme in the reactor. Figure 1. a-Rhamnosyl-b-glucosidase-catalyzed transglycosylation[1] Mazzaferro, L.; Piñuel, L.; Minig, M.; Breccia, J. D. Arch. Microbiol. 2010, 192, 383-393.[2] Mazzaferro, L. S., Piñuel, L.; Erra-Balsells, R.; Giudicessi, S. L.; Breccia, J.D. Carbohydr. Res. 2012, 347,69-75.