GLYCOSYLATION OF ALCOHOLS BY a-RHAMNOSYL-b- GLUCOSIDASE IN A CONTINUOUS-FLOW REACTOR

LAURA S. MAZZAFERRO; JAN-MATHIS MÜLLER; ALEXANDER FRIES; MICHAEL MÜLLER; JAVIER D. BRECCIA

Simposio; Biotrans 2017; 2017

The a-rhamnosyl-b-glucosidase from Acremonium sp. DSM 24697 is a diglycosidase with transglycosylation activity.[1] Aliphatic short-chain and phenolic alcohols were shown to be glycosylated by this enzyme.[2] 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 (lmax 280 nm) and its aglycon (hesperetin, lmax 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 the activity of the immobilized enzyme in the reactor.