Enzymatic synthesis of polyglucosylfructosides from sucrose alone by a novel α-glucosidase isolated from the digestive juice of Archachatina ventricosa (Achatinideae)

A novel α-glucosidase was purified from the digestive juice of the snail Archachatina ventricosa using Q Sepharose Fast Flow ion-exchange chromatography and preparative polyacrylamide gel electrophoresis. The enzyme has a molecular weight of 138 kDa by gel filtration and 66 kDa on SDS-PAGE, which corresponds to a homodimeric structure. The pH and temperature optima of sucrose hydrolytic activity are 5.5 and 45 °C, respectively. The enzyme is active on sucrose, pNP α-d-glucopyranoside, maltose and is unable to hydrolyse raffinose, cellobiose and polymers such as amylose, inulin and cellulose. We investigate the transglycosylation potential of this enzyme using sucrose as single glucosyle donor and acceptor substrate in order to access specific features which are of interest from a biotechnological point of view (i.e. oligosaccharides synthesis). The enzyme (1 U/ml of hydrolytic activity) incubated with sucrose (1.5 M) exhibits transglycosylation activity producing polyglucosylfructosides and disaccharides in lesser amount. About 60% of the initial sucrose was consumed after 72 h of incubation at 35 °C.