Production of Lactosucrose from Sucrose and Lactose by a Levansucrase from Zymomonas mobilis

Abstract

Lactosucrose (4(G)-beta-D-galactosylsucrose) is in oligosaccharide consisting of galactose, glucose, and fructose. In this study we prepared lactosucrose from lactose and sucrose using a levansucrase derived from Zymomonas mobilis. Optimum conditions for lactosucrose formation were 23 degrees C, pH 7.0, 18.0% (w/v) lactose monohydrate, and 18% (w/v) sucrose as substrates, and 1 unit of enzyme/ml of reaction mixture. Under these conditions, the lactosucrose conversion efficiency was 28.5%. The product was purified and confirmed to he O-beta-D-galactopyranosyl-(1 -> 4)-O-beta-D-glucopyranosyl-(1 -> 2)-beta-D-fructofuranoside, or lactosucrose. A mixed-enzyme system containing a levansucrase and a glucose oxidase was applied in order to increase the efficiency of lactose and sucrose conversion to lactosucrose, which rose to 43.2% as a result.