Enzymatic Synthesis and Structural Characterization of Theanderose through Transfructosylation Reaction Catalyzed by Levansucrase from Bacillus subtilis CECT 39

This work addresses the high-yield and fast enzymatic production of theanderose, a naturally occurring carbohydrate, also known as isomaltosucrose, whose chemical structure determined by NMR is α-d-glucopyranosyl-(1 → 6)-α-d-glucopyranosyl-(1 → 2)-β-d-fructofuranose. The ability of isomaltose to act as an acceptor in the Bacillus subtilis CECT 39 levansucrase-catalyzed transfructosylation reaction to efficiently produce theanderose in the presence of sucrose as a donor is described by using four different sucrose:isomaltose concentration ratios. The maximum theanderose concentration ranged from 122.4 to 130.4 g L^–1, was obtained after only 1 h and at a moderate temperature (37 °C), leading to high productivity (109.7–130.4 g L^–1h^–1) and yield (up to 37.3%) values. The enzymatic synthesis was highly regiospecific, since no other detectable acceptor reaction products were formed. The development of efficient and cost-effective procedures for the biosynthesis of unexplored but appealing oligosaccharides as potential sweeteners, such as theanderose, could help to expand its potential applications which are currently limited by their low availability.