Biotransformation of sucrose into hexyl-α-d-glucopyranoside and -polyglucosides by whole cells of Microbacterium paraoxydans

Abstract

Objective: To determine the transglycosylation activity of cell-bound enzymes from Microbacterium paraoxydans to catalyze the synthesis of hexyl-α-d-glucoside (HG) and -polyglucosides using sucrose as a glycosyl donor. Results: Maximum HG yield (14.8 %) was achieved at 0.96 water activity in 12 h with sucrose at 0.5 M with lyophilized cells (equivalent to 8 IU α-glucosidase activity). The synthesized alkyl-glucosides and-polyglucosides were characterized by ESI-MS. Structural elucidation of the main product (purified by solid phase chromatography) was done by HSQC (2D NMR) which was confirmed as 1-hexyl-α-d-glucopyranoside. The synthesis was scaled up in a fed-batch reactor, with continuous feeding of whole cells every 6 h and a total yield of ~44 % was obtained for hexyl-glucoside and -polyglucosides under the optimized conditions. Conclusion: Synthesis of HG, hexyl di- and tri-glucosides has been achieved using a novel method.