Biocatalytic β-glucosylation/β-galactosylation of Rebaudioside C by glycosynthases

• Published in: Food materials research Vol. 4; no. 1; pp. 1 - 6
• Main Authors: Yu, Ye-Yang, Zhang, Si-Yu, Sun, Jia-Hui, Li, Yu-Yang, Zhang, Yao-Yao, Lu, Ai-Min, Liu, Li, Voglmeir, Josef
• Format: Journal Article
• Language: English
• Published: Maximum Academic Press 2024
• Subjects: glycosyl fluoride; glycosylation; glycosynthase; protein engineering; rebaudioside c
• ISSN: 2771-4683; 2771-4683
• DOI: 10.48130/fmr-0023-0043

Extracts of Stevia rebaudiana Bertoni plant leaves contain a mixture of diterpene glycosides which possess high sweetness and are used as non-caloric sweeteners in foods and beverages. One of the most abundant of these steviol glycosides is Rebaudioside C (Reb C), which bears one esterified β-D-glucose and one glycosidically linked α-L-rhamnosyl-(1→2)-[β-D-glucosyl-(1→4)]-D-glucose trisaccharide. In this work, we isolated Reb C from commercial Stevia extracts using an orthogonal normal-phase × reversed-phase purification strategy. We then demonstrated that Reb C could be used as a donor substrate for enzymatic trans glycosylation reactions using chemically synthesized 1-deoxy-1-fluoro-D-glucose and 1-deoxy-1-fluoro-D-galactose donors and two engineered glycosynthases derived from Agrobacterium and Streptomyces β-glycosidases. This chemoenzymatic glucosylation/galactosylation strategy may be of use to extend the current repertoire of steviol glycosides analogues for analysis or the sensory evaluation of these novel steviol glycosides.