One-pot cascade reaction coupling a microbial glycosyltransferase to sucrose synthase for high-level production of cinnamyl alcohol mono-glucoside

Cinnamyl alcohol mono-glucoside (rosin), one of the important ingredients in Rhodiola rosea, displays many biological activities. The traditional production of rosin is direct extraction, which suffers from limited availability of natural resources. This study developed an efficient method for the product of cinnamyl alcohol mono-glucoside using a one-pot cascade reaction by a microbial glycosyltransferase UGT_BL1 coupled with sucrose synthase (GmSuSy) from Glycine max. By optimizing the conditions of the UGT_BL1-GmSuSy coupled reaction, a high yield of cinnamyl alcohol mono-glucoside could be achieved and it showed good compatibility between the microbial glycosyltransferase UGT_BL1 and sucrose synthase GmSuSy for cinnamyl alcohol mono-glucoside formation and UDPG regeneration. Using a fed-batch strategy, cinnamyl alcohol mono-glucoside could reach a high titer of 9.96 g/L with a conversion of 90.8 % in the one-pot cascade reaction. This study lays a significant foundation for the enzymatic production of rosin using glycosyltransferase and sucrose synthase-coupled cascade reactions.