Naoto Isono

In this study, we developed a method to synthesize sophorose using three enzymes―sucrose phosphorylase from Leuconostoc mesenteroides, 1,2-β-oligoglucan phosphorylase from Enterococcus italicus, and exo β-1,2-glucooligosaccharide sophorohydrolase from Parabacteroides distasonis―in a one-pot reaction, employing inexpensive starting materials. After optimization, a reaction was carried out using 5 mM glucose, 250 mM sucrose, 10 mM inorganic phosphate, and enzyme concentrations of 5 µg/mL sucrose phosphorylase, 20 µg/mL 1,2-β-oligoglucan phosphorylase, and 50 µg/mL exo β-1,2-glucooligosaccharide sophorohydrolase at 30 °C for 48 h, yielding 108 mM sophorose. Following yeast treatment, sophorose was purified by size-exclusion chromatography with a final yield of 45 % based on the amount of sucrose used as the donor substrate.

YcjT is a kojibiose phosphorylase found in Escherichia coli. We found that sucrose was a good acceptor of YcjT in reverse phosphorolysis using β-d-glucose 1-phosphate as a donor. The product was identified as β-d-fructofuranosyl α-d-glucopyranosyl-(1→2)-α-d-glucopyranoside. This sugar was also synthesized from sucrose and maltose using YcjT and maltose phosphorylase and promoted the growth of the probiotic Bifidobacterium breve.