Yeast β‒fructosidase-catalyzed synthesis of tyrosol fructoside in mono- and biphasic organic–aqueous systems

Tyrosol and its glycosides offer cell protection from oxidative stress and various health benefits. In this study, Saccharomyces cerevisiae β ‒fructosidase potential for synthesizing tyrosol fructoside in mono- and biphasic solvent systems was assessed using 1.5 M sucrose, 10 g/L or 25 g/L tyrosol, at pH 6 and 40°C. Monophasic organic–water systems were designed with nine organic solvents (log P ranging from -1.35 to 0.5). Initial rates of sucrose hydrolysis, tyrosol and sucrose transfructosylation and tyrosol fructoside yields were evaluated. The hydrolytic activity increased with the addition of 5–15% organic solvents, revealing no clear correlation between the log P and sucrose hydrolysis rate. Simultaneously, transfructosylation reaction rates decreased, despite lower water activity. Notably, the effect of log P on tyrosol transfructosylation was observed in 70:30 (v/v) aqueous/organic biphasic systems. Differences in tyrosol fructoside synthesis in six biphasic reaction media were attributed to the unequal solubility of tyrosol in the organic phase, impacting its availability for the enzyme. Product yields were either similar to or lower than those in aqueous media, with no tyrosol fructoside partitioning into the organic phase, thus no effect of product stripping could be observed. Consequently, transfructosylation of tyrosol proves most effective in organic solvent-free media.