Enzymatic fructosylation of organic acceptors other than saccharides brings new possibilities to synthesize molecules that do not exist in nature. The introduction of fructosyl moiety may lead to glycosides possessing enhanced physicochemical and bioactive properties which could be useful in the pharmaceutical and cosmetic industry. In this work, the regioselective synthesis of tyrosol β-d-fructofuranoside (TF) catalyzed by β-fructofuranosidase is investigated. In the first step, 32 commercial enzyme preparations are screened for fructoside-hydrolyzing activity. The most active preparations are subsequently examined for fructofuranosyl transfer from sucrose to tyrosol. The best candidate, Novozym 188, is chosen to study the effect of reaction conditions on the product formation in a batch reactor. The effects of substrate concentration, temperature, pH, time, and enzyme dosage on the concentration of TF produced are studied using the design of experiments methodology. The maximal product concentration of 3.8 g L-1 is achieved for the sucrose concentration of 1.5 m, tyrosol concentration of 29 g L-1 , temperature of 41 °C, and pH 5.1. Besides the main transfructosylation reaction between sucrose and tyrosol, several side reactions take place. A reaction network includes also the formation of fructooligosaccharides and the hydrolysis of sucrose and all reaction products.
Keywords: fructofuranosidase; transfructosylation; tyrosol glycoside; tyrosol β-d-fructofuranoside; β-biocatalyst.
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