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.

Abstractβ-Apiosidase is a rare glycosidase applied in winemaking for flavour enhancement. This enzyme is involved in the release of volatile terpenes by hydrolysis of their odourless glycosidic precursors. It is found as a minor component in commercial pectinase/cellulase preparations. Microbial production of β-apiosidase by two Aspergillus sp. strains was investigated. Apiin-induced production of this extracellular glycosidase was confirmed only during the cultivation of Aspergillus niger CBS 554.65 but the high productivity value reported in the work of Dupin et al. (1992) J. Agric. Food Chem. 40(10): 1886—1891 could not be reproduced. The achieved productivity was by far not satisfactory considering the apiin cost. Commercial enzyme preparations with β-apiosidase side-activity thus remain a better alternative as the enzyme source for biocatalytic applications.

Kojic acid is a fungal metabolite and one of the strongest tyrosinase inhibitors. Its esters are used as lipid-compatible skin whitening components in cosmetic formulations. In this study, lipase PS, lipase AK, Lipolyve AN and pig pancreatic lipase catalyzed the acetylation of kojic acid under selective formation of the same product, kojic 7-acetate. However, the enzymes differed in their regioselectivity when catalyzing the alcoholysis of kojic acid diacetate. While lipase PS and lipase AK produced mixtures of both monoacetate regioisomers (7-acetate and 5-acetate of kojic acid), the pancreatic lipase almost exclusively produced 5-acetate. The enzyme displayed the same regioselectivity in the palmitoylation of kojic acid and in the alcoholysis of kojic acid dipalmitate. Simple reaction engineering with PPL as a catalyst thus provides the complementary monoesters of kojic acid. Kojic 7-acetate, 5-acetate, 7-palmitate and 5-palmitate were prepared with yields after purification of 57.3%, 38.2%, 31.7% and 31.4%, respectively.

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