Enzymic synthesis of salidroside: Purification and characterization of salidrosidase from Aspergillas niger

An enzyme synthesising salidroside with p-tyrosol and β-d-glucose was isolated from Aspergillas niger, purified and characterized in this paper. After (NH4)2SO4 precipitation and ion exchange chromatography, the enzyme was purified to one band in SDS-polyacrylamide gel electrophoresis, and its molecular weight was about 84.6 kDa. The optimum temperature of the enzyme was 45 °C, and the optimum pH was 5.0. The enzyme was stable at less than 55 °C and pH 4.5–6.0. The enzyme catalyzed p-tyrosol and β-d-glucose to form salidroside in the concentrations of 1.5% p-tyrosol and 6% β-d-glucose. The yield of salidroside was about 10%.