Isolation, Purification and Characterization of β-Glucosidase from Cassava Roots

The isolation, purification and enzymatic properties of β-glucosidase from cassava roots were studied. The crude enzyme extract was obtained from cassava roots with buffer solution, and the activity of crude enzyme was 9.37 U/g cassava dry weight. Purified by acetone precipitation, ion exchange chromatography and gel filtration chromatography, β-glucosidase activity was 1.14 U/g cassava dry weight, purified β-glucosidase purity increased by 14.62 times, the total activity recovery was 12.14%, the molecular weight of β-glucosidase was about 70 kDa. The K_m and V_max of the enzyme were 3.60 mmol/L and 12.36 µmol/(min·mg protein) respectively. The optimum pH was 7.0, and it was stable when the pH was between 6.0 and 8.0. It had good stability within 40 ℃, and 81.78% enzyme activity remained after 30 days at 4 ℃. Mn²⁺ and K⁺ promoted the enzyme to a certain extent. Al³⁺, Cu²⁺, Mg²⁺, Zn²⁺, Ca²⁺, Ba²⁺, Na⁺, urea and SDS had no significant effect on the enzyme activity (P>0.05). Fe³⁺, Fe²⁺, Ag⁺ and EDTA all inhibited the enzyme activity to varying degrees, among which Ag⁺ had the strongest inhibitory effect. The results can provide theoretical basis for the application of β-glucosidase in cassava roots in the future.