The Tannase from red yeast Rhodotorula glutinis : purification and characterization

The tannase enzyme was successfully purified to homogeneity from the culture broth of red yeast strain Rhodotorula glutinis DB2 in a three-tandem step involving ultrafiltration (5 kDa and 100 kDa systems), Sephadex G-200 gel filtration chromatography, and DEAE Sepharose CL-4B anion exchange chromatography. The purified tannase appeared to be homogeneous on sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE). The purified tannase had a specific activity of 3.33 U mg−1, with a 1.3% recovery and overall purification of 302-fold. The molecular mass of the tannase estimated by SDS-PAGE was about 73 kDa. The tannase had an optimum pH of 6.0 and an optimum temperature of 40 °C. The most stable pH was 7.0, and the enzyme was stable up to 40 °C. One mmol L−1 of Fe3+, Sr2+, Na+, and Pb2+ were found to promote tannase activity, whilst 1.0 mmol L−1 of Ba2+, Ca2+, Mg2+, Zn2+, Hg+, Ag+, Co2+, Fe2+, Mn2+, Cu2+, Cd2+, Al3+, K+, Ni2+, and Li+ inhibited tannase activity.