Partial purification of tannase enzyme produced by Bacillus licheniformis isolated from local soils

Tannase is an enzyme that causes hydrolysis of a group of tannins (gallo-tannins) to gallic acid and glucose. This enzyme is of importance due to its numerous applications in many fields, such as in the food industry by enhancing tea and coffee flavour and improving the quality of fruit juices rich in tannins. Gallic acid is applied in the drug industry, and production of antioxidants is used in the oil industry. In this study, Tannase was produced by locally isolated Bacillus licheniformis using spent tea as substrate using submerged fermentation. The crude enzyme was extracted and centrifuged at 10,000 rpm for 10 minutes at 15˚C, and a partial purification was carried out using precipitation by ammonium sulphate 80%, then Sephadex G-75 gel filtration column (2.2×1.8 cm) with acetate buffered solution (0.2 M, pH 5.0) at a flow rate of 60 ml/h up to 3.16 fold with a specific activity reaching 0.931 IU/mg(unit of enzyme per mg). The molecular weight of the purified enzyme was determined to be 48 kDa using SDS-PAGE. Thus, the purification step is a step before applying the pure enzyme in the food industry.