Plant extract assisted extracellular tannase production by Aspergillus Sp MIK23

An extracellular tannase (E.C. 3.1.1.20) producing fungal strain was isolated from soil and identified as Aspergillus sp MIK23. Out of various plant extracts, Terminalia chebula powder (TCP) in the optimized medium enhanced enzyme production. Maximum yield of tannase (3 IU ml^-1) was obtained with glucose (10 g/L), urea (2 g/L), and yeast extract (2.5 g/L) when inoculated with 10% inoculum in 48 h. An initial medium at pH 6.0 and a cultivation temperature of 37°C was found to be optimum for enzyme production. Metal ions Mg²⁺, Zn²⁺, Ca²⁺, Cu²⁺ and Cd²⁺ did not improve enzyme activity, whereas, Ca²⁺, Fe²⁺ and Hg²⁺ repressed enzyme activity. The enzyme was purified using ammonium sulfate precipitation followed by Q-sepharose ion-exchange chromatography. The enzyme was purified to 42-fold with an overall recovery of 20. The pH and temperature optima of the purified tannase were found to be 7.0 and 37°C, respectively.