CHARACTERIZATION AND APPLICATION OF TANNASE PRODUCED BY ASPERGILLUS NIGER ITCC 6514.07 ON POMEGRANATE RIND

Extracellular tannase and gallic acid were produced optimally under submerged fermentation at 37 degrees C, 72 h, pH 5.0, 10 %(v/v) inoculum and 4 %(w/v) of the agroresidue pomegranate rind (PR) powder by an Aspergillus niger isolate. Tannic acid (1 %) stimulated the enzyme production by 245.9 % while with 0.5 % glucose, increase was marginal. Tannase production was inhibited by gallic acid and nitrogen sources such as NH4NO3, NH4Cl, KNO3, asparatic acid, urea and EDTA. The partially purified enzyme showed temperature and pH optima of 35 degrees C and 6.2 respectively which shifted to 40 degrees C and 5.8 on immobilization in alginate beads. Activity of the enzyme was inhibited by Zn+2, Ca+, Mn+2, Mg+2, Ba+2 and Ag+. The immobilized enzyme removed 68.8 % tannin from juice of aonla/myrobalan (Phyllanthus emblica), a tropical fruit, rich in vitamin C and other essential nutrients. The enzymatic treatment of the juice with minimum reduction in vitamin C is encouraging as non enzymatic treatments of myrobalan juice results in vitamin C removal.