Pomegranate peels: A novel ago-residue for tannate production by gamma irradiated aspergillus versicolor under solid state fermentation

Pomegranate peels were tested as a substrate for the production of tannate and gallic acid (GA) under solid state fermentation (SSF) using Aspergillus versicolor-g3B (highly potent gamma irradiated tannate producer isolate). The fungal strain was grown on the substrate without any pre-treatment. Different parameters for maximum production of tannate by this strain under SSF method were optimized. The maximum tannate yield (12.45μg-1ds) and GA (94%) were obtained when SSF was carried out at ph 5.0, 30 degree C, 60% initial substrate moisture, 20% inoculum size, 3% tannic acid and 1% ammonium nitrate as additional carbon and nitrogen sources, after 96 h of fermentation. The crude tannate from this isolate showed ph and temperature optima of 5.0 and 50 degree C, respectively. Also, the enzyme was stable in a broad ph range of 3-8 for 24 h and was also heat stable as it retained 65% activity at 70 degree C after 1 hour