Purification and characterization of extracellular tannase from Aspergillus fumigatus MA using Syzigium cumini leaves under solid state fermentation

This study reports the tannase purification produced by a tannery effluent-originated fungal isolate i.e., Aspergillus fumigatus MA under solid state fermentation (SSF) condition. Purification of tannase from culture filtrate was attained using ammonium sulfate precipitation with subsequent diethylaminoethyl (DEAE)-cellulose mediated ion exchange chromatographic technique. Fractional precipitation of the culture filtrate with 60-80% ammonium sulfate yielded 80.9% recovery of tannase with 6.16-fold purification. The enzyme fractions were collected and eluted as a single peak using 0.5 M NaCl-gradient concentration. DEAE-cellulose column chromatography results in overall 23-fold purification with 27.6% recovery of the enzyme. SDS-PAGE analysis of purified tannase confirmed the presence of a single band of protein with a molecular mass equivalent to 66.2 kDa. The highest activity of tannase was observed at optimum pH ranged between 5.0-6.0 whereas, the tannase stability (>80%) was observed at 4.0 to 7.0 pH ranges. The purified tannase activity was found to be optimally active at 30 °C whereas stability (>90%) was accomplished between 30-50 °C temperature. The K_m and V_max were found to be 1.61 × 10^-3 M and 1.04 mM respectively. These properties suggest the potential of the enzyme to be utilized in various food, feed, and pharmaceutical sectors.