Production, purification and characterization of alkaline protease from Aspergillus niger MTCC281 by using agro industrial wastes under solid state Fermentation

A comparative study was carried out on the production of protease using wheat bran, rice bran, green gram and black gram as substrates in solid-state fermentation (SSF) by Aspergillus niger MTCC281. Among the all tested varieties, wheat bran showed the highest activity of 69.1 U/mg of protein, while black gram showed lowest activity of 59 U/mg of protein under solid state fermentation conditions. The alkaline protease from wheat bran substrate was produced was purified 16.28 fold and the apparent molecular weight of the enzyme was found to be 45 kDa by SDS-PAGE. The optimal pH and temperature of the enzyme were 8.0 and 40°C, respectively. The enzyme was more stable at the alkaline pH than at the acidic one and it retained 80% of the activity at 50oC for 60 min. All these data suggest that the selected strain of Aspergillus niger MTCC281 can significantly produce protease enzyme from the wheat bran substrate.