Production, Purification and Characterization of Protease by Aspergillus flavus under Solid State Fermentation

Abstract

Protease production under solid state fermentation (SSF) was investigated using isolated Aspergillus flavus. Different agroindustrial waste products were evaluated to check the possibility of potential utilization of substrates in SSF for protease production by Aspergillus flavus using wheat bran as a substrate. The results showed that the optimum conditions for maximum protease production were found to be 7 th day of incubation at pH 5.0, temperature 30 o C; inoculum size 3%; substrate concentration 3% and 3% KNO3 as nitrogen source. The purified enzyme produced 5.8 fold with recovery of 3.2% by DEAE-column chromatography and the molecular weight was estimated to be 46kDa by SDS-PAGE. It has a Vmax value of 60.0 U/mg and Km value of 0.6 mg/ml at pH of 7. The enzyme activity was found to be stable at 50 0 C and it was stimulated by metal ions like Cu 2+ and Zn 2+ and inhibited by Ca 2+ and Mg 2+ .