Abstract

The fungal isolates identified as Aspergillus fumigatus and Aspergillus flavus isolated from a local rice husk dumpsite were screened for protease enzyme production. High yields of protease enzyme were obtained by both fungi after 144 h with concentrations of 0.96 µg/ml/min for A. flavus and 0.84 µg/ml/min for A. fumigatus. Optimum temperature for the activity of protease produced by A. flavus and A. fumigatus was at 30°C with protease activities of 0.46 and 0.43 µg/ml/min, respectively. Optimum pH for the activity of protease produced by A. flavus and A. fumigatus were pH 8 and 5, respectively. The result showed that both isolates were good producers of extracellular protease enzymes which can be useful in industries.

Key words: Protease, rice husk, optimization, Aspergillus fumigatus, Aspergillus flavus