Identification of aspergillus species using morphological characteristic and the effect of temperature on the protease activity

摘要

Aspergillus sp. is a fungus that can produce protease enzyme. Aproteolytic enzyme of Aspergillussp is enzymes group that attack the peptide bonds of proteins. In this study, we emphasize on morphological methods including macroscopic and microscopic characteristics for identification of Aspergillus sp. Aspergillus sp was isolated from waste of milk industry. Protease was produced by Aspergillus sp. and the temperature effect was evaluated on its activity, at 37, 40, 45, and 50°C with casein as a substrate. The results obtained show that isolates selected have the green color colony (Fig.1. A,B,C),grown evenly on PDA medium were incubated at 37°C for 4 days, round-shaped vesicles(Fig.1.1), conidiophores somewhat yellowish green nodes, and conidiaspore round and light green. The data of protein contents is shown on Table 1. The average protein contents of the crude enzyme protease extract were 0.95 mg/ml of isolates a, 0.98 mg/ml of isolates B, and 1.03 mg/ml of isolates. Isolate C was selected to produce enzyme and analyze enzyme activities. The enzyme activities of isolate C were 85.85 U/ml at 37°C, 101.87 U/ml at 40°C, 179.00 U/ml at 45°C, and 136.81 U/ml at 50°C. The optimum activity was 179.00 IU/ml and it was reached at 45°C.