Figure 5.

Effect of temperature on the activity (a) and stability (b) of the extracellular proteinases of A. niger I1. The temperature profile was determined by assaying proteolytic activity at temperatures between 30°C and 70°C. The activity of the enzyme at 50°C and pH 4.0 using hemoglobin as a substrate was taken as 100%. The temperature stability was determined by incubating the crude enzyme in different temperature for 1 h, and the residual activity was measured at pH 4.0 and 50°C with hemoglobin as a substrate. The nonheated enzyme was considered as 100% control.