2.5. Assay of extracellular α-amylase
The method described by Naguib [40] was used. A reaction mixture containing 1 ml of 0.5% soluble starch in acetate buffer (pH 5.6) and 1 ml of the fungal filtrate was incubated at 30°C for 30 min. The amount of reducing sugar (mainly maltose) released was estimated by determining the optical density (absorption spectrum) at 700 nm wave in the spectrophotometer. Reducing sugars were determined by comparison with a standard curve for maltose.