Abstract

Two hundred and seventy Bacillus species were isolated from soil samples in Khartoum State and tested for α- amylase production. 20 potential isolates of α- amylase producer were obtained during primary screening. Secondary screening of these isolates yielded a high thermostable alkaline α- amylase producing isolate. Of all the species tested, Bacillus licheniformis gave maximum α-amylase activity of 0.7947 U/mg/ml at pH of 8 in iodine method, and (0.024 U/mg/ml) in 3.5.dinitrosalicylic acid (DNS) method. Characterization of the extra-cellular crude α- amylase was further evaluated for its biochemical properties as an enzyme for industrial use. The production of α- amylase following growth of the microorganism was found to be at optimum temperature and pH of 70°C and 9.0, respectively.

Key words: Thermostable α- amylase, alkaline α- amylase, Bacillus licheniformis.