Abstract
Glucoamylases produced by Aspergillus niger grown on wheat bran in solid cultures were purified. Four different forms, GA I, GA I', GA II and GA III, were found having apparent molecular weights of 112 000, 104 000, 74 000 and 61 000 Da respectively. The enzymes are glycoproteins with a carbohydrate content of 16%, and optimal activity at 60d̀C and pH 4.4. Activity was strongly inhibited by Hg2+ while Mn2+ and Fe2+ were stimulatory. The Km values for the degradation of starch and maltose were 3.5 and 7.8 mg ml-1, respectively.
View more >>