Production and purification of a-amylase from Aspergillus niger 33-19 CNMN FD 02A mutant form

From mutant micelial strain Aspergillus niger 33-19 CNMN FD 02A, through alcohol ethylic precipitation of cultural liquid, amylolytic preparation Amilonigrin AS was isolated with 10x degree of purity and a specific activity of 138.3U/mg proteins. α-Amylase from 20mM Tris-HCl extract of Amilonigrin AS was purified to homogeneity by PD-10 column gel filtration and HiTrap TM Q column ion exchange chromatography. A trial for the purification of α-amylase resulted in an enzyme specific activity of 199.68U/mg protein with purification fold 8.9. The analyses of purified α-amylase for molecular weight was carried out by SDSPAGE electrophoresis, with revealed two polypeptide bands estimated to be 66 and 40.5kDa, probably being two α-amylaseizoforms.