Abstract
Two strains of Aspergillus niger were propagated on Czapek broth medium using submerged culture in a shaker incubator at 30 °C and 125 rpm to produce glucose oxidase. The strain ATCC 166808 was selected because it gave higer enzymatic activity than the strain IMI 84305. The presence of glucose and sucrose in the medium at concentration of 20 gm/l for each enhanced maximum enzyme production after 3 days of incubation. The enzyme was found to be intracellular and the sonication time required to rupture the cellular walls was 15 minutes at 10 KHz. The enzyme was precipitated from the cell-free extract by the addition of 2 volumes of cold acetone and was partially purified by gel filtration chromatography using Sephadex G-150 followed by ion-exchange chromatography in a DEAE-cellulose column. A specific activity of 8528.6 units/mg protein and a purification of 53.2 folds with a yield of 47.6% was achieved.
