Production, purification, and characterization of Thermoanaerobacterium thermosaccharolyticum glucoamylase

Glucoamylase from Thermoanaerobacterium thermosaccharolyticum ATCC 7956 (DSM 571) was produced in extracellular form. It was purified to homogeneity by two separate methods, one with two chromatographic steps and the other with three. This glucoamylase is closely related to glucoamylases from Clostridium sp. G0005 and T. thermosaccharolyticum DSM 572. Activities and K_M values with maltose substrate are less than one-tenth and about fourfold, respectively, those of Aspergillus niger glucoamylase. T. thermosaccharolyticum glucoamylase is about twenty times as thermostable as A. niger glucoamylase and its optimal pH is somewhat higher at 4.9; however, it is produced in much lower activities. Sorbitol strongly stabilizes A. niger glucoamylase.