| Abstract: | In most enzymatic reactions, batch or continuous, separation of the enzyme for reuse is difficult if not impossible. A process will be presented in which an Ultrafiltration membrane serves to separate the reaction products from the enzyme and the substrate. In this manner the enzyme may be retained and re-used. Furthermore, under these conditions, the enzyme need only be present in catalytic amounts regardless of the amount of product produced. Under proper operating conditions and proper ultrafiltration membrane selection, a pure solution of α-amylase from Bacillus subtilis may be retained with no loss in enzyme activity over a test period of 30 hr after steadystate has been achieved. In the presence of substrate, the membrane support and ultrafiltration cell serve as the reaction vessel for the hydrolysis of starch. The substrate is continuously pumped into the cell under constant ultrafiltration pressure. The di-, oligo-, and polysaccharides formed from the enzyme reaction then either pass through the membrane as products or are retained. The molecular weight distribution of the products is dependent on the nominal molecular weight cut-off of the membrane, absolute ultrafiltration pressure, enzyme-to-substrate ratio, temperature, and residence time of the substrate in the reactor. In addition to the partial hydrolysis of starch by α-amylase, some preliminary findings on the complete hydrolysis of starch by glucoamylase will also be presented. In these latter studies, the substrate may be completely hydrolyzed to glucose units. |
