The use of adsorbed cellulase in the continuous conversion of cellulose to glucose

Cellulose strongly adsorbs cellulase at pH 4.0‐5.0, 25‐50°C, conditions which are optimum for the enzyme action. The adsorbed enzyme is sufficient to digest the cellulose with no replenishment of enzyme even though the liquid phase containing the sugar is continuously removed. As cellulose is digested, the released enzyme is readsorbed on excess or newly added cellulose with retention of activity. Sugars can be separated from the enzyme‐cellulose complex by simple filtration or centrifugation or by retaining the enzyme‐cellulose complex in a column from which the sugar solution is eluted. Adsorbed cellulase has been used to produce syrups containing 5‐14% glucose continuously from stirred reactors containing 10‐20% cellulose, or from cellulose columns.