A cloth strip bioreactor with immobilized glucoamylase

Glucoamylase was immobilized on polyethylenimine (PEI)-coated cotton cloth by adsorption followed by cross-linking with 0.2% glutaraldehyde in the presence of starch. Optimal adsorption of the enzyme was seen when cloth treated with 2% PEI was contacted with the enzyme for 50 min. pH and temperature optima profiles were not changed appreciably on immobilization. However, the bound enzyme exhibited a higher thermal stability. The enzyme-bound cloth strips were used in a specially designed bioreactor for the continuous hydrolysis of starch. The reactor could be operated for over 21 days retaining about 70% of the original activity. An operational temperature of 45 degrees C was found to be optimal.