SACCHARIFICATION IN MEMBRANE REACTOR FOR IMMOBILIZING GLUCOAMYLASE

Glucoamylase was immobilized on a capillary membrane of UF by the glut araldehyde cross-linkage method. The membrane has an asymmetric struct ure and contains a great number of amino groups in porous areas. Lique fied starch of DE 13 was used as substrate and forced by applying pres sure to permeate through the membrane. The obtained permeate once agai n permeated through the immobilized membrane. However, polymers in the liquefied starch were rejected by the membrane, and the glucose conte nt in permeate was not more than 94%. Permeability of the polymers thr ough the membrane was improved by making the skin layer of membrane po rous and using liquefied starch of DE 20. Glucose content in permeate increased by using glucoamylase co-immobilized with pullulanase. The g lucose formation rate increased and the glucose content reached 97%. T he hydrolysis ratio of polymers in the substrate was higher when using glucoamylase with pullulanase than that when using only glucoamylase. Even if pullulanase was added to substrate of nearly 90% glucose cont ent, glucose formation proceeded smoothly. It was found that continuou s saccharification of liquified starch was possible by use of glucoamy lase immobilized on a porous membrane in the first stage of reaction a nd that co-immobilized with pullulanase in the final stage.