Abstract
By use with high concentration of glucoamylase (0.5 RAG/ml), saccharification time could be reduced by one-tenth compared with that of the production field using enzyme unit of 0.1 RAG/m/. Glucose purity of reaction mixture was accomplished over 98%. Furthermore, coloring of the products was scarcely observed. Used enzyme could be recovered by a semi-batch membrane reactor with polysulfone hollow fiber whose molecular cut off was 5000.
Glucoamylase was denaturated in saccharification reaction to the extent of ca. 30% of initial enzyme dosage. This denaturation was prevented by the addition of hydrophilic polymers, chytosan and polyvinylalcohol. In the case of chytosan, when the final concentration was 600 ppm, the rate of denaturation was 15%. These results showed feasibility of the semi-batch membrane reactor in saccharification process.
In the recovery of the enzyme by membrane, volume flux (l/m2·h) was reduced caused by gel formation on the membrane surface. However, the flux could be recovered by increasing the flow rate. Decrease of the flux with time due to fouling of membrane was suppressed by protection of the hydrophobic group by treatment with chytosan and polyvinylalcohol.
