An Effective Production Method of Glucoamylase in a Novel Solid-State Culture System

Soft and porous material of urethane foams as carriers (UFC), which were impregnated with a liquid medium, were studied an effective cultivation system of Aspergillus oryzae B-3. Gelatin modified urethane foam was used by cutting into 5mm in side length cubes. We have impregnated 1g of the UFC with 19ml of this liquid medium. The total volume of this reactor was 850ml. Eight g of the UFC, whose bulk volume was about 480 ml, was taken into the new bioreactor. After appropriate time of initial batch cultivation, the liquid containing enzyme was squeezed from the UFC by pressing the squeezing plate. Then, the fresh medium was introduced into the reactor. The maximum production activity of glucoamylase was attainable under the condition where the initial concentration of sugar was around 35,000mg/l and the moisture content was kept about 80%. We have succeeded to produce glucoamylase about 5 times higher in the total activity and 2.5 times higher in the yield for sugar than they are producible by the conventional solid-state fermentation method.