REPEATED BATCH-PRODUCTION OF ALKALINE PROTEASE BY SOLID-STATE FERMENTATION USING URETHANE FOAM AS CARRIERS

By immobilizing fungi on a urethane foam carrier (UFC), a novel solid- stale fermentation system was developed in order to produce repeatedly industrial useful enzymes. In this study, alkaline protease was produ ced by growing Aspergillus oryzae 460 (ATCC 20386) in a flask scale. R epeated batch production of alkaline protease was carried out by excha nging a part of the culture broth with fresh medium every 12 hr. The e ffects of feeding medium composition, and feeding volume were examined . Alkaline protease production stopped in the early phase at high valu es of soluble starch feeding rate and culture broth dilution rate. The enzyme production continued longer when 10 to 30 g/l polypepton was a dded to the feeding medium. Using soluble starch solution as feeding m edium, a maximum activity of 520,000 U/l-bulk volume alkaline protease was obtained at culture time of 168 hr where the culture conditions o f soluble starch concentration and feeding volume were 100 g/l and 0.0 25 l/l-bulk volume/dose, respectively. Production of the enzyme contin ued for 300 hr and total aklaline protease activity reached 870,000 U/ l-bulk volume by adding 30 g/l polypepton to the fresh medium.