Production of alkaline protease by a genetically engineered Aspergillus oryzae U1521

The production of alkaline protease of Aspergillus oryzae U1521 was examine d in liquid culture. In a culture of defatted soybean only, it gave satisfa ctory enzyme yields at 584,000 U/g defatted soybean. When various carbohydr ates were supplemented, enzyme production was significantly increased. An i ncrease in production by lactose was the most marked. Enrichment with casit one or casein increased productivity, but not cornsteep solid. Media formul ation (g/L) of defatted soybean 10, lactose 5, casitone 1, and KH2PO4 5 enh anced alkaline protease production by A. oryzae U1521 to a maximum of 1,410 ,000 U/g defatted soybean. Scaling-up experiments indicated the flask-scale results could be reproduced at 40 g of substrate in 5-L fermenter. The enz yme activity was maximum between pH 8-9 and at a temperature of 45 degrees C.