Productivity of Citric Acid of Aspergillus oryzae, Producing Excessive Acids, Isolated from Ina-Koji

Aspergillus oryzae N-1 and N-4 were isolated from ina-koji. Those isolates produced citric acid 4 times much as Aspergillus oryzae RIB-176, using sake making, in rice koji. Using the rice koji of 40% moisture, A. oryzae N-1 produced a great deal of citric acid in polished rice of 73.8% at 32°C and A. oryzae N-4 in polished rice of 53.6% at 37°C.