Koji Aspergillus Oryzae Enzyme Science
Japan — documented koji use since 8th century in Nihon Shoki chronicles
Koji (Aspergillus oryzae) is the foundational microorganism of Japanese fermentation, responsible for sake, miso, soy sauce, mirin, and shio koji. Koji produces amylases (breaking starch to sugar) and proteases (breaking protein to amino acids including glutamate — creating profound umami). Koji cultivation requires precise temperature management: rice inoculated with spores held at 30-40°C in high humidity over 40-48 hours. The resulting koji-mai (koji rice) forms the saccharification base for sake and provides enzymatic power for miso and soy sauce fermentation.