Aspergillus oryzae

Aspergillus oryzae
A. oryzae growing on rice to make koji
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Eurotiomycetes
Order: Eurotiales
Family: Aspergillaceae
Genus: Aspergillus
Species:
A. oryzae
Binomial name
Aspergillus oryzae
(Ahlburg) E. Cohn[1]

Aspergillus oryzae is a mold used in East Asia to saccharify rice, sweet potato, and barley in the making of alcoholic beverages such as sake and shōchū, and also to ferment soybeans for making soy sauce and miso. It is one of the different koji molds ニホンコウジカビ (日本麹黴) (Japanese: nihon kōji kabi) used for food fermentation.

However, in the production of fermented foods of soybeans such as soy sauce and miso, Aspergillus sojae is sometimes used instead of A. oryzae.[2][3] A. oryzae is also used for the production of rice vinegars. Barley kōji (麦麹) or rice kōji (米麹) are made by fermenting the grains with A. oryzae hyphae.[4]

Genomic analysis has led some scholars to believe that the Japanese domesticated the Aspergillus flavus that had mutated and ceased to produce toxic aflatoxins, giving rise to A. oryzae.[5][6][7] While the two fungi share the same cluster of genes that encode for aflatoxin synthesis, this gene cluster is non-functional in A. oryzae.[8] Eiji Ichishima of Tohoku University called the kōji fungus a "national fungus" (kokkin) in the journal of the Brewing Society of Japan, because of its importance not only for making the kōji for sake brewing, but also for making the kōji for miso, soy sauce, and a range of other traditional Japanese foods. His proposal was approved at the society's annual meeting in 2006.[9]

The Japanese word kōji (麹) is used in several meanings, and in some cases it specifically refers to A. oryzae and A. sojae,[2][10] while in other cases it refers to all molds used in fermented foods, including Monascus purpureus and other molds, so care should be taken to avoid confusion.[11]

  1. ^ Index Fungorum
  2. ^ a b Kenichiro Matsushima. しょうゆづくりの歩みと麹菌の関わり (PDF) (in Japanese). The Society for Biotechnology, Japan. p. 75. Archived from the original (PDF) on 26 July 2020.
  3. ^ 麹菌ゲノム解読 Kikkoman Corporation
  4. ^ Parmjit S. Panesar, Biotechnology in Agriculture and Food Processing: Opportunities and Challenges CRC Press (2014)
  5. ^ Katsuhiko Kitamoto. 麹菌物語 (PDF) (in Japanese). The Society for Biotechnology, Japan. p. 424. Archived from the original (PDF) on 31 October 2022.
  6. ^ Katsuhiko Kitamoto. 家畜化された微生物、麹菌 その分子細胞生物学的解析から見えてきたこと (PDF) (in Japanese). The Society of Yeast Scientists. p. 2. Archived from the original (PDF) on 13 November 2022.
  7. ^ Kiyoko Hayashi (19 July 2021). 日本の発酵技術と歴史 (in Japanese). Discover Japan Inc. Archived from the original on 10 November 2022.
  8. ^ Kiyota, Takuro; Hamada, Ryoko; Sakamoto, Kazutoshi; Iwashita, Kazuhiro; Yamada, Osamu; Mikami, Shigeaki (May 2011). "Aflatoxin non-productivity of Aspergillus oryzae caused by loss of function in the aflJ gene product". Journal of Bioscience and Bioengineering. 111 (5): 512–517. doi:10.1016/j.jbiosc.2010.12.022. ISSN 1389-1723. PMID 21342785.
  9. ^ Fujita, Chieko, Tokyo Foundation Koji, an Aspergillus Archived 2009-05-22 at the Wayback Machine
  10. ^ Kenichiro Matsushima. 醤油づくりと麹菌の利用ー今までとこれからー (in Japanese). p. 643. Archived from the original on 21 June 2022.
  11. ^ 麹のこと Marukome co., ltd.