Koji Ceramide Project

Koji is the Japanese traditional fermented food which has a history of more than 1000 years (probably with the primary dynasty of Japan).
This website introduces academic information about Japanese koji.


What is koji?
Koji is steamed rice fermented with nonpathogenic fungus, Aspergillus oryzae or A. luchuensis.
By utilizing the property that these fungi secretes abundant starch-degrading enzymes, it has been used as the starch-degrading (saccharifying) reagent in the production process of fermented foods in Japan.

Are koji and Aspergillus safe?
Since koji has been ingested by Japanese people for a long time, USA FDA admits koji as GRAS (Generally Regarded as Safe).
Recent genomic analysis shows that A. oryzae and A. luchuensis does not have functional genes to produce mycotoxins such as aflatoxin (Nature. 2005; 438(7071):1157-61.).

History of Koji
Food fermentation using fungus is described in Japan in 713 AD, and food fermentation technologies using koji are described in detail in 970 AD. Since a battle of the koji industry sponsored by the Kyoto Kitano Academic Shrine, one of the most influential shrines in Japan, and the fermentation industry occurred in 1246 AD, microbiological methodology has been established. Therefore, it is considered that before 1246 AD, A. oryzae had been isolated and utilized in the industry in Japan.

Japanese traditional foods which use koji
Koji drink Amazake (Rice drink saccharified with koji)
Sake (alcoholic drink) koji is used as the saccharifier of starch in rice
Osu (Rice vinegar) koji is used as the saccharifier of starch in rice
Kurosu (Black rice vinegar) koji is used as the saccharifier of starch in crops
Shochu (distilled alcoholic drink) koji is used as the saccharifier of starch in crops

Health benefits of koji
Koji contains abundant beta-glucan, which stimulates immunity through macrophages.
Koji contains glycosylceramide, which improves intestinal microbial flora and lowers liver cholesterol.
Koji glycosylceramide activates barrier function genes of human skin cells.
Degradation product of koji glycosylceramide activates PPAR.

The structure of glycosylceramide



麹セラミドプロジェクト

麹セラミドの機能性を解明しようという佐賀大学のプロジェクトです(メンバー:佐賀大学 北垣浩志教授、光武進准教授、永尾晃治教授)。
麹は日本の発酵食品のほとんどに使われ、日本の発酵食品の基盤ともいえるものです。
これまでに

日本の発酵食品(甘酒、塩こうじ、味噌、濁り酒など)に麹セラミドが多く含まれること
麹セラミドにBlautia coccoidesなどの善玉菌を増やす腸内細菌叢の改善効果があること
麹セラミドに肝臓コレステロール低下効果があること
麹セラミドにヒトの肌の角質細胞のバリア機能の活性化機能があること
麹セラミドの分解物にメタボリックシンドローム改善効果のある転写因子PPARの活性化能があること
などを見出しています(以下の発表論文参照)。

現在、続々と新たな発見を行っていますので、論文になるまでお待ちください。

Koji glycosylceramide commonly contained in Japanese traditional fermented foods alters cholesterol metabolism in obese mice.

Hamajima H, Tanaka M, Miyagawa M, Sakamoto M, Nakamura T, Yanagita T, Nishimukai M, Mitsutake S, Nakayama J, Nagao K, Kitagaki H.

Biosci Biotechnol Biochem. 2018 Dec 30:1-9. doi: 10.1080/09168451.2018.1562877. [Epub ahead of print]

Japanese traditional dietary fungus koji Aspergillus oryzae functions as a prebiotic for Blautia coccoides through glycosylceramide: Japanese dietary fungus koji is a new prebiotic.

Hamajima H, Matsunaga H, Fujikawa A, Sato T, Mitsutake S, Yanagita T, Nagao K, Nakayama J, Kitagaki H.

Springerplus. 2016 Aug 11;5(1):1321. doi: 10.1186/s40064-016-2950-6. eCollection 2016. Erratum in: Springerplus. 2016 Oct 25;5(1):1869.


Glycosylceramides Purified from the Japanese Traditional Non-Pathogenic Fungus Aspergillus and Koji Increase the Expression of Genes Involved in Tight Junctions and Ceramide Delivery in Normal Human Epidermal Keratinocytes
Miyuki Miyagawa, Ayami Fujikawa, Mayu Nagadome, Kanae Kohama, Takatoshi Ogami, Seiichi Kitamura and Hiroshi Kitagaki
Fermentation 2019, 5(2), 43; https://doi.org/10.3390/fermentation5020043
https://www.mdpi.com/2311-5637/5/2/43

Structural determination of glucosylceramides in the distillation remnants of shochu, the Japanese traditional liquor, and its production by Aspergillus kawachii.

Hirata M, Tsuge K, Jayakody LN, Urano Y, Sawada K, Inaba S, Nagao K, Kitagaki H.

J Agric Food Chem. 2012 Nov 21;60(46):11473-82. doi: 10.1021/jf303117e. Epub 2012 Nov 12.


 2014;63(1):15-23.

Quantitation and structural determination of glucosylceramides contained in sake lees.

Takahashi K1, Izumi K, Nakahata E, Hirata M, Sawada K, Tsuge K, Nagao K, Kitagaki H.


The fungal 9‐methyl‐sphingadiene is a novel ligand for both PPARγ and GPR120
Shota Esaki Tomotaka Nagasawa Haruka Tanaka Aoi Tominaga Daisuke Mikami Seigo Usuki Hiroshi Hamajima Hisatoshi Hanamatsu Shota Sakai Yoichiro Hama Yasuyuki Igarashi Hiroshi Kitagaki Susumu Mitsutake
Journal of Food Biochemistry, Volume42, Issue5 2018 e12624

Development of a quantitative method for the contents of glycosylceramide contained in Japanese fermented foods brewed with koji and its application.
J. Brew. Soc. Jpn, 112, 9, 655-662(2017)

Structural determination by electrospray ionization tandem mass spectrometry (ESI-MS/MS) of glucosylceramides in the distillate of potato shochu, the traditional Japanese liquor produced from sweet potato.
J. Brew. Soc. Jpn, 109, 7, 535-542 (2014)