Aspergillus oryzae, known in English as koji (Japanese: 麹, Hepburn:
kōji), is a filamentous fungus (a mold) used in Chinese and other
East Asian cuisines to ferment soybeans for making soy sauce and
fermented bean paste, and also to saccharify rice, other grains, and
potatoes in the making of alcoholic beverages such as huangjiu, sake,
makgeolli, and shōchū. The domestication of A. oryzae occurred at
least 2000 years ago. A. oryzae is also used for the production of
Dr. 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 koji for sake
brewing, but also for making the koji for miso, soy sauce, and a range
of other traditional Japanese foods. His proposal was approved at the
society's annual meeting in 2006.
"Red kōji-kin" is a separate species, Monascus purpureus.
1 History of koji
2 Properties desirable in sake brewing and testing
3 Varieties used for shōchū making
5 Use in biotechnology
7 See also
9 External links
History of koji
300 BCE –
Aspergillus is first mentioned in the Zhouli (Rites of the
Zhou dynasty) in China. Its development is a milestone in Chinese food
technology, for it provides the conceptual framework for three major
fermented soy foods: soy sauce, jiang / miso, and douchi, not to
mention grain-based wines (including Japanese sake) and li (the
Chinese forerunner of Japanese amazake).
Properties desirable in sake brewing and testing
The following properties of A. oryzae strains are important in rice
saccharification for sake brewing:
Growth: rapid mycelial growth on and into the rice kernels
Enzymes: strong secretion of amylases (α-amylase and glucoamylase);
some carboxypeptidase; low tyrosinase
Aesthetics: pleasant fragrance; accumulation of flavoring compounds
Color: low production of deferriferrichrome (a siderophore), flavins,
and other colored substances
Varieties used for shōchū making
Three varieties of kōji mold are used for making shōchū, each with
White was discovered at the beginning of the
Taishō period when
natural mutation and separation of some black kōji to white was
observed. This effect was researched and white kōji was successfully
grown independently. White kōji is easy to cultivate and its enzymes
promote rapid saccharization; as a result, it is used to produce most
shōchū today. It gives rise to a drink with a refreshing, gentle,
Black is mainly used in Okinawa to produce awamori. It produces plenty
of citric acid which helps to prevent the souring of the moromi. Of
all three kōji, it most effectively extracts the taste and character
of the base ingredients, giving its shōchū a rich aroma with a
slightly sweet, mellow taste. Its spores disperse easily, covering
production facilities and workers' clothes in a layer of black. Such
issues led to it falling out of favour, but due to the development of
new kuro-kōji (NK-kōji) in the mid-1980s, interest in black kōji
resurged amongst honkaku shōchū makers because of the depth and
quality of the taste it produced. Several popular brands now
explicitly state they use black kōji on their labels.
Yellow is used to produce sake, and at one time all honkaku shōchū.
However, yellow kōji is extremely sensitive to temperature; its
moromi can easily sour during fermentation. This makes it difficult to
use in warmer regions such as Kyūshū, and gradually black and white
kōji became more common. Its strength is that it gives rise to a
rich, fruity, refreshing taste, so despite the difficulties and great
skill required, it is still used by some manufacturers. It is popular
amongst young people and women who previously had no interest in
typically strong potato shōchū, playing a role in its recent
Initially kept secret, the A. oryzae genome was released by a
consortium of Japanese biotechnology companies in late 2005.
The eight chromosomes together comprise 37 million base pairs and 12
thousand predicted genes. The genome of A. oryzae is thus one-third
larger than that of two related
Aspergillus species, the genetics
model organism A. nidulans and the potentially dangerous A.
fumigatus. Many of the extra genes present in A. oryzae are
predicted to be involved in secondary metabolism. The sequenced strain
isolated in 1950 is called RIB40 or ATCC 42149; its morphology,
growth, and enzyme production are typical of strains used for sake
Use in biotechnology
Resveratrol can be produced from its glucoside piceid through the
process of fermentation by A. oryzae.
Conidiophores with conidia of the microscopic fungi
under light microscope
Aspergillus colonies grown at 37 °C for three days on rich
media. The bottom two are
Aspergillus oryzae strains.
^ Index Fungorum
^ a b Rokas, A. (2009). "The effect of domestication on the fungal
proteome". Trends in genetics : TIG. 25 (2): 60–63.
doi:10.1016/j.tig.2008.11.003. PMID 19081651.
^ Fujita, Chieko, Tokyo Foundation Koji, an Aspergillus
^ Shurtleff, W.; Aoyagi, A. History of Koji - Grains and/or Soybeans
Enrobed with a
Mold Culture (300 BCE to 2012). Lafayette, California:
Soyinfo Center. 660 pp. (1,560 references; 142 photos and
illustrations, Free online)
^ Kitamoto, Katsuhiko (2002). "Molecular Biology of the Koji Molds".
Advances in Applied Microbiology. Advances in Applied Microbiology.
51: 129–153. doi:10.1016/S0065-2164(02)51004-2.
ISBN 9780120026531. PMID 12236056. Retrieved
^ "In-depth". Retrieved 2007-01-24. (Japanese)
^ "What is Shochu?". Retrieved 2007-01-24.
^ "Other terminology relating to Shochu and Awamori". Retrieved
^ "Shochu Circle". Retrieved 2007-12-11.
^ Goffeau, André (December 2005). "Multiple moulds". Nature. 438
(7071): 1092–1093. doi:10.1038/4381092b. PMID 16371993.
^ Machida, Masayuki; et al. (December 2005). "
Genome sequencing and
Aspergillus oryzae". Nature. 438 (7071): 1157–1161.
doi:10.1038/nature04300. PMID 16372010.
^ Galagan JE, et al. (December 2005). "Sequencing of Aspergillus
nidulans and comparative analysis with A. fumigatus and A. oryzae".
Nature. 438 (7071): 1105–1115. doi:10.1038/nature04341.
^ Wang, H.; Liu, L.; Guo, Y. -X.; Dong, Y. -S.; Zhang, D. -J.; Xiu, Z.
-L. (2007). "Biotransformation of piceid in Polygonum cuspidatum to
Aspergillus oryzae". Applied Microbiology and
Biotechnology. 75 (4): 763–768. doi:10.1007/s00253-007-0874-3.
Sake World's description of koji
Aspergillus oryzae genome from the Database of Genomes Analysed at