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Microbiology List: question re culturing koji

Rupal Deva rupal at cipmail.ukbf.fu-berlin.de
Fri Jul 20 21:28:42 EST 2001

Hello there!

Koji  is made by steaming white short grained rice, barley or soybeans,
cooled to 35 deg. C, innoculated with mold spores of  Aspergillus oryzae
This should then incubated for 3 to 4 days at app. 42 deg. C at 90 - 95%
humidity, stirred in intervals during incubation to reduct or eliminate
excess heat from building up. This also helps the mold grow prolifically
and evenly through the entire rice. Koji is ready for harvest prior
sporulation or maturation of the mold (when matured, the spores of this
mold are pale green). This will ensure peak enzyme activity and good

The temperature and humidity condition is important in taking into
account. there could be growth or sporulation in differnt condition.. but
not to the desired level.

Hope it helps you

On 18 Jul 2001, A Grimes wrote:

> I have an unusual question.  I am trying to grow koji, which is the fungus
> Aspergillus oryzae on rice.  This item is used in the manufacture of various
> Japanese foods like miso, sake and soy sauce.  The fungus makes an enzyme
> that converts starch to fermentable sugar.
> I have in my possession some of the spores of this fungus, and have been
> able to culture them on rice at a temperature of about 35 C for 2 or 3 days.
> I would like the fungus to go to spore (which the Japanese call tane koji)
> so that I can inoculate more rice.  I know the process as done in Japan
> involves rice, wood ash and the spores.  Should I just let the fungus grow
> longer on the rice?  Will conditions of temperature or humidity cause the
> mold to form spores?  Hopefully, someone reading this newsgroup will be
> familiar with the process and can help, but I'd appreciate any help anyone
> can give me.  Thanks in advance.
> Adam Grimes


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