Intermittently agitated designs have been used in the koji industry.
Sato and Sudo (1999) report a bioreactor with a capacity of 15 tons
of rice koji on a 12 m diameter disk (Fig. 10.2). The maximum
height of the substrate bed is of the order of 20 cm. The solid bed
has a packing density of 400 kg/m3 and a volume of 37.5 m3.
The inoculated substrate is placed in the upper chamber, where it
remains for one day. After this period the screw mixer is used to
transfer the substrate to the bottom chamber.