Alarger culture bottle (the cross-section area is 2.5 times greater
than that used in the above-described experiment) was used to
check the influences of scale-up on the cordycepin production.
According to the paper reported by Sakurai et al., the productivity
of citric acid by the surface culture depended on the medium
depth [42]. Therefore, in this scale-up test, the medium depth for
the large scale was fixed at the same level as that of the small scale.
The experiments were carried out in two conditions. One was the
substrate level 1.0 with the water-supplement and the other was
the substrate level 0.75 without the water-supplement (Fig. 8).