The intermittently mixing events should be used:
To prevent undue aggregation of substrate particles, unduly high
pressure drops, and the appearance of cracks and channels in the bed;
To control water activities in the bed by using replenish water in the
bed (in order to prevent low water activities in the bed from being one
of the factors that limit growth).
Furthermore, to control the temperature in such bioreactors,
manipulation of the temperature, humidity, and flow rate of the inlet
air can help.