
75
ProCess engineering of solid- state fermentation
3.3.1 Balance of Oxygen
Smits et al. proposed the model describing the oxygen balance rela-
tionship of the substrate bed in the tray reactor (Smits et al., 1999):
aC
D
aC
r
b
O
O
O
O
2
2
2
2
2
, (3.7)
where means time,
b
means oxygen concentration of unit volume
bed (vertical coordinate),
means diffusion rate, and r
O
2
means
ingesting the oxygen rate of the micro organ ism.
Rajagopalan and Modak (1995) considered the effect of biomem-
brane covering the bed face in the models. Oxygen transmission
through the bed airgap was described in the equation:
=
D
Ka CHC
b
zx
f
O
O
O
O
O
2
2
2
2
2
2
, (3.8)
where ...