65
ProCess engineering of solid- state fermentation
1988). Gowthaman et al. (1995) reported a method for the estima-
tion of overall kL a in SSF on the basis of the inlet and outlet oxygen
concentrations, assuming that the decrease in oxygen concentration
within the liquid film was always 10% of the saturation concentra-
tion (Gowthaman et al., 1995). For mycelial growth in SSF, the fun-
gal hyphae exposed directly to the air can probably take up oxygen
directly from the air. It is well reported that the productivity in SSF is
much higher than in SmF. One of the main reasons is the high inter-
facial area per unit volume. But this alone cannot explain completely
the observed effect. ere is no free- flowing water in SSF, and the
water content is just ...