Table 1.

Advantages and disadvantages of SSF over SmF (Raimbault 1998; Hölker et al. 2004; Couto and Sanroma 2006)

Advantages	Disadvantages
Low-cost media	Difficulties on scale-up
Higher productivity	Mixing of nutrients not uniform
Better oxygen circulation	Problems with heat build-up
Catabolite repression is negligible	Higher impurity product
Absence of foam formation so no requirement of antifoaming agent	Recovery cost is high
It resembles the natural habitat for several microorganisms	Difficult control of process parameters
Less effort in downstream processing
Simple technology
Less energy demand for heating
Fermentation of water in-soluble material
Requires smaller reactor volume
Less chance of contamination