Conclusions
Solid state fermentation of chopped sweet sorghum particles
to produce ethanol was studied statically using thermotolerant yeast. The influence of various process parameters, such
as yeast cell concentration, particle size, moisture content, on
the ethanol yield was investigated.
Optimal values of these parameters were found to be 4× 106
cells/g raw sorghum stalks, 0.5–1.5 mm and 75% moisture
level, respectively. With the reducing agent of 30 mg H2SO3/
100 g fresh sorghum stalks, the maximum ethanol yield was
7.9 g ethanol per 100 g fresh stalks or 0.46 g ethanol/g total
sugar after 40 ± 2 h, which is 91% of the theoretic yield.