A process for conversion of cassava flour to ethanol was developed. This involved direct inoculation
ofAspergillus awamorispores into a cassava flour paste and incubation for some period during which
hydrolytic enzymes are produced (solid state culture orkojiproduction) and subsequent addition of
water and yeast cells, during which there is simultaneous hydrolysis and ethanol production (submerged
culture). When cassava flour alone was used for the solid state phase, the paste was very sticky, making
mixing and aeration difficult. However, addition of rice bran improved the texture and enzyme production. The optima rice bran concentration, spore inoculumconcentration, and duration of solid state culture
before submerged culture were 20%, 6.16×10
6
spores/100 g, and 2 days, respectively. Under these optimum conditions, a high ethanol concentration of 120 g/L and ethanol yield of 0.309 g-ethanol/g-cassava
flour were obtained. This ethanol yield corresponds to 0.44 g-ethanol/g-cassava starch