AbstractIn order to utilize raw sago starch as fermentation material, mold strain (Aspergillus niger N‐10) which produces raw sago starch hydrolyzing enzyme, was isolated. Maximum raw sago starch consumption rate by the strain was obtained when the initial pH of the medium was 3.5 and the enzyme showed high stability and activity at lower pH values. Direct ethanol production from raw sago starch was investigated using a mixture of the strain and ethanol producing yeast, Saccharomyces cerevisiae IFO 0309. Neither the growth of the strains nor ethanol production was inhibited in the mixed culture of the two strains. Moreover, when fed‐batch mixed culture was conducted under unsterile condition (both the medium and the apparatus were not sterilized), about 30g/1 of ethanol was produced with ethanol yield from raw sago starch Yp/s of 0.40g ethanol/g starch.