Soybean molasses (SM) is a by-product of soybean meal concentrate. It is rich in sucrose, raffinose and
stachyose. Stachyose and raffinose are not directly fermentable to ethanol but, when hydrolyzed, can
be metabolized by Saccharomyces cerevisiae. In this work, we studied (1) the production of ethanol from
natural SM by fermentation with S. cerevisiae, (2) the enzymatic hydrolysis of SM by -galactosidase and
the subsequent fermentation with S. cerevisiae (HF), and (3) ethanol production via the simultaneous
hydrolysis and fermentation (SHF) of SM. The results showed that, although the fermentation of natural
soybean molasses provided a fermentation yield of 72.9% under optimized conditions, hydrolyzed soybean
molasses provided a fermentation yield 7.6% higher using the HF process and 8.2% higher using SHF.
Both fermentation processes resulted in lower concentrations of residual sugar.