Two samples of low-grade wheat flour, namely low-grade 1 (LG1) and low-grade 2 (LG2), with different carbohydrate and fibrous content, were used as substrates. The samples were liquefied using various concentrations of alpha- or beta-amylase, in order to optimize the production of fermentable sugars; the enzyme alpha-amylase revealed higher performance. After liquefaction, the simultaneous saccharification and fermentation was conducted in a jar fermentor. Amyloglucosidase was used for saccharification, and dry baker's yeast, S. cerevisiae, for fermentation simultaneously. Glucose was consumed promptly in both cases, LG1 and LG2; ethanol production was considerably higher in LG1 (38.6 g/L), compared to LG2 (24.9 g/L). The maximum ATP production was observed early in the SSF process. LG1 revealed higher potential as substrate for ethanol production.
Low grade; wheat flour; yeast; fermentation; ethanol
