The production of ethanol from sorghum grains was investigated in the present work. Initially, starch enzymatic hydrolysis was investigated using commercial α-amylase and glucoamylase, considering particle size, solid:liquid ratio and enzyme load as variables. The hydrolysate, in the best conditions (73 U of α-amylase/g grain and 1150 U glucoamylase/g grain), contained glucose at a concentration of approximately 250 g/L, which was fermented to produce ethanol in a bioreactor in batch mode. Using an industrial strain of Saccharomyces cerevisiae, the maximum ethanol concentration produced was roughly 106 g.L-1 in 24 h of fermentation, resulting in a volumetric productivity of 4.4 g.L-1.h-1 and a product yield based on the substrate consumed (0.499 g.g-1) close to the theoretical.
Sorghum Grains; Enzymatic Hydrolysis; Ethanol; Fermentation; Saccharomyces cerevisiae
