Abstract

• Bioethanol was prepared from powder of sorghum (Sorghum biocolor L. Moench) grain by enzymatic hydrolysis. α–Amylase from germinated wheat grains was used for liquefaction of starch and α–glucosidase from ungerminated flint corn was used in saccharification step. After liquefaction and saccharrification, the solution was tested for glucose by using Benedict solution and Fehling solution. During fermentation of liquid glucose by Saccharomyces cerevisiae yeast for 6 days, the changes of physicochemical properties such as pH (5.2 to 3.7), acid content (0.093 % to 0.423 %), glucose content (155 to 63 mg L -1 ) and specific gravity (0.994 to 0.975) during fermentation were determined. After distillation the yield percentage of alcohol in fermented solution is 10 % and the physicochemical properties such as specific gravity, refractive, colour, free acid, free base and alcohol content of the hydrated bioethanol and dehydrated bioethanol were comparatively studied with absolute ethanol. Moreover, the functional groups of bioethanol were analysed by FT IR spectroscopy.