Feasibility Studies on the Preparation of Bioethanol from Taro Roots

In this research, taro roots were used as a source for preparation of bioethanol by enzymatic hydrolysis followed by fermentation. In enzymatic hydrolysis, termamyl (α-amylase) was used for liquefaction and saczyme (glucoamylase) for saccharification. The substrate concentration, enzyme volume used and liquefaction time were investigated for maximum yield of fermentable sugar in liquefaction step. The maximum fermentable sugars of 185 mg/g have obtained by liquefaction using 250 mg/L substrate concentration, 4 mL of termamyl and 3 h of liquefaction time. In saccharification step, effects of enzyme and saccharification time on the yield of fermentable sugar were also studied. The fermentable sugar obtained in enzymatic hydrolysis was determined by Lane and Eynon method. The maximum fermentable sugar of 722 mg/g was obtained when saccharification was carried out with 9 mL of saczyme for saccharification time of 10 h at 60 °C and pH 4.3. The fermentable sugar from enzymatic hydrolysis was fermented by using Saccharomyces cerevissae. In the fermentation process, concentration of fermentable sugar, fermentation time, fermentation temperature and yeast (Saccharomyces cerevissae) content were studied for the maximum strength of bioethanol. After fermentation, the ethanol content in broth was determined by alcohol meter and the maximum strength, 10 % (v/v) was obtained under the conditions of 2.4 % (w/w) yeast content, 200 g/L of substrate concentration (sugar), 35°C of fermentation temperature and 4 day-course of fermentation time. After fractional distillation, the ethanol strength was determined by gas chromatography (GC). In addition, total acidity, pH, refractive index and chloride content and specific gravity of bioethanol were determined