Bioethanol Production from Godere (Taro Root) (Colocasia Esculenta) and Sweet Potato (Ipomoea Batatas) using Saccharomyces Cerevisiae

This research aims at utilizing taro root and sweet potato for the production of bio-ethanol by using the yeast Saccharomyces cerevisiae. The milled samples of 50gm from each sample were taken then passed through pretreatment, hydrolysis, fermentation and distillation process respectively to produce bio-ethanol. The effects of biomass concentration, acid concentration, temperature and time on distilled and dilute acid hydrolysis were investigated. The milled taro root and s.potato were hydrolysed by distilled water and by dilute sulfuric acid ( 1, 2, 3 and 4) with (6.25, 7.14, 8.33, 10.00, 12.5 and 16.61 % w/v) of biomass concentration at temperature of ( room, 30, 35, 40 and 45°C) for 1, 2, 3, 4 and 5 days. The result showed that the maximum sugar content (83.14 and 86.66 % w/w by phenol-sulfuric acid and Fehling method respectively for taro root, 88.51 and 88.33 % w/w by phenol-sulfuric acid and Fehling method respectively for s.potato,) was obtained from hydrolysis of 10 % biomass concentration containing 2% sulfuric acid at 35 OC for 4 days. The optimized hydrolyzate sample was fermented at optimized pH, 6.00, yeast extract, 4 g/100 mL and at 32.5 OC for 4 days. The maximum 8.075 and 8.77 % w/v for godere and s.potato respectively ethanol content was achieved at 4 days fermentation time. However, as fermentation time increased from 4 days it resulted in decreasing ethanol content.