Proximate Analysis and Production of Bio-ethanol from Sweet Potato (<i>Ipomoea batatas</i>) White Cultivars obtained from Samaru Zaria

Abstract

This study entails the production of bioethanol from the peels of sweet potato of white cultivar variety obtained in Zaria, Kaduna State Nigeria. Fresh cultivar with the proximate composition of 72% moisture content, 9.71% ash content, 24.52% crude fiber, 78.74% total carbohydrate and crude protein of 6.42% were hydrolyzed with 3% sulphuric acid solution at 130oC and 60 minutes in an improvised reactor to generate 54.5ml of hydrolyzate after steam pretreatment step. The fermentable reducing sugar of 10.68% was achieved through glucose standardization with UV-spectrophotometer at 540nm wavelength. The fermentation of the hydrolyzate –yeast/media mixture (155ml) at 30^oC for 72hours was achieved by commercial grade saccharomyces cerevisiae to yield 20.5g/54.5ml, which corresponds to 0.8198g/ml specific gravity and 93.6% ethanol concentration. The molecular sieve was eventually adopted in dehydrating the bioethanol to 99.9% (0.8072g/ml) concentration and the final yield of 1.61% per 50g of w. cultivar. FTIR spectrum that declares the ethanolic identity with the stretching vibrations of O-H, C-O and C-H at 3391, 1055 and 2981cm^-1 respectively with the symmetric stretching vibration of the methyl groups at 2930cm^-1.