Bioproduction of Ethanol by Saccharification-Fermentation Process using Sweet Potato (ipomoea batatas) and Irish Potato (solanum tuberosum) as Substrate

Abstract

Ethanol generally are renewable liquids usually produced from sources which can be easily replenished, therefore, the production of ethanol by fermentation using substrate such as carbohydrate crops may provide an economically competitive source of energy by its incorporation into gasoline. Hence, the objective of this paper is the bioproduction of ethanol by saccharification-fermentation process using sweet potato (Ipomoea Batatas) and Irish potato (Solanum Tuberosum) with their peels as substrate with standard techniques for evaluation. The infrared (IR) spectroscopic data of potato extracts revealed that the absorption band of hydroxyl (OH) group of an alcohol ranges from 3747.03 - 3444.40 cm^-1 in all samples analyzed. The ¹H-NMR in CDCl₃ (60 MHz), the proton at δ_H 4.09-4.69 appearing as singlet, integrating for one proton which indicates an hydroxyl group, another proton signal at δ_H 3.46-3.69, appearing as quartet with coupling constant of 7.2 Hz and each integrating for 2 protons, assigned to the methylene group next to the methyl group. The peak observed at δ_H 0.95-1.96 ppm, integrating for three protons with coupling constant of 6.6 Hz, which was assigned to the methyl group on the ethanol structure. The ¹³C-NMR spectrum of all the samples, showed an intense peak at 57.1-57.9 ppm which accounts for methylene peak on ethanol and an upfield carbon signal at 17.4-18.0, which was assigned to the methyl carbon in ethanol structure. The Nuclear Magnetic Resonance (NMR) results showed the presence of ethanol in the samples analyzed. Consequently, the refractive index result showed that all the extracts have a significant level of alcohol content.