Bio-Ethanol Production from Cocoyam Peels using Enzymatic Hydrolysis

Abstract

This study investigated the great potential of cocoyam peels (non-edible waste material) as suitable substrate for bio-ethanol production using enzymatic hydrolysis process. The raw material was subjected to pretreatment prior to the hydrolysis and fermentation processes. Several experimental analyses to determine the suitability of this food waste as bioethanol feedstock -the proximate analyses, enzymatic hydrolysis, analysis of simple sugars, fermentation experiments, kinetics and optimization of the enzymatic hydrolysis and fermentation were done. Cellulase secreted from Aspergillus niger was used for the hydrolysis of the peels in a separate hydrolysis. Similarly, commercial saccharomyces cerevisiae was also used for the fermentation of the hydrolyzate. The kinetic studies revealed that Michaelis Menten model was suitable for the enzymatic hydrolysis and fermentation processes. The Seaman kinetic equation for the enzymatic hydrolysis was solved using Microsoft Excel Solver. The Box-Behnken of Response Surface Method (RSM) was employed to optimize the hydrolysis yield. From the numerical optimization solution, simple sugar yield from enzymatic hydrolysis was 57.5%. The result also showed that the highest ethanol yield of 7.15%v/v for 4 days with pH value of 7.3 was obtained.