Study of the effect of process parameters on the yield of fermentable sugar from red cocoyam (Xanthosoma sagittifolium) peels via acid and enzyme hydrolysis

Abstract

The aim of this work is to study the acid and enzymatic hydrolysis of cocoyam peels using HCl, H2S04 acids and cellulase enzyme. The cellulase was secreted from Aspergillus Niger (A. niger) fungi. The proximate analysis of the substrate showed that cocoyam peel is a lignocellulosic biomass with a cellulose composition of 48%. The effect of the process parameters (time, temperature, acid concentration and pH) on the yield of glucose in acid and enzymatic hydrolysis of the cocoyam peel was respectively investigated. Maximum glucose yield of 44.5% was obtained after 3 days of enzymatic hydrolysis at 30°C and pH 5. The HCl acid hydrolysis showed a maximum glucose yield of 27.3% at 70°C, 5% HCl after 180 minutes. The glucose yield in H2S04 hydrolysis was relatively lower than that of the HCl with a maximum yield of 26.5% at 70°C, 5% H2SO4 after 180 minutes. In addition to, the functional groups present in the glucose synthesized from cocoyam ground peels and the standard glucose were evaluated using Fourier Transformed Infrared (FTIR). The FTIR results showed similarities in the functional groups present in both sugars. Cocoyam peel can be used for the production of glucose and further fermentative process to produce ethanol.