Hydrolysis and Analysis of Agricultural Wastes Using Mineral Acids for Possible Glucose Synthesis

Abstract

This work focuses on conversion of agricultural wastes into fermentable sugar via acid hydrolysis. Proximate and ultimate analysis was carried out to ascertain the physiochemical properties of the biomass feedstock and fermentable sugar. Mineral acid such as hydrochloric acid (HCl) and sulfuric acid (H2SO4) was used as the media for the conversion of plantain peels and water yam peels into fermentable sugar. Concentration of glucose was analyzed using DNS techniques. Modelling of the process was done using three established kinetic models to determine the rate determining step. Results showed that untreated plantain peels and water yam peels contained 30.1% and 6.4% cellulose but increased significantly to 55.1% and 10.03% after hydrolysis indicating increase in fermentable sugar. In comparing the same conditions of plantain-HCl, plantain-HS, water yam-HCl and water yam-HS at 80°C with acid concentration/sample ratio of 0.5:2 at time 90 mins, plantain peels with HCl yield highest concentration of 4.09mg/l fermentable sugar while at the same condition water yam produced 2.031mg/l. Second order kinetic model appears to be the best fit for the process with better correlation coefficient R2 >99% with HCl and plantain peels at a reaction temperature of 60oC conforming to the rate determining step. The model demonstrated an increasing rate constant with increase in temperature which agrees with the magnitude of the hydrolysis process. This work will help in solving the energy need of our society if commercialized. Also, it can serve as a viable alternative to environmental cleanliness because wastes will become raw materials. Plantain peels and water yam peels demonstrated good potential as a source of fermentable sugar but plantain peels performed better.