Production of Bioethanol from Agro-food Waste (Potato Peel) with the Aid of NPK Fertilizer and Moringa Leaf as Activators

Ukpaka C. P; Ikenyiri P N

Abstract

In this work, the production of ethanol with the aid of activators was investigated. Two-step hydrolysis of sweet potato peel was studied. Acid hydrolysis was carried out using dilute sulphuric acid, while enzyme hydrolysis was studied using Aspergillus niger inoculum. The effect of activators on ethanol yield was also investigated. Saccharification was studied using aspergillus niger which is a starch degrading organism to generate convertible sugar. Fermentation was carried out by saccharomyces cerevisiae which is an ethanol producing microorganism. The values of optimum time, pH, temperature and other operating conditions differ with the various steps. Ethanol production from potato peel waste was carried out under anaerobic conditions using saccharomyces cerevisiae yeast at 32oC. Different sources of nitrogen NPK fertilizer and moringa leave with mass of 2g to 10g were added to promote the ethanol yields and prevent by-products formation. With the control medium, the ethanol produced was 19.62% with fermentation time of 72 hours. With the addition of moringa as a supplementary nitrogen source, the yield of ethanol increased to 31% as the quantity of moringa increased from 2g10g of fermentation time 72 hours. Similarly using NPK fertilizer as a supplementary nitrogen source gave an ethanol yield of 27.8% with a fermentation time of 72 hours. The addition of NPK fertilizer and moringa significantly increased glucose utilization, ethanol production when compared with control media. There was significant difference in ethanol yield when the supplementary nitrogen sources (NPK fertilizer and moringa leave) were added compared with the control media. The higher values of ethanol yield obtained when supplementary nitrogen sources were added indicate that both activators succeed in efficiently reducing the formation of by- products during anaerobic fermentation compared with that of the control media where the saccharomyces cerevisae is the only available nitrogen source. It was observed that as the mass of NPK fertilizer and moringa were increased from 2g-10g, the yield of ethanol also increases.